,,pleasures ,,of ,,the ,,telescope ,,an ,,illustrated ,,guide ,,for ,,amateur ,,astronomers ,,and ,a ,,popular ,,description ,,of ,,the ,,chief ,,wonders ,,of ,,the ,,heavens ,,for ,,general ,,readers ,,by ,,garrett ,p4 ,,serviss ,,author ,,of ,,astronomy ,,with ,,an ,,opera-,,glass ,this being made1 ,he yearned for worlds to make ,from other chaos out beyond our night-- ,for to create is still ,god's prime delight4 ,the large moon1 all alone1 sailed her dark lake1 ,and the first tides were moving to her might2 ,then ,darkness trembled1 and began to quake ,big with the birth of stars1 and when ,he spake ,a million worlds leapt into radiant light4 ,,lloyd ,,mifflin4 ,,with ,,many ,,illustrations ,,new ,,york ,d4 ,,appleton ,,and ,,company #aija ,,copyright1 #aija1 ,,by ,d4 ,,appleton ,,and ,,company4 ,,preface ,by the introduction of a complete series of star maps1 drawn specially for the use of the amateur and distributed through the body of the work1 thus facilitating consultation1 it is believed that this book makes a step in advance of its predecessors4 ,the maps show all of the stars visible to the naked eye in the regions of sky represented1 and1 in addition1 some stars that can only be seen with optical aid4 ,the latter have been placed in the maps as guide posts in the telescopic field to assist those who are searching for faint and inconspicuous objects referred to in the text4 ,as the book was not written for those who possess the equipment of an observatory1 with telescopes driven by clockwork and provided with graduated circles1 right ascensions and declinations are not given4 ,all of the telescopic phenomena described are1 however1 represented in the maps4 ,star clusters are indicated by a conventional symbol1 and nebul by a little white circle2 while a small cross serves to mark the places where notable new stars have appeared4 ,the relative magnitudes of the stars are approximately shown by the dimensions of their symbols in the maps1 the smaller stars being represented by white dots and the larger by star-shaped figures4 ,in regard to binary stars1 it should be remembered that1 in many cases1 their distances and angles of position change so rapidly that any statement concerning them remains valid only for a few years at the most4 ,there is also much confusion among the measurements announced by different authorities4 ,in general1 the most recent measurements obtainable in #aijj are given in the text1 but the observer who wishes to study close and rapid binaries will do well to revise his information about them as frequently as possible4 ,an excellent list of double stars kept up to date1 will be found in the annual ,companion to the ,observatory1 published in ,london4 ,in the lunar charts the plan of inserting the names of the principal formations has been preferred to that usually followed1 of indicating them only by numbers1 accompanied by a key list4 ,even in the most detailed charts of the moon only a part of what is visible with telescopes can be shown1 and the representation1 at best1 must be merely approximate4 ,it is simply a question of what to include and what to omit2 and in the present case the probable needs of the amateur observer have governed the selection--readiness and convenience of reference being the chief aim4 ,it should1 perhaps1 be said here that the various chapters composing this book--like those of ,astronomy with an ,opera-glass--were1 in their original form1 with the single exception of ,chapter ,,ix1 published in ,appletons' ,popular ,science ,monthly4 ,the author1 it is needless to say1 was much gratified by the expressed wish of many readers that these scattered papers should be revised and collected in a more permanent form4 ,as bearing upon the general subject of the book1 a chapter has been added1 at the end1 treating on the question of the existence of planets among the stars4 ,this also first appeared in the periodical above mentioned4 ,in conclusion1 the author wishes for his readers as great a pleasure in the use of the telescope as he himself has enjoyed4 ,g4 ,p4 ,s4 ,,borough ,,of ,,brooklyn1 ,,new ,,york1 ,january1 #aija4 ,,contents ,,chapter ,i ,,page ,,the ,,selection ,,and ,,testing ,,of ,a ,,glass #a ,how to get a good telescope--,difference between reflectors and refractors--,how a telescope is made achromatic--,the way to test a telescope on stars4 ,,chapter ,,ii ,,in ,,the ,,starry ,,heavens #ai ,orion and its wonders1 ,lepus1 ,canis ,major1 ,argo1 ,monoceros1 ,canis ,minor1 and the ,head of ,hydra4 ,,chapter ,,iii ,,from ,,gemini ,,to ,,leo ,,and ,,round ,,about #ch ,the zodiacal constellations ,gemini1 ,cancer1 and ,leo1 and their neighbors ,auriga1 the ,lynx1 ,hydra1 ,sextans1 and ,coma ,berenices4 ,,chapter ,,iv ,,virgo ,,and ,,her ,,neighbors #eg ,crater and ,corvus1 ,hydra1 ,virgo1 the ,field of the ,nebul1 ,libra1 ,botes1 and the great ,arcturus1 ,canes ,venatici1 and ,corona ,borealis4 ,,chapter ,v ,,in ,,summer ,,star-,,lands #ge ,scorpio and its red-green gem1 ,ophiuchus1 ,sagittarius1 ,scutum ,sobieskii1 ,capricornus1 ,serpens1 ,hercules1 ,draco1 ,aquila1 and ,delphinus4 ,,chapter ,,vi ,,from ,,lyra ,,to ,,eridanus #ig ,lyra and its brilliant ,vega1 ,cygnus1 ,vulpecula1 ,aquarius1 ,equuleus1 ,pegasus1 ,cetus1 and ,eridanus4 ,,chapter ,,vii ,,pisces1 ,,aries1 ,,taurus1 ,,and ,,the ,,northern ,,mars #aag ,the first double star ever discovered1 the ,pleiades and their photographic wonders1 the ,royal ,family of the ,sky1 ,andromeda1 ,cassiopeia1 ,perseus and ,cepheus1 ,ursa ,major1 ,camelopardalus1 ,ursa ,minor1 and the ,pole ,star4 ,,chapter ,,viii ,,scenes ,,on ,,the ,,planets #aci ,jupiter1 its belts and its moons--,saturn1 the ringed planet--,saturn's moons and ,roche's limit--,mars and its white polar caps and so-called seas and continents--,venus and her atmosphere--,the peculiar rotations of ,venus and ,mercury4 ,,chapter ,,ix ,,the ,,mountains ,,and ,,plains ,,of ,,the ,,moon ,,and ,,the ,,spectacles ,,of ,,the ,,sun #aef ,peculiarities of the lunar landscapes--,the so-called seas1 the craters1 the ring mountains1 the inclosed plains1 the mountain ranges1 ,tycho's mysterious streaks1 and other lunar features described--,how to view the sun and its spots4 ,,chapter ,x ,,are ,,there ,,planets ,,among ,,the ,,stars8 #ahc ,significance of ,dr4 ,see's observations--,why our telescopes do not show planets circling around distant suns--,reasons for thinking that such planets may exist--,the bearing of stellar evolution on the question4 ,,pleasures ,,of ,,the ,,telescope ,,chapter ,i ,,the ,,selection ,,and ,,testing ,,of ,a ,,glass ,o telescope1 instrument of much knowledge1 more precious than any scepter6 ,is not he who holds thee in his hand made king and lord of the works of ,god8--,,john ,,kepler4 ,if the pure and elevated pleasure to be derived from the possession and use of a good telescope of three1 four1 five1 or six inches aperture were generally known1 ,i am certain that no instrument of science would be more commonly found in the homes of intelligent people4 ,the writer1 when a boy1 discovered unexpected powers in a pocket telescope not more than fourteen inches long when extended1 and magnifying ten or twelve times4 ,it became his dream1 which was afterward realized1 to possess a more powerful telescope1 a real astronomical glass1 with which he could see the beauties of the double stars1 the craters of the moon1 the spots on the sun1 the belts and satellites of ,jupiter1 the rings of ,saturn1 the extraordinary shapes of the nebul1 the crowds of stars in the ,milky ,way1 and the great stellar clusters4 ,and now he would do what he can to persuade others1 who perhaps are not aware how near at hand it lies1 to look for themselves into the wonder-world of the astronomers4 ,there is only one way in which you can be sure of getting a good telescope4 ,first1 decide how large a glass you are to have1 then go to a maker of established reputation1 fix upon the price you are willing to pay--remembering that good work is never cheap--and finally see that the instrument furnished to you answers the proper tests for a telescope of its size4 ,there are telescopes and telescopes4 ,occasionally a rare combination of perfect homogeneity in the material1 complete harmony between the two kinds of glass of which the objective is composed1 and lens surfaces whose curves are absolutely right1 produces a telescope whose owner would part with his last dollar sooner than with it4 ,such treasures of the lens-maker's art can not1 perhaps1 be commanded at will1 yet1 they are turned out with increasing frequency1 and the best artists are generally able1 at all times1 to approximate so closely to perfection that any shortcoming may be disregarded4 ,in what is said above ,i refer1 of course1 to the refracting telescope1 which is the form of instrument that ,i should recommend to all amateurs in preference to the reflector4 ,but1 before proceeding further1 it may be well to recall briefly the principal points of difference between these two kinds of telescopes4 ,the purpose of a telescope of either description is1 first1 to form an image of the object looked at by concentrating at a focus the rays of light proceeding from that object4 ,the refractor achieves this by means of a carefully shaped lens1 called the object glass1 or objective4 ,the reflector1 on the other hand1 forms the image at the focus of a concave mirror4 ,illustration3 ,,image ,,at ,,the ,,focus ,,of ,a ,,lens4 ,a very pretty little experiment1 which illustrates these two methods of forming an optical image1 and1 by way of corollary1 exemplifies the essential difference between refracting and reflecting telescopes1 may be performed by any one who possesses a reading glass and a magnifying hand mirror4 ,in a room that is not too brightly illuminated pin a sheet of white paper on the wall opposite to a window that1 by preference1 should face the north1 or away from the position of the sun4 ,taking first the reading glass1 hold it between the window and the wall parallel to the sheet of paper1 and a foot or more distant from the latter4 ,by moving it to and fro a little you will be able to find a distance1 corresponding to the focal length of the lens1 at which a picture of the window is formed on the paper4 ,this picture1 or image1 will be upside down1 because the rays of light cross at the focus4 ,by moving the glass a little closer to the wall you will cause the picture of the window to become indistinct1 while a beautiful image of the houses1 trees1 or other objects of the outdoor world beyond1 will be formed upon the paper4 ,we thus learn that the distance of the image from the lens varies with the distance of the object whose image is formed4 ,in precisely a similar manner an image is formed at the focus of the object glass of a refracting telescope4 ,illustration3 ,,image ,,at ,,the ,,focus ,,of ,a ,,concave ,,mirror4 ,take next your magnifying or concave mirror1 and detaching the sheet of paper from the wall1 hold it nearly in front of the mirror between the latter and the window4 ,when you have adjusted the distance to the focal length of the mirror1 you will see an image of the window projected upon the paper1 and by varying the distance1 as before1 you will be able to produce1 at will1 pictures of nearer or more remote objects4 ,it is in this way that images are formed at the focus of the mirror of a reflecting telescope4 ,now1 you will have observed that the chief apparent difference between these two methods of forming an image of distant objects is that in the first case the rays of light1 passing through the transparent lens1 are brought to a focus on the side opposite to that where the real object is1 while in the second case the rays1 being reflected from the brilliant surface of the opaque mirror1 come to a focus on the same side as that on which the object itself is4 ,from this follows the most striking difference in the method of using refracting and reflecting telescopes4 ,in the refractor the observer looks toward the object2 in the reflector he looks away from it4 ,sir ,william ,herschel made his great discoveries with his back to the sky4 ,he used reflecting telescopes4 ,this principle1 again1 can be readily illustrated by means of our simple experiment with a reading glass and a magnifying mirror4 ,hold the reading glass between the eye and a distant object with one hand1 and with the other hand place a smaller lens such as a pocket magnifier1 near the eye1 and in line with the reading glass4 ,move the two carefully until they are at a distance apart equal to the sum of the focal lengths of the lenses1 and you will see a magnified image of the distant object4 ,in other words1 you have constructed a simple refracting telescope4 ,then take the magnifying mirror1 and1 turning your back to the object to be looked at1 use the small lens as before--that is to say1 hold it between your eye and the mirror1 so that its distance from the latter is equal to the sum of the focal lengths of the mirror and the lens1 and you will see again a magnified image of the distant object4 ,this time it is a reflecting telescope that you hold in your hands4 ,the magnification of the image reminds us of the second purpose which is subserved by a telescope4 ,a telescope1 whether refracting or reflecting1 consists of two essential parts1 the first being a lens1 or a mirror1 to form an image1 and the second a microscope1 called an eyepiece1 to magnify the image4 ,the same eyepieces will serve for either the reflector or the refractor4 ,but in order that the magnification may be effective1 and serve to reveal what could not be seen without it1 the image itself must be as nearly perfect as possible2 this requires that every ray of light that forms the image shall be brought to a point in the image precisely corresponding to that from which it emanates in the real object4 ,in reflectors this is effected by giving a parabolic form to the concave surface of the mirror4 ,in refractors there is a twofold difficulty to be overcome4 ,in the first place1 a lens with spherical surfaces does not bend all the rays that pass through it to a focus at precisely the same distance4 ,the rays that pass near the outer edge of the lens have a shorter focus than that of the rays which pass near the center of the lens2 this is called spherical aberration4 ,a similar phenomenon occurs with a concave mirror whose surface is spherical4 ,in that case1 as we have seen1 the difficulty is overcome by giving the mirror a parabolic instead of a spherical form4 ,in an analogous way the spherical aberration of a lens can be corrected by altering its curves1 but the second difficulty that arises with a lens is not so easily disposed of3 this is what is called chromatic aberration4 ,it is due to the fact that the rays belonging to different parts of the spectrum have different degrees of refrangibility1 or1 in other words1 that they come to a focus at different distances from the lens2 and this is independent of the form of the lens4 ,the blue rays come to a focus first1 then the yellow1 and finally the red4 ,it results from this scattering of the spectral rays along the axis of the lens that there is no single and exact focus where all meet1 and that the image of a star1 for instance1 formed by an ordinary lens1 even if the spherical aberration has been corrected1 appears blurred and discolored4 ,there is no such difficulty with a mirror1 because there is in that case no refraction of the light1 and consequently no splitting up of the elements of the spectrum4 ,in order to get around the obstacle formed by chromatic aberration it is necessary to make the object glass of a refractor consist of two lenses1 each composed of a different kind of glass4 ,one of the most interesting facts in the history of the telescope is that ,sir ,isaac ,newton could see no hope that chromatic aberration would be overcome1 and accordingly turned his attention to the improvement of the reflecting telescope and devised a form of that instrument which still goes under his name4 ,and even after ,chester ,more ,hall in #agbi1 and ,john ,dollond in #ageg1 had shown that chromatic aberration could be nearly eliminated by the combination of a flint-glass lens with one of crown glass1 ,william ,herschel1 who began his observations in #aggd1 devoted his skill entirely to the making of reflectors1 seeing no prospect of much advance in the power of refractors4 ,a refracting telescope which has been freed from the effects of chromatic aberration is called achromatic4 ,the principle upon which its construction depends is that by combining lenses of different dispersive power the separation of the spectral colors in the image can be corrected while the convergence of the rays of light toward a focus is not destroyed4 ,flint glass effects a greater dispersion than crown glass nearly in the ratio of three to two4 ,the chromatic combination consists of a convex lens of crown backed by a concave1 or plano-concave1 lens of flint4 ,when these two lenses are made of focal lengths which are directly proportional to their dispersions1 they give a practically colorless image at their common focus4 ,the skill of the telescope-maker and the excellence of his work depend upon the selection of the glasses to be combined and his manipulation of the curves of the lenses4 ,illustration3 ,,achromatic ,,object ,,glass4 a1 crown glass2 b1 flint glass4 ,now1 the reader may ask1 ,since reflectors require no correction for color dispersion1 while that correction is only approximately effected by the combination of two kinds of lenses and two kinds of glass in a refractor1 why is not the reflector preferable to the refractor8 ,the answer is1 that the refractor gives more light and better definition4 ,it is superior in the first respect because a lens transmits more light than a mirror reflects4 ,professor ,young has remarked that about eighty-two per cent of the light reaches the eye in a good refractor1 while in a ,newtonian reflector1 in average condition1 the percentage seldom exceeds fifty per cent1 and more frequently is lower than higher4 ,the superiority of the refractor in regard to definition arises from the fact that any distortion at the surface of a mirror affects the direction of a ray of light three times as much as the same distortion would do at the surface of a lens4 ,and this applies equally both to permanent errors of curvature and to temporary distortions produced by strains and by inequality of temperature4 ,the perfect achromatism of a reflector is1 of course1 a great advantage1 but the chromatic aberration of refractors is now so well corrected that their inferiority in that respect may be disregarded4 ,it must be admitted that reflectors are cheaper and easier to make1 but1 on the other hand1 they require more care1 and their mirrors frequently need resilvering1 while an object glass with reasonable care never gets seriously out of order1 and will last for many a lifetime4 ,enough has now1 perhaps1 been said about the respective properties of object glasses and mirrors1 but a word should be added concerning eyepieces4 ,without a good eyepiece the best telescope will not perform well4 ,the simplest of all eyepieces is a single double-convex lens4 ,with such a lens the magnifying power of the telescope is measured by the ratio of the focal length of the objective to that of the eye lens4 ,suppose the first is sixty inches and the latter half an inch2 then the magnifying power will be a hundred and twenty diameters--i4 e41 the disk of a planet1 for instance1 will be enlarged a hundred and twenty times along each diameter1 and its area will be enlarged the square of a hundred and twenty1 or fourteen thousand four hundred times4 ,but in reckoning magnifying power1 diameter1 not area1 is always considered4 ,for practical use an eyepiece composed of an ordinary single lens is seldom advantageous1 because good definition can only be obtained in the center of the field4 ,lenses made according to special formul1 however1 and called solid eyepieces1 give excellent results1 and for high powers are often to be preferred to any other4 ,the eyepieces usually furnished with telescopes are1 in their essential principles1 compound microscopes1 and they are of two descriptions1 positive and negative4 ,the former generally goes under the name of its inventor1 ,ramsden1 and the latter is named after great ,dutch astronomer1 ,huygens4 ,the ,huygens eyepiece consists of two plano-convex lenses whose focal lengths are in the ratio of three to one4 ,the smaller lens is placed next to the eye4 ,both lenses have their convex surfaces toward the object glass1 and their distance apart is equal to half the sum of their focal lengths4 ,in this kind of eyepiece the image is formed between the two lenses1 and if the work is properly done such an eyepiece is achromatic4 ,it is therefore generally preferred for mere seeing purposes4 ,in the ,ramsden eyepiece two plano-convex lenses are also used1 but they are of equal focal length1 are placed at a distance apart equal to two thirds of the focal length of either1 and have their convex sides facing one another4 ,with such an eyepiece the image viewed is beyond the farther or field lens instead of between the two lenses1 and as this fact renders it easier to adjust wires or lines for measuring purposes in the focus of the eyepiece1 the ,ramsden construction is used when a micrometer is to be employed4 ,in order to ascertain the magnifying power which an eyepiece gives when applied to a telescope it is necessary to know the equivalent1 or combined1 focal length of the two lenses4 ,two simple rules1 easily remembered1 supply the means of ascertaining this4 ,the equivalent focal length of a negative or ,huygens eyepiece is equal to half the focal length of the larger or field lens4 ,the equivalent focal length of a positive or ,ramsden eyepiece is equal to three fourths of the focal length of either of the lenses4 ,having ascertained the equivalent focal length of the eyepiece1 it is only necessary to divide it into the focal length of the object glass 7or mirror7 in order to know the magnifying power of your telescope when that particular eyepiece is in use4 ,illustration3 ,,negative ,,eyepiece4 ,illustration3 ,,positive ,,eyepiece4 ,a first-class object glass 7or mirror7 will bear a magnifying power of one hundred to the inch of aperture when the air is in good condition--that is1 if you are looking at stars4 ,if you are viewing the moon1 or a planet1 better results will always be obtained with lower powers--say fifty to the inch at the most4 ,and under ordinary atmospheric conditions a power of from fifty to seventy-five to the inch is far better for stars than a higher power4 ,with a five-inch telescope that would mean from two hundred and fifty to three hundred and seventy-five diameters1 and such powers should only be applied for the sake of separating very close double stars4 ,as a general rule1 the lowest power that will distinctly show what you desire to see gives the best results4 ,the experienced observer never uses as high powers as the beginner does4 ,the number of eyepieces purchased with a telescope should never be less than three--a very low power--say ten to the inch2 a very high power1 seventy-five or one hundred to the inch1 for occasional use2 and a medium power--say forty to the inch--for general use4 ,if you can afford it1 get a full battery of eyepieces--six or eight1 or a dozen--for experience shows that different objects require different powers in order to be best seen1 and1 moreover1 a slight change of power is frequently a great relief to the eye4 ,there is one other thing of great importance to be considered in purchasing a telescope--the mounting4 ,if your glass is not well mounted on a steady and easily managed stand1 you might better have spent your money for something more useful4 ,i have endured hours of torment while trying to see stars through a telescope that was shivering in the wind and dancing to every motion of the bystanders1 to say nothing of the wriggling contortions caused by the application of my own fingers to the focusing screw4 ,the best of all stands is a solid iron pillar firmly fastened into a brick or stone pier1 sunk at least four feet in the ground1 and surmounted by a well-made equatorial bearing whose polar axis has been carefully placed in the meridian4 ,it can be readily protected from the weather by means of a wooden hood or a rubber sheet1 while the tube of the telescope may be kept indoors1 being carried out and placed on its bearing only when observations are to be made4 ,with such a mounting you can laugh at the observatories with their cumbersome domes1 for the best of all observatories is the open air4 ,but if you dislike the labor of carrying and adjusting the tube every time it is used1 and are both fond of and able to procure luxuries1 then1 after all1 perhaps1 you had better have the observatory1 dome1 draughts and all4 ,the next best thing in the way of a mounting is a portable tripod stand4 ,this may be furnished either with an equatorial bearing for the telescope1 or an altazimuth arrangement which permits both up-and-down and horizontal motions4 ,the latter is cheaper than the equatorial and proportionately inferior in usefulness and convenience4 ,the essential principle of the equatorial bearing is motion about two axes placed at right angles to one another4 ,when the polar axis is in the meridian1 and inclined at an angle equal to the latitude of the place1 the telescope can be moved about the two axes in such a way as to point to any quarter of the sky1 and the motion of a star1 arising from the earthy rotation1 can be followed hour after hour without disturbing the instrument4 ,when thus mounted1 the telescope may be driven by clockwork1 or by hand with the aid of a screw geared to a handle carrying a universal joint4 ,and now for testing the telescope4 ,it has already been remarked that the excellence of a telescope depends upon the perfection of the image formed at the focus of the objective4 ,in what follows ,i have only a refractor in mind1 although the same principles would apply to a reflector4 ,with a little practice anybody who has a correct eye can form a fair judgment of the excellence of a telescopic image4 ,suppose we have our telescope steadily mounted out of doors 7if you value your peace of mind you will not try to use a telescope pointed out of a window1 especially in winter71 and suppose we begin our observations with the pole star1 employing a magnifying power of sixty or seventy to the inch4 ,our first object is to see if the optician has given us a good glass4 ,if the air is not reasonably steady we had better postpone our experiment to another night1 because we shall find that the star as seen in the telescope flickers and boils1 and behaves in so extraordinary a fashion that there is no more definition in the image than there is steadiness in a bluebottle buzzing on a window pane4 ,but if the night is a fine one the star image will be quiescent1 and then we may note the following particulars3 ,the real image is a minute bright disk1 about one second of arc in diameter if we are using a four-and-a-half or five-inch telescope1 and surrounded by one very thin ring of light1 and the fragments1 so to speak1 of one or possibly two similar rings a little farther from the disk1 and visible1 perhaps1 only by glimpses4 ,these diffraction rings arise from the undulatory nature of light1 and their distance apart as well as the diameter of the central disk depend upon the length of the waves of light4 ,if the telescope is a really good one1 and both object glass and eyepiece are properly adjusted1 the disk will be perfectly round1 slightly softer at the edge1 but otherwise equally bright throughout2 and the ring or rings surrounding it will be exactly concentric1 and not brighter on one side than on another4 ,even if our telescope were only two inches or two inches and a half in aperture we should at once notice a little bluish star1 the mere ghost of a star in a small telescope1 hovering near the polar star4 ,it is the celebrated companion1 but we shall see it again when we have more time to study it4 ,now let us put the star out of focus by turning the focusing screw4 ,suppose we turn it in such a way that the eyepiece moves slightly outside the focus1 or away from the object glass4 ,very beautiful phenomena immediately begin to make their appearance4 ,a slight motion outward causes the little disk to expand perceptibly1 and just as this expansion commences1 a bright-red point appears at the precise center of the disk4 ,but1 the outward motion continuing1 this red center disappears1 and is replaced by a blue center1 which gradually expands into a sort of flare over the middle of the disk4 ,the disk itself has in the mean time enlarged into a series of concentric bright rings1 graduated in luminosity with beautiful precision from center toward circumference4 ,the outermost ring is considerably brighter1 however1 than it would be if the same gradation applied to it as applies to the inner rings1 and it is surrounded1 moreover1 on its outer edge by a slight flare which tends to increase its apparent width4 ,next let us return to the focus and then move the eyepiece gradually inside the focal point or plane4 ,once more the star disk expands into a series of circles1 and1 if we except the color phenomena noticed outside the focus1 these circles are precisely like those seen before in arrangement1 in size1 and in brightness4 ,if they were not the same1 we should pronounce the telescope to be imperfect4 ,there is one other difference1 however1 besides the absence of the blue central flare1 and that is a faint reddish edging around the outer ring when the expansion inside the focus is not carried very far4 ,upon continuing to move the eyepiece inside or outside the focus we observe that the system of rings becomes larger1 while the rings themselves rapidly increase in number1 becoming at the same time individually thinner and fainter4 ,illustration3 ,,the ,,star ,,image4 ,by studying the appearance of the star disk when in focus and of the rings when out of focus on either side1 an experienced eye can readily detect any fault that a telescope may have4 ,the amateur1 of course1 can only learn to do this by considerable practice4 ,any glaring and serious fault1 however1 will easily make itself manifest4 ,suppose1 for example1 we observe that the image of a star instead of being perfectly round is oblong1 and that a similar defect appears in the form of the rings when the eyepiece is put out of focus4 ,we know at once that something is wrong2 but the trouble may lie either in the object glass1 in the eyepiece1 in the eye of the observer himself1 or in the adjustment of the lenses in the tube4 ,a careful examination of the image and the out-of-focus circles will enable us to determine with which of these sources of error we have to deal4 ,if the star image when in focus has a sort of wing on one side1 and if the rings out of focus expand eccentrically1 appearing wider and larger on one side than on the other1 being at the same time brightest on the least expanded side1 then the object glass is probably not at right angles to the axis of the tube and requires readjustment4 ,that part of the object glass on the side where the rings appear most expanded and faintest needs to be pushed slightly inward4 ,this can be effected by means of counterscrews placed for that purpose in or around the cell4 ,but it1 after we have got the object glass properly squared to the axis of the tube or the line of sight1 the image and the ring system in and out of focus still appear oblong1 the fault of astigmatism must exist either in the objective1 the eyepiece1 or the eye4 ,the chances are very great that it is the eye itself that is at fault4 ,we may be certain of this if we find1 on turning the head so as to look into the telescope with the eye in different positions1 that the oblong image turns with the head of the observer1 keeping its major axis continually in the same relative position with respect to the eye4 ,the remedy then is to consult an oculist and get a pair of cylindrical eyeglasses4 ,if the oblong image does not turn round with the eye1 but does turn when the eyepiece is twisted round1 then the astigmatism is in the latter4 ,if1 finally1 it does not follow either the eye or the eyepiece1 it is the objective that is at fault4 ,but instead of being oblong1 the image and the rings may be misshapen in some other way4 ,if they are three-cornered1 it is probable that the object glass is subjected to undue pressure in its cell4 ,this1 if the telescope has been brought out on a cool night from a warm room1 may arise from the unequal contraction of the metal work and the glass as they cool off4 ,in fact1 no good star image can be got while a telescope is assuming the temperature of the surrounding atmosphere4 ,even the air inclosed in the tube is capable of making much trouble until its temperature has sunk to the level of that outside4 ,half an hour at least is required for a telescope to adjust itself to out-of-door temperature1 except in the summer time1 and it is better to allow an hour or two for such adjustment in cold weather4 ,any irregularity in the shape of the rings which persists after the lenses have been accurately adjusted and the telescope has properly cooled may be ascribed to imperfections1 such as veins or spots of unequal density in the glass forming the objective4 ,illustration3 ,,the ,,out-,,of-,,focus ,,rings4 #a1 ,correct figure2 #b and #c1 spherical aberration4 ,the spherical aberration of an object glass may be undercorrected or overcorrected4 ,in the former case the central rings inside the focus will appear faint and the outer ones unduly strong1 while outside the focus the central rings will be too bright and the outer ones too feeble4 ,but if the aberration is overcorrected the central rings will be overbright inside the focus and abnormally faint outside the focus4 ,illustration3 ,,two ,,views ,,of ,,mars ,,in #ahib4 ,the smaller with a three-and-three-eighths-inch telescope2 the larger with a nine-inch4 ,assuming that we have a telescope in which no obvious fault is discernible1 the next thing is to test its powers in actual work4 ,in what is to follow ,i shall endeavor to describe some of the principal objects in the heavens from which the amateur observer may expect to derive pleasure and instruction1 and which may at the same time serve as tests of the excellence of his telescope4 ,no one should be deterred or discouraged in the study of celestial objects by the apparent insignificance of his means of observation4 ,the accompanying pictures of the planet ,mars may serve as an indication of the fact that a small telescope is frequently capable of doing work that appears by no means contemptible when placed side by side with that of the greater instruments of the observatories4 ,,chapter ,,ii ,,in ,,the ,,starry ,,heavens ,now constellations1 ,muse1 and signs rehearse2 ,in order let them sparkle in thy verse4--,,manilius4 ,let us imagine ourselves the happy possessors of three properly mounted telescopes of five1 four1 and three inches aperture1 respectively4 ,a fine midwinter evening has come along1 the air is clear1 cool1 and steady1 and the heavens1 of that almost invisible violet which is reserved for the lovers of celestial scenery1 are spangled with stars that hardly twinkle4 ,we need not disturb our minds about a few thin clouds here and there floating lazily in the high air2 they announce a change of weather1 but they will not trouble us to-night4 ,which way shall we look8 ,our eyes will answer the question for us4 ,however we may direct them1 they instinctively return to the south1 and are lifted to behold ,orion in his glory1 now near the meridian and midway to the zenith1 with ,taurus shaking the glittering ,pleiades before him1 and ,canis ,major with the flaming ,dog ,star following at his heels4 ,not only is ,orion the most brilliant of all constellations to the casual star-gazer1 but it contains the richest mines that the delver for telescopic treasures can anywhere discover4 ,we could not have made a better beginning1 for here within a space of a few square degrees we have a wonderful variety of double stars and multiple stars1 so close and delicate as to test the powers of the best telescopes1 besides a profusion of star-clusters and nebul1 including one of the supreme marvels of space1 the ,great ,nebula in the ,sword4 ,illustration3 ,,map ,,no4 #a4 ,our star map ,no4 #a will serve as a guide to the objects which we are about to inspect4 ,let us begin operations with our smallest telescope1 the three-inch4 ,i may remark here that1 just as the lowest magnifying power that will clearly reveal the object looked for gives ordinarily better results than a higher power1 so the smallest telescope that is competent to show what one wishes to see is likely to yield more satisfaction1 as far as that particular object is concerned1 than a larger glass4 ,the larger the object glass and the higher the power1 the greater are the atmospheric difficulties4 ,a small telescope will perform very well on a night when a large one is helpless4 ,turn the glass upon beta 7,rigel71 the white first-magnitude star in ,orion's left foot4 ,observe whether the image with a high power is clear1 sharp1 and free from irregular wisps of stray light4 ,look at the rings in and out of focus1 and if you are satisfied with the performance1 try for the companion4 ,a good three-inch is certain to show it1 except in a bad state of the atmosphere1 and even then an expert can see it1 at least by glimpses4 ,the companion is of the ninth magnitude1 some say the eighth1 and the distance is about #i4e1 angle of position 7hereafter designated by p47 #aii4a ,its color is blue1 in decided contrast with the white light of its great primary4 ,sir ,john ,herschel1 however1 saw the companion red1 as others have done4 ,these differences are doubtless due to imperfections of the eye or the telescope4 ,in #ahga ,burnham believed he had discovered that the companion was an exceedingly close double star4 ,no one except ,burnham himself succeeded in dividing it1 and he could only do so at times4 ,afterward1 when he was at ,mount ,hamilton1 he tried in vain to split it with the great thirty-six-inch telescope1 in #ahhi1 #ahij1 and #ahia4 ,his want of success induced him to suggest that the component stars were in rapid motion1 and so1 although he admitted that it might not be double after all1 he advised that it should be watched for a few years longer4 ,his confidence was justified1 for in #ahih ,aitken1 with the ,lick telescope1 saw and measured the distance of the extremely minute companion--distance #j4ag1 p4 #agg4 #a ,the angle of position measures the inclination to the meridian of a line drawn between the principal star and its companion2 in other words1 it shows in what direction from the primary we must look for the companion4 ,it is reckoned from #j up to #cfj1 beginning at the north point and passing around by east through south and west to north again4 ,thus1 if the angle of position is #j or #cfj1 the companion is on the north side of the primary2 if the angle is #ij1 the companion is to the east2 if #ahj1 to the south2 if #bgj1 to the west1 and so for intermediate angles4 ,it must be remembered1 however1 that in the field of the telescope the top is south and the bottom north1 unless a prism is used1 when directions become complicated4 ,east and west can be readily identified by noticing the motion of a star through the field2 it moves toward the west and from the east4 ,rigel has been suspected of a slight degree of variability4 ,it is evidently a star of enormous actual magnitude1 for its parallax escapes trustworthy measurement4 ,it can only be ranked among the very first of the light-givers of the visible universe4 ,spectroscopically it belongs to a peculiar type which has very few representatives among the bright stars1 and which has been thus described3 ,spectra in which the hydrogen lines and the few metallic lines all appear to be of equal breadth and sharp definition4 ,rigel shows a line which some believe to represent magnesium2 but while it has iron lines in its spectrum1 it exhibits no evidence of the existence of any such cloud of volatilized iron as that which helps to envelop the sun4 ,for another test of what the three-inch will do turn to zeta1 the lower1 or left-hand1 star in the ,belt4 ,this is a triple1 the magnitudes being second1 sixth1 and tenth4 ,the sixth-magnitude star is about #b4e from the primary1 p4 #adi1 and has a very peculiar color1 hard to describe4 ,it requires careful focusing to get a satisfactory view of this star with a three-inch telescope4 ,use magnifying powers up to two hundred and fifty diameters4 ,with our four-inch the star is much easier1 and the five-inch shows it readily with a power of one hundred4 ,the tenth-magnitude companion is distant #ef1 p4 #h1 and may be glimpsed with the three-inch4 ,upon the whole1 we shall find that we get more pleasing views of zeta ,orionis with the four-inch glass4 ,just to the left of zeta1 and in the same field of view with a very low power1 is a remarkable nebula bearing the catalogue number #abbg4 ,we must use our five-inch on this with a low power1 but with zeta out of the field in order to avoid its glare4 ,the nebula is exceedingly faint1 and we can be satisfied if we see it simply as a hazy spot1 although with much larger telescopes it has appeared at least half a degree broad4 ,tempel saw several centers of condensation in it1 and traced three or four broad nebulous streams1 one of which decidedly suggested spiral motion4 ,the upper star in the ,belt1 delta1 is double2 distance1 #ec1 p4 #cfj2 magnitudes1 second and seventh very nearly2 colors1 white and green or blue4 ,this1 of course1 is an easy object for the three-inch with a low magnifying power4 ,it would be useless to look for the two fainter companions of delta1 discovered by ,burnham1 even with our five-inch glass4 ,but we shall probably need the five-inch for our next attempt1 and it will be well to put on a high power1 say three hundred diameters4 ,the star to be examined is the little brilliant dangling below the right-hand end of the ,belt1 toward ,rigel4 ,it appears on the map as eta4 ,spare no pains in getting an accurate focus1 for here is something worth looking at1 and unless you have a trained eye you will not easily see it4 ,the star is double1 magnitudes third and sixth1 and the distance from center to center barely exceeds #a1 p4 #hg4 ,a little tremulousness of the atmosphere for a moment conceals the smaller star1 although its presence is manifest from the peculiar jutting of light on one side of the image of the primary4 ,but in an instant the disturbing undulations pass1 the air steadies1 the image shrinks and sharpens1 and two points of piercing brightness1 almost touching one another1 dart into sight1 the more brilliant one being surrounded by an evanescent circle1 a tiny ripple of light1 which1 as it runs round the star and then recedes1 alternately embraces and releases the smaller companion4 ,the wash of the light-waves in the atmosphere provokes many expressions of impatience from the astronomer1 but it is often a beautiful phenomenon nevertheless4 ,between eta and delta is a fifth-magnitude double star1 ,sigma #gbe1 which is worth a moment's attention4 ,the primary1 of a reddish color1 has a very faint star1 eleventh magnitude1 at a distance of #ab4g1 p4 #hh4 ,still retaining the five-inch in use1 we may next turn to the other end of the ,belt1 where1 just under zeta1 we perceive the fourth-magnitude star sigma4 ,he must be a person of indifferent mind who1 after looking with unassisted eyes at the modest glimmering of this little star1 can see it as the telescope reveals it without a thrill of wonder and a cry of pleasure4 ,the glass1 as by a touch of magic1 changes it from one into eight or ten stars4 ,there are two quadruple sets three and a half minutes of arc apart4 ,the first set exhibits a variety of beautiful colors4 ,the largest star1 of fourth magnitude1 is pale gray2 the second in rank1 seventh magnitude1 distance #db1 p4 #fa1 presents a singular red1 grape-red ,webb calls it2 the third1 eighth magnitude1 distance #ab1 p4 #hd1 is blue2 and the fourth1 eleventh magnitude1 distance #ab1 p4 #bcf1 is apparently white4 ,burnham has doubled the fourth-magnitude star1 distance #j4bc4 ,the second group of four stars consists of three of the eighth to ninth magnitude1 arranged in a minute triangle with a much fainter star near them4 ,between the two quadruple sets careful gazing reveals two other very faint stars4 ,while the five-inch gives a more satisfactory view of this wonderful multiple star than any smaller telescope can do1 the four-inch and even the three-inch would have shown it to us as a very beautiful object4 ,however we look at them1 there is an appearance of association among these stars1 shining with their contrasted colors and their various degrees of brilliance1 which is significant of the diversity of conditions and circumstances under which the suns and worlds beyond the solar walk exist4 ,from sigma let us drop down to see the wonders of ,orion's ,sword displayed just beneath4 ,we can use with advantage any one of our three telescopes2 but since we are going to look at a nebula1 it is fortunate that we have a glass so large as five inches aperture4 ,it will reveal interesting things that escape the smaller instruments1 because it grasps more than one and a half times as much light as the four-inch1 and nearly three times as much as the three-inch2 and in dealing with nebul a plenty of light is the chief thing to be desired4 ,the middle star in the ,sword is theta1 and is surrounded by the celebrated ,nebula of ,orion4 ,the telescope shows theta separated into four stars arranged at the corners of an irregular square1 and shining in a black gap in the nebula4 ,these four stars are collectively named the ,trapezium4 ,the brightest is of the sixth magnitude1 the others are of the seventh1 seven and a half1 and eighth magnitudes respectively4 ,the radiant mist about them has a faint greenish tinge1 while the four stars1 together with three others at no great distance1 which follow a fold of the nebula like a row of buttons on a coat1 always appear to me to show an extraordinary liveliness of radiance1 as if the strange haze served to set them off4 ,illustration3 ,,the ,,trapezium ,,with ,,the ,,fifth ,,and ,,sixth ,,stars4 ,our three-inch would have shown the four stars of the ,trapezium perfectly well1 and the four-inch would have revealed a fifth star1 very faint1 outside a line joining the smallest of the four and its nearest neighbor4 ,but the five-inch goes a step farther and enables us1 with steady gazing to see even a sixth star1 of only the twelfth magnitude1 just outside the ,trapezium1 near the brightest member of the quartet4 ,the ,lick telescope has disclosed one or two other minute points of light associated with the ,trapezium4 ,but more interesting than the ,trapezium is the vast cloud1 full of strange shapes1 surrounding it4 ,nowhere else in the heavens is the architecture of a nebula so clearly displayed4 ,it is an unfinished temple whose gigantic dimensions1 while exalting the imagination1 proclaim the omnipotence of its builder4 ,but though unfinished it is not abandoned4 ,the work of creation is proceeding within its precincts4 ,there are stars apparently completed1 shining like gems just dropped from the hand of the polisher1 and around them are masses1 eddies1 currents1 and swirls of nebulous matter yet to be condensed1 compacted1 and constructed into suns4 ,it is an education in the nebular theory of the universe merely to look at this spot with a good telescope4 ,if we do not gaze at it long and wistfully1 and return to it many times with unflagging interest1 we may be certain that there is not the making of an astronomer in us4 ,before quitting the ,orion nebula do not fail to notice an eighth-magnitude star1 a short distance northeast of the ,great ,nebula1 and nearly opposite the broad opening in the latter that leads in toward the gap occupied by the ,trapezium4 ,this star is plainly enveloped in nebulosity1 that is unquestionably connected with the larger mass of which it appears to form a satellite4 ,at the lower end of the ,sword is the star iota1 somewhat under the third magnitude4 ,our three-inch will show that it has a bluish companion of seventh or eighth magnitude1 at a little more than #aa distance1 p4 #adb1 and the larger apertures will reveal a third star1 of tenth magnitude1 and reddish in color1 distance #di1 p4 #ajc4 ,close by iota we find the little double star ,sigma #gdg1 whose components are of five and a half and six and a half magnitudes respectively1 and separated #cf1 p4 #bbc4 ,above the uppermost star in the ,sword is a small star cluster1 ,no4 #aahd1 which derives a special interest from the fact that it incloses a delicate double star1 ,sigma #gej1 whose larger component is of the sixth magnitude1 while the smaller is of the ninth1 and the distance is only #d4c1 p4 #ei4 ,we may try the four-inch on this object4 ,having looked at alpha 7,betelgeuse71 the great topaz star on ,orion's right shoulder1 and admired the splendor of its color1 we may turn the four-inch upon the star ,sigma #gie1 frequently referred to by its number as #eb ,orionis4 ,it consists of one star of the sixth and another of sixth and a half magnitude1 only #a4e apart1 p4 #bjj4 ,having separated them with a power of two hundred and fifty diameters on the four-inch1 we may try them with a high power on the three-inch4 ,we shall only succeed this time if our glass is of first-rate quality and the air is perfectly steady4 ,the star lambda in ,orion's head presents an easy conquest for the three-inch1 as it consists of a light-yellow star of magnitude three and a half and a reddish companion of the sixth magnitude2 distance #d1 p4 #dc4 ,there is also a twelfth-magnitude star at #bg1 p4 #ahc1 and a tenth or eleventh magnitude one at #adi1 p4 #bgh4 ,these are tests for the five-inch1 and we must not be disappointed if we do not succeed in seeing the smaller one even with that aperture4 ,other objects in ,orion1 to be found with the aid of our map1 are3 ,sigma #fbg1 a double star1 magnitude six and a half and seven1 distance #ba1 p4 #bfj2 ,omicron ,sigma #ih1 otherwise named iota ,orionis1 double1 magnitude six and seven1 distance #a1 p4 #ahj1 requires five-inch glass2 ,sigma #feb1 double1 magnitudes six and a half and eight1 distance #a4g1 p4 #ahd2 rho1 double1 magnitudes five and eight and a half1 the latter blue1 distance #g1 p4 #fb1 may be tried with a three-inch2 tau1 triple star1 magnitudes four1 ten and a half1 and eleven1 distances #cf1 p4 #bdi1 and #cf1 p4 #fj4 ,burnham discovered that the ten-and-a-half magnitude star is again double1 distance #d1 p4 #ej4 ,there is not much satisfaction in attempting tau ,orionis with telescopes of ordinary apertures2 ,sigma #fbi otherwise m ,orionis1 double1 magnitudes five and a half 7greenish7 and seven1 distance #ca4g1 p4 #bh1 a pretty object2 ,sigma #gbh1 otherwise ,a #cb1 double1 magnitudes five and seven1 distance1 #j4e or less1 p4 #bjf1 a rapid binary1#b which is at present too close for ordinary telescopes1 although it was once within their reach2 ,sigma #gbi1 double1 magnitudes six and eight1 distance #b1 p4 #bf1 the smaller star pale blue--try it with a four-inch1 but five-inch is better2 ,sigma #haf1 double1 magnitudes six and half and eight and a half1 distance #d1 p4 #bhi2 psi #b1 double1 magnitudes five and a half and eleven1 distance #c1 or a little less1 p4 #cbb2 #ije1 star cluster1 contains about twenty stars from the eighth to the eleventh magnitude2 #abfg1 nebula1 faint1 containing a triple star of the eighth magnitude1 two of whose components are #ea apart1 while the third is only #a4g from its companion1 p4 #he2 #acgf1 star cluster1 small and crowded2 #acfa1 star cluster1 triangular shape1 containing thirty stars1 seventh to tenth magnitudes1 one of which is a double1 distance #b4d4 #b ,the term binary is used to describe double stars which are in motion about their common center of gravity4 ,let us now leave the inviting star-fields of ,orion and take a glance at the little constellation of ,lepus1 crouching at the feet of the mythical giant4 ,we may begin with a new kind of object1 the celebrated red variable ,r ,leporis 7map ,no4 #a74 ,this star varies from the sixth or seventh magnitude to magnitude eight and a half in a period of four hundred and twenty-four days4 ,hind's picturesque description of its color has frequently been quoted4 ,he said it is of the most intense crimson1 resembling a blood-drop on the black ground of the sky4 ,it is important to remember that this star is reddest when faintest1 so that if we chance to see it near its maximum of brightness it will not impress us as being crimson at all1 but rather a dull1 coppery red4 ,its spectrum indicates that it is smothered with absorbing vapors1 a sun near extinction which1 at intervals1 experiences an accession of energy and bursts through its stifling envelope with explosive radiance1 only to faint and sink once more4 ,it is well to use our largest aperture in examining this star4 ,we may also employ the five-inch for an inspection of the double star iota1 whose chief component of the fifth magnitude is beautifully tinged with green4 ,the smaller companion is very faint1 eleventh magnitude1 and the distance is about #ac1 p4 #ccg4 ,another fine double in ,lepus is kappa1 to be found just below iota2 the components are of the fifth and eighth magnitudes1 pale yellow and blue respectively1 distance #b4e1 p4 #cfj2 the third-magnitude star alpha has a tenth-magnitude companion at a distance of #ce1 p4 #aef1 and its neighbor beta 7map ,no4 #b71 according to ,burnham1 is attended by three eleventh-magnitude stars1 two of which are at distances of #bjf1 p4 #ge1 and #bdj1 p4 #eh1 respectively1 while the third is less than #c from beta1 p4 #bhh2 the star gamma 7map ,no4 #b7 is a wide double1 the distance being #id1 and the magnitudes four and eight4 ,the star numbered #de is a remarkable multiple1 but the components are too faint to possess much interest for those who are not armed with very powerful telescopes4 ,illustration3 ,,map ,,no4 #b4 ,from ,lepus we pass to ,canis ,major 7map ,no4 #b74 ,there is no hope of our being able to see the companion of alpha 7,sirius71 at present 7#aija71 even with our five-inch4 ,discovered by ,alvan ,clark with an eighteen-inch telescope in #ahfb1 when its distance was #aj from the center of ,sirius1 this ninth-magnitude star has since been swallowed up in the blaze of its great primary4 ,at first1 it slightly increased its distance1 and from #ahfh until #ahgi most of the measures made by different observers considerably exceeded #aa4 ,then it began to close up1 and in #ahij the distance scarcely exceeded #d4 ,burnham was the last to catch sight of it with the ,lick telescope in that year4 ,after that no human eye saw it until #ahif1 when it was rediscovered at the ,lick ,observatory4 ,since then the distance has gradually increased to nearly #e4 ,according to ,burnham1 its periodic time is about fifty-three years1 and its nearest approach to ,sirius should have taken place in the middle of #ahib4 ,later calculations reduce the periodic time to forty-eight or forty-nine years4 ,if we can not see the companion of the ,dog ,star with our instruments1 we can at least1 while admiring the splendor of that dazzling orb1 reflect with profit upon the fact that although the companion is ten thousand times less bright than ,sirius1 it is half as massive as its brilliant neighbor4 ,imagine a subluminous body half as ponderous as the sun to be set revolving round it somewhere between ,uranus and ,neptune4 ,remember that that body would possess one hundred and sixty-five thousand times the gravitating energy of the earth1 and that five hundred and twenty ,jupiters would be required to equal its power of attraction1 and then consider the consequences to our easy-going planets6 ,plainly the solar system is not cut according to the ,sirian fashion4 ,we shall hardly find a more remarkable coupling of celestial bodies until we come1 on another evening1 to a star that began1 ages ago1 to amaze the thoughtful and inspire the superstitious with dread--the wonderful ,algol in ,perseus4 ,we may remark in passing that ,sirius is the brightest representative of the great spectroscopic type ,i1 which includes more than half of all the stars yet studied1 and which is characterized by a white or bluish-white color1 and a spectrum possessing few or at best faint metallic lines1 but remarkably broad1 black1 and intense lines of hydrogen4 ,the inference is that ,sirius is surrounded by an enormous atmosphere of hydrogen1 and that the intensity of its radiation is greater1 surface for surface1 than that of the sun4 ,there is historical evidence to support the assertion1 improbable in itself1 that ,sirius1 within eighteen hundred years1 has changed color from red to white4 ,with either of our telescopes we shall have a feast for the eye when we turn the glass upon the star cluster ,no4 #aded1 some four degrees south of ,sirius4 ,look for a red star near the center4 ,observe the curving rows so suggestive of design1 or rather of the process by which this cluster was evolved out of a pre-existing nebula4 ,you will recall the winding streams in the ,great ,nebula of ,orion4 ,another star cluster worth a moment's attention is ,no4 #adgi1 above and to the left of ,sirius4 ,we had better use the five-inch for this1 as many of the stars are very faint4 ,not far away we find the double star 1 whose components are of the fifth and eighth magnitudes1 distance #b4h1 p4 #cdc4 ,the small star is pale blue4 ,cluster ,no4 #aeab is a pleasing object with our largest aperture4 ,in ,no4 #aeaa we have a faint nebula remarkable for the rows of minute stars in and near it4 ,the star gamma is an irregular variable4 ,in #afgj it is said to have almost disappeared1 while at the beginning of the eighteenth century it was more than twice as bright as it is to-day4 ,the reddish star delta is also probably variable4 ,in my ,astronomy with an ,opera ,glass will be found a cut showing a singular array of small stars partly encircling delta4 ,these are widely scattered by a telescope1 even with the lowest power4 ,eastward from ,canis ,major we find some of the stars of ,argo ,navis4 ,sigma #ajig1 of the sixth magnitude1 has two minute companions at #bj distance1 p4 #caa and #cab4 ,the large star is itself double1 but the distance1 #j4h1 p4 #aff1 places it beyond our reach4 ,according to ,burnham1 there is yet a fourth faint star at #ca1 p4 #dj4 ,some three degrees and a half below and to the left of the star just examined is a beautiful star cluster1 ,no4 #aeea4 ,nos4 #aefd1 #aega1 and #afcj are other star clusters well worth examination4 ,a planetary nebula is included in #aefd4 ,with very powerful telescopes this nebula has been seen ring-shaped4 ,sigma #aadf1 otherwise known as #e ,navis1 is a pretty double1 colors pale yellow and blue1 magnitudes five and seven1 distance #c4be1 p4 #ai4 ,our three-inch will suffice for this4 ,illustration3 ,,map ,,no4 #c4 ,north of ,canis ,major and ,argo we find ,monoceros and ,canis ,minor 7map ,no4 #c74 ,the stars forming the western end of ,monoceros are depicted on map ,no4 #a4 ,we shall begin with these4 ,the most interesting and beautiful is #aa1 a fine triple star1 magnitudes five1 six1 and seven1 distances #g4d1 p4 #aca1 and #b4g1 p4 #ajc4 ,sir ,william ,herschel regarded this as one of the most beautiful sights in the heavens4 ,it is a good object to try our three-inch on1 although it should not be difficult for such an aperture4 ,the star #d is also a triple1 magnitudes six1 ten1 and eleven1 distances #c4d1 p4 #agh1 and #aj1 p4 #bdd4 ,we should glance at the star #e to admire its fine orange color4 ,in #h we find a golden fifth-magnitude star1 combined with a blue or lilac star of the seventh magnitude1 distance #ad1 p4 #bd4 ,sigma #ich is a difficult double1 magnitudes six and a half and twelve1 distance #aj1 p4 #baj4 ,sigma #iba is double1 magnitudes six and a half and eight1 distance #af1 p4 #d4 ,at the spot marked on the map #adbd we find an interesting cluster containing one star of the sixth magnitude4 ,the remaining stars of ,monoceros will be found on map ,no4 #c4 ,the double and triple stars to be noted are ,s1 or ,sigma #iej 7which is also a variable and involved in a faint nebula71 magnitudes six and nine1 distance #b4e1 p4 #bjf2 ,sigma #aahc1 double1 magnitudes five and a half and eight1 distance #ca1 p4 #cbf2 ,sigma #aaij1 triple1 magnitudes five and a half1 ten1 and nine1 distances #ca1 p4 #aje1 and #fg1 p4 #bdd4 ,the clusters are #adfe1 which has a minute triple star near the center2 #adhc1 one member of whose swarm is red2 #afaa1 very small but rich2 and #afcg1 interesting for the great number of ninth-magnitude stars that it contains4 ,we should use the five-inch for all of these4 ,canis ,minor and the ,head of ,hydra are also contained on map ,no4 #c4 ,procyon1 alpha of ,canis ,minor1 has several minute stars in the same field of view4 ,there is1 besides1 a companion which1 although it was known to exist1 no telescope was able to detect until ,november1 #ahif4 ,it must be of immense mass1 since its attraction causes perceptible perturbations in the motion of ,procyon4 ,its magnitude is eight and a half1 distance #d4hc1 p4 #cch4 ,one of the small stars just referred to1 the second one east of ,procyon1 distant one third of the moon's diameter1 is an interesting double4 ,our four-inch may separate it1 and the five-inch is certain to do so4 ,the magnitudes are seven and seven and a half or eight1 distance #a4b1 p4 #acc4 ,this star is variously named ,sigma #aabf and #ca ,can4 ,min4 ,bode4 ,star ,no4 #ad is a wide triple1 magnitudes six1 seven1 and eight1 distances #ge1 p4 #fe1 and #aae1 p4 #aed4 ,,procyon ,,and ,,its ,,neighbors4 ,in the ,head of ,hydra we find ,sigma #abde1 a double of the sixth and seventh magnitudes1 distance #aj4e1 p4 #be4 ,the larger star shows a fine yellow4 ,in epsilon we have a beautiful combination of a yellow with a blue star1 magnitudes four and eight1 distance #c4d1 p4 #aih4 ,finally1 let us look at theta for a light test with the five-inch4 ,the two stars composing it are of the fourth and twelfth magnitudes1 distance #ej1 p4 #agj4 ,the brilliant constellations of ,gemini and ,taurus tempt us next1 but warning clouds are gathering1 and we shall do well to house our telescopes and warm our fingers by the winter fire4 ,there will be other bright nights1 and the stars are lasting4 ,,chapter ,,iii ,,from ,,gemini ,,to ,,leo ,,and ,,round ,,about ,if thou wouldst gaze on starry ,charioteer1 ,and hast heard legends of the wondrous ,goat1 ,vast looming shalt thou find on the ,twins' left1 ,his form bowed forward4--,,poste',s ,,aratus4 ,illustration3 ,,map ,,no4 #d4 ,the zodiacal constellations of ,gemini1 ,cancer1 and ,leo1 together with their neighbors ,auriga1 the ,lynx1 ,hydra1 ,sextans1 and ,coma ,berenices1 will furnish an abundance of occupation for our second night at the telescope4 ,we shall begin1 using our three-inch glass1 with alpha1 the chief star of ,gemini 7map ,no4 #d74 ,this is ordinarily known as ,castor4 ,even an inexperienced eye perceives at once that it is not as bright as its neighbor ,pollux1 beta4 ,whether this fact is to be regarded as indicating that ,castor was brighter than ,pollux in #afjc1 when ,bayer attached their ,greek letters1 is still an unsettled question4 ,castor may or may not be a variable1 but it is1 at any rate1 one of the most beautiful double stars in the heavens4 ,a power of one hundred is amply sufficient to separate its components1 whose magnitudes are about two and three1 the distance between them being #f1 p4 #bbf4 ,a slight yet distinct tinge of green1 recalling that of the ,orion nebula1 gives a peculiar appearance to this couple4 ,green is one of the rarest colors among the stars4 ,castor belongs to the same general spectroscopic type in which ,sirius is found1 but its lines of hydrogen are broader than those seen in the spectrum of the ,dog ,star4 ,there is reason for thinking that it may be surrounded with a more extensive atmosphere of that gaseous metal called hydrogen than any other bright star possesses4 ,there seems to be no doubt that the components of ,castor are in revolution around their common center of gravity1 although the period is uncertain1 varying in different estimates all the way from two hundred and fifty to one thousand years2 the longer estimate is probably not far from the truth4 ,there is a tenth-magnitude star1 distance #gc1 p4 #afd1 which may belong to the same system4 ,from ,castor let us turn to ,pollux1 at the same time exchanging our three-inch telescope for the four-inch1 or1 still better1 the five-inch4 ,pollux has five faint companions1 of which we may expect to see three1 as follows3 ,tenth magnitude1 distance #age1 p4 #gj2 nine and a half magnitude1 distance #bjf1 p4 #ij1 and ninth magnitude1 distance #bbi1 p4 #ge4 ,burnham has seen a star of thirteen and a half magnitude1 distance #dc1 p4 #bge1 and has divided the tenth-magnitude star into two components1 only #a4d apart1 the smaller being of the thirteenth magnitude1 and situated at the angle #abh4 ,a calculation based on ,dr4 ,elkin's parallax of #j4jfh for ,pollux shows that that star may be a hundredfold more luminous than the sun1 while its nearest companion may be a body smaller than our planet ,jupiter1 but shining1 of course1 by its own light4 ,its distance from ,pollux1 however1 exceeds that of ,jupiter from the sun in the ratio of about one hundred and thirty to one4 ,in the double star pi we shall find a good light test for our three-inch aperture1 the magnitudes being six and eleven1 distance #bb1 p4 #bab4 ,the four-inch will show that kappa is a double1 magnitudes four and ten1 distance #f1 p4 #bcb4 ,the smaller star is of a delicate blue color1 and it has been suspected of variability4 ,that it may be variable is rendered the more probable by the fact that in the immediate neighborhood of kappa there are three undoubted variables1 ,s1 ,t1 and ,u1 and there appears to be some mysterious law of association which causes such stars to group themselves in certain regions4 ,none of the variables just named ever become visible to the naked eye1 although they all undergo great changes of brightness1 sinking from the eighth or ninth magnitude down to the thirteenth or even lower4 ,the variable ,r1 which lies considerably farther west1 is well worth attention because of the remarkable change of color which it sometimes exhibits4 ,it has been seen blue1 red1 and yellow in succession4 ,it varies from between the sixth and seventh magnitudes to less than the thirteenth in a period of about two hundred and forty-two days4 ,not far away we find a still more curious variable zeta2 this is also an interesting triple star1 its principal component being a little under the third magnitude1 while one of the companions is of the seventh magnitude1 distance #ij1 p4 #cee1 and the other is of the eleventh magnitude or less1 distance #fe1 p4 #he4 ,we should hardly expect to see the fainter companion with the three-inch4 ,the principal star varies from magnitude three and seven tenths down to magnitude four and a half in a period of a little more than ten days4 ,illustration3 ,,wonderful ,,nebula ,,in ,,gemini 7#aecb74 ,with the four-or five-inch we get a very pretty sight in delta1 which appears split into a yellow and a purple star1 magnitudes three and eight1 distance #g1 p4 #bjf4 ,near delta1 toward the east1 lies one of the strangest of all the nebul4 7,see the figures #aecb on the map47 ,our telescopes will show it to us only as a minute star surrounded with a nebulous atmosphere1 but its appearance with instruments of the first magnitude is so astonishing and at the same time so beautiful that ,i can not refrain from giving a brief description of it as ,i saw it in #ahic with the great ,lick telescope4 ,in the center glittered the star1 and spread evenly around it was a circular nebulous disk1 pale yet sparkling and conspicuous4 ,this disk was sharply bordered by a narrow black ring1 and outside the ring the luminous haze of the nebula again appeared1 gradually fading toward the edge to invisibility4 ,the accompanying cut1 which exaggerates the brightness of the nebula as compared with the star1 gives but a faint idea of this most singular object4 ,if its peculiarities were within the reach of ordinary telescopes1 there are few scenes in the heavens that would be deemed equally admirable4 ,in the star eta we have another long-period variable1 which is also a double star2 unfortunately the companion1 being of only the tenth magnitude and distant less than #a from its third-magnitude primary1 is beyond the reach of our telescopes4 ,but eta points the way to one of the finest star clusters in the sky1 marked #acfj on the map4 ,the naked eye perceives that there is something remarkable in that place1 and the opera glass faintly reveals its distant splendors1 but the telescope fairly carries us into its presence4 ,its stars are innumerable1 varying from the ninth magnitude downward to the last limit of visibility1 and presenting a wonderful array of curves which are highly interesting from the point of view of the nebular origin of such clusters4 ,looking backward in time1 with that theory to guide us1 we can see spiral lines of nebulous mist occupying the space that now glitters with interlacing rows of stars4 ,it is certainly difficult to understand how such lines of nebula could become knotted with the nuclei of future stars1 and then gradually be absorbed into those stars2 and yet1 if such a process does not occur1 what is the meaning of that narrow nebulous streak in the ,pleiades along which five or six stars are strung like beads on a string8 ,the surroundings of this cluster1 #acfj1 as one sweeps over them with the telescope gradually drawing toward the nucleus1 have often reminded me of the approaches to such a city as ,london4 ,thicker and closer the twinkling points become1 until at last1 as the observers eye follows the gorgeous lines of stars trending inward1 he seems to be entering the streets of a brilliantly lighted metropolis4 ,other objects in ,gemini that we can ill miss are3 1 double1 magnitudes three and eleven1 distance #gc1 p4 #gf1 colors yellow and blue2 #ae1 double1 magnitudes six and eight1 distance #cc1 p4 #bje2 gamma1 remarkable for array of small stars near it2 #ch1 double1 magnitudes six and eight1 distance #f4e1 p4 #afb1 colors yellow and blue 7very pretty72 lambda1 double1 magnitudes four and eleven1 distance #aj1 p4 #cj1 color of larger star blue--try with the five-inch2 epsilon1 double1 magnitudes three and nine1 distance #aaj1 p4 #id4 ,from ,gemini we pass to ,cancer4 ,this constellation has no large stars1 but its great cluster ,prsepe 7#afha on map ,no4 #d7 is easily seen as a starry cloud with the naked eye4 ,with the telescope it presents the most brilliant appearance with a very low power4 ,it was one of the first objects that ,galileo turned to when he had completed his telescope1 and he wonderingly counted its stars1 of which he enumerated thirty-six1 and made a diagram showing their positions4 ,the most interesting star in ,cancer is zeta1 a celebrated triple4 ,the magnitudes of its components are six1 seven1 and seven and a half2 distances #a4ad1 p4 #f1 and #e4g1 p4 #aad4 ,we must use our five-inch glass in order satisfactorily to separate the two nearest stars4 ,the gravitational relationship of the three stars is very peculiar4 ,the nearest pair revolve around their common center in about fifty-eight years1 while the third star revolves with the other two1 around a center common to all three1 in a period of six or seven hundred years4 ,but the movements of the third star are erratic1 and inexplicable except upon the hypothesis advanced by ,seeliger1 that there is an invisible1 or dark1 star near it by whose attraction its motion is perturbed4 ,in endeavoring to picture the condition of things in zeta ,cancri we might imagine our sun to have a companion sun1 a half or a third as large as itself1 and situated within what may be called planetary distance1 circling with it around their center of gravity2 while a third sun1 smaller than the second and several times as far away1 and accompanied by a black or non-luminous orb1 swings with the first two around another center of motion4 ,there you would have an entertaining complication for the inhabitants of a system of planets6 ,other objects in ,cancer are3 ,sigma #abbc1 double star1 magnitudes six and six and a half1 distance #e1 p4 #bad2 ,sigma #abia1 double1 magnitudes both six1 distance #a4c1 p4 #cbh--;four-inch should split it2 iota1 double1 magnitudes four and a half and six and a half1 distance #cj1 p4 #cjh2 #ff1 double magnitudes six and nine1 distance #d4h1 p4 #acf2 ,sigma #acaa1 double1 magnitudes both about the seventh1 distance #g1 p4 #bjj2 #agab1 star cluster1 very beautiful with the five-inch glass4 ,illustration3 ,,map ,,no4 #e4 ,the constellation of ,auriga may next command our attention 7map ,no4 #e74 ,the calm beauty of its leading star ,capella awakens an admiration that is not diminished by the rivalry of ,orion's brilliants glittering to the south of it4 ,although ,capella must be an enormously greater sun than ours1 its spectrum bears so much resemblance to the solar spectrum that a further likeness of condition is suggested4 ,no close telescopic companion to ,capella has been discovered4 ,a ninth-magnitude companion1 distant #aei1 p4 #adf1 and two others1 one of twelfth magnitude at #gh1 p4 #cag1 the other of thirteenth magnitude at #abf1 p4 #ahc1 may be distant satellites of the great star1 but not planets in the ordinary sense1 since it is evident that they are self-luminous4 ,it is a significant fact that most of the first-magnitude stars have faint companions which are not so distant as altogether to preclude the idea of physical relationship4 ,but while ,capella has no visible companion1 ,campbell1 of the ,lick ,observatory1 has lately discovered that it is a conspicuous example of a peculiar class of binary stars only detected within the closing decade of the nineteenth century4 ,the nature of these stars1 called spectroscopic binaries1 may perhaps best be described while we turn our attention from ,capella to the second star in ,auriga beta 7,menkalina71 which not only belongs to the same class1 but was the first to be discovered4 ,neither our telescopes1 nor any telescope in existence1 can directly reveal the duplicity of beta ,aurig to the eye--i4 e41 we can not see the two stars composing it1 because they are so close that their light remains inextricably mingled after the highest practicable magnifying power has been applied in the effort to separate them4 ,but the spectroscope shows that the star is double and that its components are in rapid revolution around one another1 completing their orbital swing in the astonishingly short period of four days6 ,the combined mass of the two stars is estimated to be two and a half times the mass of the sun1 and the distance between them1 from center to center1 is about eight million miles4 ,the manner in which the spectroscope revealed the existence of two stars in beta ,aurig is a beautiful illustration of the unexpected and1 so to speak1 automatic application of an old principle in the discovery of new facts not looked for4 ,it was noticed at the ,harvard ,observatory that the lines in the photographed spectrum of beta ,aurig 7and of a few other stars to be mentioned later7 appeared single in some of the photographs and double in others4 ,investigation proved that the lines were doubled at regular intervals of about two days1 and that they appeared single in the interim4 ,the explanation was not far to seek4 ,it is known that all stars which are approaching us have their spectral lines shifted1 by virtue of their motion of approach1 toward the violet end of the spectrum1 and that1 for a similar reason1 all stars which are receding have their lines shifted toward the red end of the spectrum4 ,now1 suppose two stars to be revolving around one another in a plane horizontal1 or nearly so1 to the line of sight4 ,when they are at their greatest angular distance apart as seen from the earth one of them will evidently be approaching at the same moment that the other is receding4 ,the spectral lines of the first will therefore be shifted toward the violet1 and those of the second will be shifted toward the red4 ,then if the stars1 when at their greatest distance apart1 are still so close that the telescope can not separate them1 their light will be combined in the spectrum2 but the spectral lines1 being simultaneously shifted in opposite directions1 will necessarily appear to be doubled4 ,as the revolution of the stars continues1 however1 it is clear that their motion will soon cease to be performed in the line of sight1 and will become more and more athwart that line1 and as this occurs the spectral lines will gradually assume their normal position and appear single4 ,this is the sequence of phenomena in beta ,aurig4 ,and the same sequence is found in ,capella and in several other more or less conspicuous stars in various parts of the heavens4 ,such facts1 like those connecting rows and groups of stars with masses and spiral lines of nebula are obscure signboards1 indicating the opening of a way which1 starting in an unexpected direction1 leads deep into the mysteries of the universe4 ,southward from beta we find the star theta1 which is a beautiful quadruple4 ,we shall do best with our five-inch here1 although in a fine condition of the atmosphere the four-inch might suffice4 ,the primary is of the third magnitude2 the first companion is of magnitude seven and a half1 distance #b1 p4 #e2 the second1 of the tenth magnitude1 distance #de1 p4 #bib2 and the third1 of the tenth magnitude1 distance #abe1 p4 #cej4 ,we should look at the double ,sigma #faf with one of our larger apertures in order to determine for ourselves what the colors of the components are4 ,there is considerable diversity of opinion on this point4 ,some say the larger star is pale red and the smaller light blue2 others consider the color of the larger star to be greenish1 and some have even called it white4 ,the magnitudes are five and nine1 distance #f1 p4 #cej4 ,auriga contains several noteworthy clusters which will be found on the map4 ,the most beautiful of these is #abie1 in which about five hundred stars have been counted4 ,the position of the new star of #ahib1 known as ,nova ,aurig1 is also indicated on the map4 ,while this never made a brilliant appearance1 it gave rise to a greater variety of speculative theories than any previous phenomenon of the kind4 ,although not recognized until ,january #bd1 #ahib1 this star1 as photographic records prove1 was in existence on ,december #i1 #ahia4 ,at its brightest it barely exceeded magnitude four and a half1 and its maximum occurred within ten days after its first recognition4 ,when discovered it was of the fifth magnitude4 ,it was last seen in its original form with the ,lick telescope on ,april #bfth1 when it had sunk to the lowest limit of visibility4 ,to everybody's astonishment it reappeared in the following ,august1 and on the #agth of that month was seen shining with the light of a tenth-magnitude star1 but presenting the spectrum of a nebula6 ,its visual appearance in the great telescope was now also that of a planetary nebula4 ,its spectrum during the first period of its visibility had been carefully studied1 so that the means existed for making a spectroscopic comparison of the phenomenon in its two phases4 ,during the first period1 when only a stellar spectrum was noticed1 remarkable shiftings of the spectral lines occurred1 indicating that two and perhaps three bodies were concerned in the production of the light of the new star1 one of which was approaching the earth1 while the other or the others receded with velocities of several hundred miles per second6 ,on the revival in the form of a planetary nebula1 while the character of the spectrum had entirely changed1 evidences of rapid motion in the line of sight remained4 ,but what was the meaning of all this8 ,evidently a catastrophe of some kind had occurred out there in space4 ,the idea of a collision involving the transformation of the energy of motion into that of light and heat suggests itself at once4 ,but what were the circumstances of the collision8 ,did an extinguished sun1 flying blindly through space1 plunge into a vast cloud of meteoric particles1 and1 under the lashing impact of so many myriads of missiles1 break into superficial incandescence1 while the cosmical wrack through which it had driven remained glowing with nebulous luminosity8 ,such an explanation has been offered by ,seeliger4 ,or was ,vogel right when he suggested that ,nova ,aurig could be accounted for by supposing that a wandering dark body had run into collision with a system of planets surrounding a decrepit sun 7and therefore it is to be hoped uninhabited71 and that those planets had been reduced to vapor and sent spinning by the encounter1 the second outburst of light being caused by an outlying planet of the system falling a prey to the vagabond destroyer8 ,or some may prefer the explanation1 based on a theory of ,wilsing's1 that two great bodies1 partially or wholly opaque and non-luminous at their surfaces1 but liquid hot within1 approached one another so closely that the tremendous strain of their tidal attraction burst their shells asunder so that their bowels of fire gushed briefly visible1 amid a blaze of spouting vapors4 ,and yet ,lockyer thinks that there was no solid or semisolid mass concerned in the phenomenon at all1 but that what occurred was simply the clash of two immense swarms of meteors that had crossed one another's track4 ,well1 where nobody positively knows1 everybody has free choice4 ,in the meantime1 look at the spot in the sky where that little star made its appearance and underwent its marvelous transformation1 for1 even if you can see no remains of it there1 you will feel your interest in the problem it has presented1 and in the whole subject of astronomy1 greatly heightened and vivified1 as the visitor to the field of ,waterloo becomes a lover of history on the spot4 ,the remaining objects of special interest in ,auriga may be briefly mentioned3 #bf1 triple star1 magnitudes five1 eight1 and eleven1 distances #ab1 p4 #bfh1 and #bf1 p4 #aac2 #ad1 triple star1 magnitudes five1 seven and a half1 and eleven1 distances #ad1 p4 #bbd1 and #ab4f1 p4 #cdb1 the last difficult for moderate apertures2 lambda1 double1 magnitudes five and nine1 distance #aba1 p4 #ac2 epsilon1 variable1 generally of third magnitude1 but has been seen of only four and a half magnitude2 #da1 double1 magnitudes five and six1 distance #h1 p4 #ced2 #iif1 #ajfg1 #aaai1 and #aaff1 clusters all well worth inspection1 #aaai being especially beautiful4 ,the inconspicuous ,lynx furnishes some fine telescopic objects1 all grouped near the northwestern corner of the constellation4 ,without a six-inch telescope it would be a waste of time to attack the double star #d1 whose components are of sixth and eighth magnitudes1 distance #j4h1 p4 #ajc2 but its neighbor1 #e1 a fine triple1 is within our reach1 the magnitudes being six1 ten1 and eight1 distances #cj1 p4 #aci1 and #if1 p4 #bgb4 ,in #ab ,lyncis we find one of the most attractive of triple stars1 which in good seeing weather is not beyond the powers of a three-inch glass1 although we shall have a far more satisfactory view of it with the four-inch4 ,the components are of the sixth1 seventh1 and eighth magnitudes1 distances #a4d1 p4 #aag1 and #h4g1 p4 #cjd4 ,a magnifying power which just suffices clearly to separate the disks of the two nearer stars makes this a fine sight4 ,a beautiful contrast of colors belongs to the double star #ad1 but unfortunately the star is at present very close1 the distance between its sixth and seventh magnitude components not exceeding #j4h1 position angle #fd4 ,sigma #ieh is a pretty double1 both stars being of the sixth magnitude1 distance #e1 p4 #beg4 ,still finer is ,sigma #ajji1 a double1 whose stars are both a little above the seventh magnitude and nearly equal1 distance #c1 p4 #aef4 ,a low power suffices to show the three stars in #ai1 their magnitudes being six and a half1 seven and a half1 and eight1 distances #ae1 p4 #cab1 and #bae1 p4 #ceh4 ,webb describes the two smaller stars as plum-colored4 ,plum-colored suns6 ,at the opposite end of the constellation are two fine doubles1 ,sigma #accc1 magnitudes six and a half and seven1 distance #a4d1 p4 #ci2 and #ch1 magnitudes four and seven1 distance #b4i1 p4 #bce4 ,under the guidance of map ,no4 #f we turn to ,leo1 which contains one of the leading gems among the double stars1 gamma1 whose components1 of the second and fourth magnitudes1 are respectively yellow and green1 the green star1 according to some observers1 having a peculiar tinge of red4 ,their distance apart is #c4g1 p4 #aah1 and they are undoubtedly in revolution about a common center1 the probable period being about four hundred years4 ,the three-inch glass should separate them easily when the air is steady1 and a pleasing sight they are4 ,the star iota is a closer double1 and also very pretty1 magnitudes four and eight1 colors lemon and light blue1 distance #b4ag1 p4 #ec4 ,other doubles are tau1 magnitudes five and seven1 distance #ie1 p4 #agj2 #hh1 magnitudes seven and nine1 distance #ae1 p4 #cbj2 #ij1 triple1 magnitudes six1 seven and a half1 and ten1 distance1 #c4e1 p4 #bji1 and #ei1 p4 #bcd2 #ed1 magnitudes four and a half and seven1 distance #f4b1 p4 #ajb2 and #di1 magnitudes six and nine1 distance #b4d1 p4 #aeh4 ,leo contains a remarkable variable star1 ,r1 deep red in color1 and varying in a space of a hundred and forty-four days from the fifth to the tenth magnitude4 ,it has also several nebul1 of which only one needs special mention1 ,no4 #ahfa4 ,this is spindle-shaped1 and large telescopes show that it consists of three nebul4 ,the observer with ordinary instruments finds little to see and little to interest him in these small1 faint nebul4 ,we may just glance at two double stars in the small constellation of ,sextans1 situated under ,leo4 ,these are3 #i1 magnitudes seven and eight1 distance #ec1 p4 #bib2 and #ce1 magnitudes six and seven1 distance #f4i1 p4 #bdj4 ,illustration3 ,,map ,,no4 #f4 ,coma ,berenices 7map ,no4 #f7 includes several interesting objects4 ,let us begin with the star #b1 a double1 of magnitudes six and seven and a half1 distance #c4f1 p4 #bdj4 ,the color of the smaller star is lilac4 ,this hue1 although not extremely uncommon among double stars elsewhere1 recurs again and again1 with singular persistence1 in this little constellation4 ,for instance1 in the very next star that we look at1 #ab1 we find a double whose smaller component is lilac4 ,the magnitudes in #ab are five and eight1 distance #ff1 p4 #afh4 ,so also the wide double #ag1 magnitudes five and a half and six1 distance #ade1 exhibits a tinge of lilac in the smaller component2 the triple #ce1 magnitudes five1 eight1 and nine1 distances #a1 p4 #gg1 and #bh4g1 p4 #abd1 has four colors yellow1 lilac1 and blue1 and the double #bd1 magnitudes five and six1 distance #bj1 p4 #bgj1 combines an orange with a lilac star1 a very striking and beautiful contrast4 ,we should make a mistake if we regarded this wonderful distribution of color among the double stars as accidental4 ,it is manifestly expressive of their physical condition1 although we can not yet decipher its exact meaning4 ,the binary #db ,com ,berenicis is too close for ordinary telescopes1 but it is highly interesting as an intermediate between those pairs which the telescope is able to separate and those--like beta ,aurig--which no magnifying power can divide1 but which reveal the fact that they are double by the periodical splitting of their spectral lines4 ,the orbit in #db ,com ,berenicis is a very small one1 so that even when the components are at their greatest distance apart they can not be separated by a five-or six-inch glass4 ,burnham1 using the ,lick telescope1 in #ahij made the distance #j4g2 ,hall1 using the ,washington telescope1 in #ahia made it a trifle more than #j4e4 ,he had measured it in #ahhf as only #j4bg4 ,the period of revolution is believed to be about twenty-five years4 ,in ,coma ,berenices there is an outlying field of the marvelous nebulous region of ,virgo1 which we may explore on some future evening4 ,but the nebul in ,coma are very faint1 and1 for an amateur1 hardly worth the trouble required to pick them up4 ,the two clusters included in the map1 #bgeb and #cdec1 are bright enough to repay inspection with our largest aperture4 ,illustration3 ,,map ,,no4 #g4 ,although ,hydra is the largest constellation in the heavens1 extending about seven hours1 or #aje1 in right ascension1 it contains comparatively few objects of interest1 and most of these are in the head or western end of the constellation1 which we examined during our first night at the telescope4 ,in the central portion of ,hydra1 represented on map ,no4 #g1 we find its leading star alpha1 sometimes called ,alphard1 or ,cor ,hydr1 a bright second-magnitude star that has been suspected of variability4 ,it has a decided orange tint1 and is accompanied1 at a distance of #bha1 p4 #aec1 by a greenish tenth-magnitude star4 ,bu4 #cci is a fine double1 magnitudes eight and nine and a half1 distance #a4c1 p4 #baf4 ,the planetary nebula #bajb is about #a' in diameter1 pale blue in color1 and worth looking at1 because it is brighter than most objects of its class4 ,tempel and ,secchi have given wonderful descriptions of it1 both finding multitudes of stars intermingled with nebulous matter4 ,for a last glimpse at celestial splendors for the night1 let us turn to the rich cluster #afcj1 in ,argo1 just above the place where the stream of the ,milky ,way--here bright in mid-channel and shallowing toward the shores--separates into two or three currents before disappearing behind the horizon4 ,it is by no means as brilliant as some of the star clusters we have seen1 but it gains in beauty and impressiveness from the presence of one bright star that seems to captain a host of inferior luminaries4 ,,chapter ,,iv ,,virgo ,,and ,,her ,,neighbors 444 that region ,where still by night is seen ,the ,virgin goddess near to bright ,botes4--,,poste',s ,,aratus4 ,illustration3 ,,map ,,no4 #h4 ,following the order of right ascension1 we come next to the little constellations ,crater and ,corvus1 which may be described as standing on the curves of ,hydra 7map ,no4 #h74 ,beginning with ,crater1 let us look first at alpha1 a yellow fourth-magnitude star1 near which is a celebrated red variable ,r4 ,with a low power we can see both alpha and ,r in the same field of view1 like a very wide double4 ,there is a third star of ninth magnitude1 and bluish in color1 near ,r on the side toward alpha4 ,r is variable both in color and light4 ,when reddest1 it has been described as scarlet1 crimson1 and blood-colored2 when palest1 it is a deep orange-red4 ,its light variation has a period the precise length of which is not yet known4 ,the cycle of change is included between the eighth and ninth magnitudes4 ,while our three-inch telescope suffices to show ,r1 it is better to use the five-inch1 because of the faintness of the star4 ,when the color is well seen1 the contrast with alpha is very pleasing4 ,there is hardly anything else in ,crater to interest us1 and we pass over the border into ,corvus1 and go at once to its chief attraction1 the star delta4 ,the components of this beautiful double are of magnitudes three and eight2 distance #bd1 p4 #baa2 colors yellow and purple4 ,the night being dark and clear1 we take the five-inch and turn it on the nebula #cabh1 which the map shows just under the border of ,corvus in the edge of ,hydra4 ,herschel believed he had resolved this into stars4 ,it is a faint object and small1 not exceeding one eighth of the moon's diameter4 ,farther east in ,hydra1 as indicated near the left-hand edge of map ,no4 #h1 is a somewhat remarkable variable1 ,r ,hydr4 ,this star occasionally reaches magnitude three and a half1 while at minimum it is not much above the tenth magnitude4 ,its period is about four hundred and twenty-five days4 ,illustration3 ,,map ,,no4 #i4 ,while we have been examining these comparatively barren regions1 glad to find one or two colored doubles to relieve the monotony of the search1 a glittering white star has frequently drawn our eyes eastward and upward4 ,it is ,spica1 the great gem of ,virgo1 and1 yielding to its attraction1 we now enter the richer constellation over which it presides 7map ,no4 #i74 ,except for its beauty1 which every one must admire1 ,spica1 or alpha ,virginis1 has no special claim upon our attention4 ,some evidence has been obtained that1 like beta ,aurig and ,capella1 it revolves with an invisible companion of great mass in an orbit only six million miles in diameter4 ,spica's spectrum resembles that of ,sirius4 ,the faint star which our larger apertures show about #f' northeast of ,spica is of the tenth magnitude4 ,sweeping westward1 we come upon ,sigma #affi1 a pretty little double with nearly equal components of about the sixth magnitude1 distance #e4f1 p4 #abd4 ,but our interest is not fully aroused until we reach gamma1 a star with a history4 ,the components of this celebrated binary are both nearly of the third magnitude1 distance about #e4h1 p4 #aej4 ,they revolve around their common center in something less than two hundred years4 ,according to some authorities1 the period is one hundred and seventy years1 but it is not yet certainly ascertained4 ,it was noticed about the beginning of the seventeenth century that gamma ,virginis was double4 ,in #ahcf the stars were so close together that no telescope then in existence was able to separate them1 although it is said that the disk into which they had merged was elongated at ,pulkowa4 ,in a few years they became easily separable once more4 ,if the one-hundred-and-seventy-year period is correct1 they should continue to get farther apart until about #aiba4 ,according to ,asaph ,hall1 their greatest apparent distance is #f4c1 and their least apparent distance #j4e2 consequently1 they will never again close up beyond the separating power of existing telescopes4 ,there is a great charm in watching this pair of stars even with a three-inch telescope--not so much on account of what is seen1 although they are very beautiful1 as on account of what we know they are doing4 ,it is no slight thing to behold two distant stars obeying the law that makes a stone fall to the ground and compels the earth to swing round the sun4 ,in theta we discover a fine triple1 magnitudes four and a half1 nine1 and ten2 distances #g1 p4 #cde1 and #fe1 p4 #bie4 ,the ninth-magnitude star has been described as violet1 but such designations of color are often misleading when the star is very faint4 ,on the other hand it should not be assumed that a certain color does not exist because the observer can not perceive it1 for experience shows that there is a wide difference among observers in the power of the eye to distinguish color4 ,i have known persons who could not perceive the difference of hue in some of the most beautifully contrasted colored doubles to be found in the sky4 ,i am acquainted with an astronomer of long experience in the use of telescopes1 whose eye is so deficient in color sense that he denies that there are any decided colors among the stars4 ,such persons miss one of the finest pleasures of the telescope4 ,in examining theta ,virginis we shall do best to use our largest aperture1 viz41 the five-inch4 ,yet ,webb records that all three of the stars in this triple have been seen with a telescope of only three inches aperture4 ,the amateur must remember in such cases how much depends upon practice as well as upon the condition of the atmosphere4 ,there are lamentably few nights in a year when even the best telescope is ideally perfect in performance1 but every night's observation increases the capacity of the eye1 begetting a kind of critical judgment which renders it to some extent independent of atmospheric vagaries4 ,it will also be found that the idiosyncrasies of the observer are reflected in his instrument1 which seems to have its fits of excellence1 its inspirations so to speak1 while at other times it behaves as if all its wonderful powers had departed4 ,another double that perhaps we had better not try with less than four inches aperture is #hd ,virginis4 ,the magnitudes are six and nine2 distance1 #c4e1 p4 #bcc4 ,colors yellow and blue4 ,sigma #ahdf is a fifth-magnitude star with a tenth-magnitude companion1 distance only #d1 p4 #ajh4 ,use the five-inch4 ,and now we approach something that is truly marvelous1 the ,field of the ,nebul4 ,this strange region1 lying mostly in the constellation ,virgo1 is roughly outlined by the stars beta1 eta1 gamma1 delta1 and epsilon1 which form two sides of a square some #ae across4 ,it extends1 however1 for some distance into ,coma ,berenices1 while outlying nebul belonging to it are also to be found in the eastern part of ,leo4 ,unfortunately for those who expect only brilliant revelations when they look through a telescope1 this throng of nebul consists of small and inconspicuous wisps as ill defined as bits of thistle-down floating high in the air4 ,there are more than three hundred of them all told1 but even the brightest are faint objects when seen with the largest of our telescopes4 ,why do they congregate thus8 ,that is the question which lends an interest to the assemblage that no individual member of it could alone command4 ,it is a mystery1 but beyond question it is explicable4 ,the explanation1 however1 is yet to be discovered4 ,the places of only three of the nebul are indicated on the map4 ,no4 #bhjf has been described as resembling in shape a shuttle4 ,its length is nearly one third of the moon's diameter4 ,it is brightest near the center1 and has several faint companions4 ,no4 #bifa is round1 #d' in diameter1 and is accompanied by another round nebula in the same field of view toward the south4 ,no4 #caje is double1 and powerful telescopes show two more ghostly companions4 ,there is an opportunity for good and useful work in a careful study of the little nebul that swim into view all over this part of ,virgo4 ,celestial photography has triumphs in store for itself here4 ,scattered over and around the region where the nebul are thickest we find eight or nine variable stars1 three of the most remarkable of which1 ,r1 ,s1 and ,u1 may be found on the map4 ,r is very irregular1 sometimes attaining magnitude six and a half1 while at other times its maximum brightness does not exceed that of an eighth-magnitude star4 ,at minimum it sinks to the tenth or eleventh magnitude4 ,its period is one hundred and forty-five days4 ,u varies from magnitude seven or eight down to magnitude twelve or under and then regains its light1 in a period of about two hundred and seven days4 ,s is interesting for its brilliant red color4 ,when brightest1 it exceeds the sixth magnitude1 but at some of its maxima the magnitude is hardly greater than the eighth4 ,at minimum it goes below the twelfth magnitude4 ,period1 three hundred and seventy-six days4 ,illustration3 ,,map ,,no4 #aj4 ,next east of ,virgo is ,libra1 which contains a few notable objects 7map ,no4 #aj74 ,the star alpha has a fifth-magnitude companion1 distant about #bcj1 which can be easily seen with an opera glass4 ,at the point marked ,a on the map is a curious multiple star1 sometimes referred to by its number in ,piazzi's catalogues as follows3 #bab ,p4 xiv4 ,the two principal stars are easily seen1 their magnitudes being six and seven and a half2 distance #ae1 p4 #bij4 ,burnham found four other faint companions1 for which it would be useless for us to look4 ,the remarkable thing is that these faint stars1 the nearest of which is distant about #ej from the largest member of the group and the farthest about #abi1 do not share1 according to their discoverer1 in the rapid proper motion of the two main stars4 ,in iota we find a double a little difficult for our three-inch4 ,the components are of magnitudes four and a half and nine1 distance #eg1 p4 #aaj4 ,burnham discovered that the ninth-magnitude star consists of two of the tenth less than #b apart1 p4 #bd4 ,no astronomer who happens to be engaged in this part of the sky ever fails1 unless his attention is absorbed by something of special interest1 to glance at beta ,libr1 which is famous as the only naked-eye star having a decided green color4 ,the hue is pale1 but manifest4#c #c ,is the slight green tint perceptible in ,sirius variable8 ,i am sometimes disposed to think it is4 ,the star is a remarkable variable1 belonging to what is called the ,algol type4 ,its period1 according to ,chandler1 is #b days #g hours1 #ea minutes1 #bb4h seconds4 ,the time occupied by the actual changes is about twelve hours4 ,at maximum the star is of magnitude five and at minimum of magnitude #f4b4 ,illustration3 ,,map ,,no4 #aa4 ,we may now conveniently turn northward from ,virgo in order to explore ,botes1 one of the most interesting of the constellations 7map ,no4 #aa74 ,its leading star alpha1 ,arcturus1 is the brightest in the northern hemisphere4 ,its precedence over its rivals ,vega and ,capella1 long in dispute1 has been settled by the ,harvard photometry4 ,you notice that the color of ,arcturus1 when it has not risen far above the horizon1 is a yellowish red1 but when the star is near mid-heaven the color fades to light yellow4 ,the hue is possibly variable1 for it is recorded that in #aheb ,arcturus appeared to have nearly lost its color4 ,if it should eventually turn white1 the fact would have an important bearing upon the question whether ,sirius was1 as alleged1 once a red or flame-colored star4 ,but let us sit here in the starlight1 for the night is balmy1 and talk about ,arcturus1 which is perhaps actually the greatest sun within the range of terrestrial vision4 ,its parallax is so minute that the consideration of the tremendous size of this star is a thing that the imagination can not placidly approach4 ,calculations1 based on its assumed distance1 which show that it outshines the sun several thousand times1 may be no exaggeration of the truth6 ,it is easy to make such a calculation4 ,one of ,dr4 ,elkin's parallaxes for ,arcturus is #j4jah4 ,that is to say1 the displacement of ,arcturus due to the change in the observer's point of view when he looks at the star first from one side and then from the other side of the earth's orbit1 #ahf1jjj1jjj miles across1 amounts to only eighteen one-thousandths of a second of arc4 ,we can appreciate how small that is when we reflect that it is about equal to the apparent distance between the heads of two pins placed an inch apart and viewed from a distance of a hundred and eighty miles6 ,assuming this estimate of the parallax of ,arcturus1 let us see how it will enable us to calculate the probable size or light-giving power of the star as compared with the sun4 ,the first thing to do is to multiply the earth's distance from the sun1 which may be taken at #ic1jjj1jjj miles1 by #bjf1bfe1 the number of seconds of arc in a radian1 the base of circular measure1 and then divide the product by the parallax of the star4 ,performing the multiplication and division1 we get the following3 #ai1ahb1fde1jjj1jjj _/ 4#jah #a1jfe1gjb1ejj1jjj1jjj4 ,the quotient represents miles6 ,call it1 in round numbers1 a thousand millions of millions of miles4 ,this is about #aa1djj1jjj times the distance from the earth to the sun4 ,now for the second part of the calculation3 ,the amount of light received on the earth from some of the brighter stars has been experimentally compared with the amount received from the sun4 ,the results differ rather widely1 but in the case of ,arcturus the ratio of the star's light to sunlight may be taken as about one twenty-five-thousand-millionth--i4 e41 #be1jjj1jjj1jjj stars1 each equal to ,arcturus1 would together shed upon the earth as much light as the sun does4 ,but we know that light varies inversely as the square of the distance2 for instance1 if the sun were twice as far away as it is1 its light would be diminished for us to a quarter of its present amount4 ,suppose1 then1 that we could remove the earth to a point midway between the sun and ,arcturus1 we should then be #e1gjj1jjj times as far from the sun as we now are4 ,in order to estimate how much light the sun would send us from that distance we must square the number #e1gjj1jjj and then take the result inversely1 or as a fraction4 ,we thus get #a _/ #cb1dij1jjj1jjj1jjj1 representing the ratio of the sun's light at half the distance of ,arcturus to that at its real distance4 ,but while receding from the sun we should be approaching ,arcturus4 ,we should get1 in fact1 twice as near to that star as we were before1 and therefore its light would be increased for us fourfold4 ,now1 if the amount of sunlight had not changed1 it would exceed the light of ,arcturus only a quarter as much as it did before1 or in the ratio of #be1jjj1jjj1jjj _/ #d #f1bej1jjj1jjj to #a4 ,but1 as we have seen1 the sunlight would diminish through increase of distance to one #cb1dij1jjj1jjj1jjjth part of its original amount4 ,hence its altered ratio to the light of ,arcturus would become #f1bej1jjj1jjj to #cb1dij1jjj1jjj1jjj1 or #a to #e1aih4 ,this means that if the earth were situated midway between the sun and ,arcturus1 it would receive #e1aih times as much light from that star as it would from the sun6 ,it is quite probable1 moreover1 that the heat of ,arcturus exceeds the solar heat in the same ratio1 for the spectroscope shows that although ,arcturus is surrounded with a cloak of metallic vapors proportionately far more extensive than the sun's1 yet1 smothered as the great star seems in some respects to be1 it rivals ,sirius itself in the intensity of its radiant energy4 ,if we suppose the radiation of ,arcturus to be the same per unit of surface as the sun's1 it follows that ,arcturus exceeds the sun about #cge1jjj times in volume1 and that its diameter is no less than #fb1cej1jjj miles6 ,imagine the earth and the other planets constituting the solar system removed to ,arcturus and set revolving around it in orbits of the same forms and sizes as those in which they circle about the sun4 ,poor ,mercury6 ,for that little planet it would indeed be a jump from the frying pan into the fire1 because1 as it rushed to perihelion1 ,mercury would plunge more than #b1ejj1jjj miles beneath the surface of the giant star4 ,venus and the earth would melt like snowflakes at the mouth of a furnace4 ,even far-away ,neptune1 the remotest member of the system1 would swelter in torrid heat4 ,but stop6 ,look at the sky4 ,observe how small and motionless the disks of the stars have become4 ,back to the telescopes at once1 for this is a token that the atmosphere is steady1 and that good seeing may be expected4 ,it is fortunate1 for we have some delicate work before us4 ,the very first double star we try in ,botes1 ,sigma #aggb1 requires the use of the four-inch1 and the five-inch shows it more satisfactorily4 ,the magnitudes are sixth and ninth1 distance #e1 p4 #adj4 ,on the other side of ,arcturus we find zeta1 a star that we should have had no great difficulty in separating thirty years ago1 but which has now closed up beyond the reach even of our five-inch4 ,the magnitudes are both fourth1 and the distance less than a quarter of a second2 position angle changing4 ,it is apparently a binary1 and if so will some time widen again1 but its period is unknown4 ,the star #bgi1 also known as ,sigma #aiaj1 near the southeastern edge of the constellation1 is a pretty double1 each component being of the seventh magnitude1 distance #d1 p4 #bab4 ,just above zeta we come upon pi1 an easy double for the three-inch1 magnitudes four and six1 distance #f p4 #ii4 ,next is xi1 a yellow and purple pair1 whose magnitudes are respectively five and seven1 distance less than #c1 p4 #bjj4 ,this is undoubtedly a binary with a period of revolution of about a hundred and thirty years4 ,its distance decreased about #a between #ahha and #ahia4 ,it was still decreasing in #ahii1 when it had become #b4e4 ,the orbital swing is also very apparent in the change of the position angle4 ,the telescopic gem of ,botes1 and one of the flowers of the sky1 is epsilon1 also known as ,mirac4 ,when well seen1 as we shall see it to-night1 epsilon ,botis is superb4 ,the magnitudes of its two component stars are two and a half 7according to ,hall1 three7 and six4 ,the distance is about #b4h1 p4 #cbf4 ,the contrast of colors--bright orange yellow1 set against brilliant emerald green--is magnificent4 ,there are very few doubles that can be compared with it in this respect4 ,the three-inch will separate it1 but the five-inch enables us best to enjoy its beauty4 ,it appears to be a binary1 but the motion is very slow1 and nothing certain is yet known of its period4 ,in delta we have a very wide and easy double2 magnitudes three and a half and eight and a half1 distance #aaj1 p4 #ge4 ,the smaller star has a lilac hue4 ,we can not hope with any of our instruments to see all of the three stars contained in 1 but two of them are easily seen2 magnitudes four and seven1 distance #ajh1 p4 #agb4 ,the smaller star is again double2 magnitudes seven and eight1 distance #j4gg1 p4 #hh4 ,it is clearly a binary1 with a long period4 ,a six-inch telescope that could separate this star at present would be indeed a treasure4 ,sigma #aibf is another object rather beyond our powers1 on account of the contrast of magnitudes4 ,these are six and eight and a half2 distance #a4c1 p4 #bef4 ,other doubles are3 #dd 7,sigma #aiji71 magnitudes five and six1 distance #d4h1 p4 #bdj2 #ci 7,sigma #ahij71 magnitudes both nearly six1 distance #c4f1 p4 #de4 ,smaller star light red2 iota1 magnitudes four and a half and seven and a half1 distance #ch1 p4 #cc2 kappa1 magnitudes five and a half and eight1 distance #ab4g1 p4 #bch4 ,some observers see a greenish tinge in the light of the larger star1 the smaller one being blue4 ,there are one or two interesting things to be seen in that part of ,canes ,venatici which is represented on map ,no4 #aa4 ,the first of these is the star cluster #cicf4 ,this will reward a good look with the five-inch4 ,with large telescopes as many as one thousand stars have been discerned packed within its globular outlines4 ,the star #be 7,sigma #agfh7 is a close binary with a period estimated at one hundred and twenty-five years4 ,the magnitudes are six and seven or eight1 distance about #a1 p4 #acg4 ,we may try for this with the five-inch1 and if we do not succeed in separating the stars we may hope to do so some time1 for the distance between them is increasing4 ,although the nebula #cegb is a very wonderful object1 we shall leave it for another evening4 ,eastward from ,botes shines the circlet of ,corona ,borealis1 whose form is so strikingly marked out by the stars that the most careless eye perceives it at once4 ,although a very small constellation1 it abounds with interesting objects4 ,we begin our attack with the five-inch on ,sigma #aicb1 but not too confident that we shall come off victors1 for this binary has been slowly closing for many years4 ,the magnitudes are six and a half and seven1 distance #j4hd1 p4 #aej4 ,not far distant is another binary1 at present beyond our powers1 eta4 ,here the magnitudes are both six1 distance #j4fe1 p4 #c4 ,hall assigns a period of forty years to this star4 ,the assemblage of close binaries in this neighborhood is very curious4 ,only a few degrees away we find one that is still more remarkable1 the star gamma4 ,what has previously been said about #db ,com ,berenicis applies in a measure to this star also4 ,it1 too1 has a comparatively small orbit1 and its components are never seen widely separated4 ,in #ahbf their distance was #j4g2 in #ahhj they could not be split2 in #ahia the distance had increased to #j4cf1 and in #ahid it had become #j4ec1 p4 #abc4 ,but in #ahii ,lewis made the distance only #j4dc4 ,the period has been estimated at one hundred years4 ,while the group of double stars in the southern part of ,corona ,borealis consists1 as we have seen1 of remarkably close binaries1 another group in the northern part of the same constellation comprises stars that are easily separated4 ,let us first try zeta4 ,the powers of the three-inch are amply sufficient in this case4 ,the magnitudes are four and five1 distance #f4c1 p4 #cjj4 ,colors1 white or bluish-white and blue or green4 ,next take sigma1 whose magnitudes are five and six1 distance #d1 p4 #bjf4 ,with the five-inch we may look for a second companion of the tenth magnitude1 distance #ed1 p4 #hh4 ,it is thought highly probable that sigma is a binary1 but its period has simply been guessed at4 ,finally1 we come to nu1 which consists of two very widely separated stars1 nu#a and nu#b1 each of which has a faint companion4 ,with the five-inch we may be able to see the companion of nu#b1 the more southerly of the pair4 ,the magnitude of the companion is variously given as tenth and twelfth1 distance #acg1 p4 #ah4 ,with the aid of the map we find the position of the new star of #ahff1 which is famous as the first so-called temporary star to which spectroscopic analysis was applied4 ,when first noticed1 on ,may #ab1 #ahff1 this star was of the second magnitude1 fully equaling in brilliancy alpha1 the brightest star of the constellation2 but in about two weeks it fell to the ninth magnitude4 ,huggins and ,miller eagerly studied the star with the spectroscope1 and their results were received with deepest interest4 ,they concluded that the light of the new star had two different sources1 each giving a spectrum peculiar to itself4 ,one of the spectra had dark lines and the other bright lines4 ,it will be remembered that a similar peculiarity was exhibited by the new star in ,auriga in #ahic4 ,but the star in ,corona did not disappear4 ,it diminished to magnitude nine and a half or ten1 and stopped there2 and it is still visible4 ,in fact1 subsequent examination proved that it had been catalogued at ,bonn as a star of magnitude nine and a half in #ahee4 ,consequently this blaze star of #ahff will bear watching in its decrepitude4 ,nobody knows but that it may blaze again4 ,perhaps it is a sun-like body2 perhaps it bears little resemblance to a sun as we understand such a thing4 ,but whatever it may be1 it has proved itself capable of doing very extraordinary things4 ,we have no reason to suspect the sun of any latent eccentricities1 like those that have been displayed by temporary stars2 yet1 acting on the principle which led the old emperor-astrologer ,rudolph ,,ii to torment his mind with self-made horoscopes of evil import1 let us unscientifically imagine that the sun could suddenly burst out with several hundred times its ordinary amount of heat and light1 thereby putting us into a proper condition for spectroscopic examination by curious astronomers in distant worlds4 ,but no1 after all1 it is far pleasanter to keep within the strict boundaries of science1 and not imagine anything of the kind4 ,,chapter ,v ,,in ,,summer ,,star-,,lands ,i heard the trailing garments of the night ,sweep through her marble halls1 ,i saw her sable skirts all fringed with light ,from the celestial walls4--,h4 ,w4 ,,longfellow4 ,in the soft air of a summer night1 when fireflies are flashing their lanterns over the fields1 the stars do not sparkle and blaze like those that pierce the frosty skies of winter4 ,the light of ,sirius1 ,aldebaran1 ,rigel1 and other midwinter brilliants possesses a certain gemlike hardness and cutting quality1 but ,antares and ,vega1 the great summer stars1 and ,arcturus1 when he hangs westering in a ,july night1 exhibit a milder radiance1 harmonizing with the character of the season4 ,this difference is1 of course1 atmospheric in origin1 although it may be partly subjective1 depending upon the mental influences of the mutations of ,nature4 ,illustration3 ,,map ,,no4 #ab4 ,the constellation ,scorpio is nearly as striking in outline as ,orion1 and its brightest star1 the red ,antares 7alpha in map ,no4 #ab71 carries concealed in its rays a green jewel which1 to the eye of the enthusiast in telescopic recreation1 appears more beautiful and inviting each time that he penetrates to its hiding place4 ,we shall begin our night's work with this object1 and the four-inch glass will serve our purpose1 although the untrained observer would be more certain of success with the five-inch4 ,a friend of mine has seen the companion of ,antares with a three-inch1 but ,i have never tried the star with so small an aperture4 ,when the air is steady and the companion can be well viewed1 there is no finer sight among the double stars4 ,the contrast of colors is beautifully distinct--fire-red and bright green4 ,the little green star has been seen emerging from behind the moon1 ahead of its ruddy companion4 ,the magnitudes are one and seven and a half or eight1 distance #c1 p4 #bgj4 ,antares is probably a binary1 although its binary character has not yet been established4 ,a slight turn of the telescope tube brings us to the star sigma1 a wide double1 the smaller component of which is blue or plum-colored2 magnitudes four and nine1 distance #bj1 p4 #bgb4 ,from sigma we pass to beta1 a very beautiful object1 of which the three-inch gives us a splendid view4 ,its two components are of magnitudes two and six1 distance #ac1 p4 #cj2 colors1 white and bluish4 ,it is interesting to know that the larger star is itself double1 although none of the telescopes we are using can split it4 ,burnham discovered that it has a tenth-magnitude companion2 distance less than #a1 p4 #hg4 ,and now for a triple1 which will probably require the use of our largest glass4 ,up near the end of the northern prolongation of the constellation we perceive the star xi4 ,the three-inch shows us that it is double2 the five-inch divides the larger star again4 ,the magnitudes are respectively five1 five and a half1 and seven and a half1 distances #j4id1 p4 #bae1 and #g1 p4 #gj4 ,a still more remarkable star1 although one of its components is beyond our reach1 is nu4 ,with the slightest magnifying this object splits up into two stars1 of magnitudes four and seven1 situated rather more than #dj apart4 ,a high power divides the seventh-magnitude companion into two1 each of magnitude six and a half1 distance #a4h1 p4 #db4 ,but 7and this was another of ,burnham's discoveries7 the fourth-magnitude star itself is double1 distance #j4h1 p4 about #j4 ,the companion in this case is of magnitude five and a half4 ,next we shall need a rather low-power eyepiece and our largest aperture in order to examine a star cluster1 ,no4 #dagc1 which was especially admired by ,sir ,william ,herschel1 who discovered that it was not1 as ,messier had supposed1 a circular nebula4 ,herschel regarded it as the richest mass of stars in the firmament1 but with a small telescope it appears merely as a filmy speck that has sometimes been mistaken for a comet4 ,in #ahfj a new star1 between the sixth and seventh magnitude in brilliance1 suddenly appeared directly in or upon the cluster1 and the feeble radiance of the latter was almost extinguished by the superior light of the stranger4 ,the latter disappeared in less than a month1 and has not been seen again1 although it is suspected to be a variable1 and1 as such1 has been designated with the letter ,t4 ,two other known variables1 both very faint1 exist in the immediate neighborhood4 ,according to the opinion that was formerly looked upon with favor1 the variable ,t1 if it is a variable1 simply lies in the line of sight between the earth and the star cluster1 and has no actual connection with the latter4 ,but this opinion may not1 after all1 be correct1 for ,mr4 ,bailey's observations show that variable stars sometimes exist in large numbers in clusters1 although the variables thus observed are of short period4 ,the cluster #dahc1 just west of ,antares1 is also worth a glance with the five-inch glass4 ,it is dense1 but its stars are very small1 so that to enjoy its beauty we should have to employ a large telescope4 ,yet there is a certain attraction in these far-away glimpses of starry swarms1 for they give us some perception of the awful profundity of space4 ,when the mind is rightly attuned for these revelations of the telescope1 there are no words that can express its impressions of the overwhelming perspective of the universe4 ,the southern part of the constellation ,ophiuchus is almost inextricably mingled with ,scorpio4 ,we shall1 therefore1 look next at its attractions1 beginning with the remarkable array of star clusters #dbfd1 #dbfh1 #dbfi1 and #dbgj4 ,all of these are small1 #b' or #c' in diameter1 and globular in shape4 ,no4 #dbfd is the largest1 and we can see some of the stars composing it4 ,but these clusters1 like those just described in ,scorpio1 are more interesting for what they signify than for what they show2 and the interest is not diminished by the fact that their meaning is more or less of a mystery4 ,whether they are composed of pygmy suns or of great solar globes like that one which makes daylight for the earth1 their association in spherical groups is equally suggestive4 ,there are two other star clusters in ,ophiuchus1 and within the limits of map ,no4 #ab1 both of which are more extensive than those we have just been looking at4 ,no4 #dbaa is #e' or #f' in diameter1 also globular1 brighter at the center1 and surrounded by several comparatively conspicuous stars4 ,no4 #dcdf is still larger1 about half as broad as the moon1 and many of its scattered stars are of not less than the ninth magnitude4 ,with a low magnifying power the field of view surrounding the cluster appears powdered with stars4 ,there are only two noteworthy doubles in that part of ,ophiuchus with which we are at present concerned3 #cf1 whose magnitudes are five and seven1 distance #d4c1 p4 #aie1 colors yellow and red2 and #ci1 magnitudes six and seven and a half1 distance #ab1 p4 #cef1 colors yellow or orange and blue4 ,the first named is a binary whose period has not been definitely ascertained4 ,the variable ,r has a period a little less than three hundred and three days4 ,at its brightest it is of magnitude seven or eight1 and at minimum it diminishes to about the twelfth magnitude4 ,the spot where the new star of #afjd appeared is indicated on the map4 ,this was1 with the exception of ,tycho's star in #aegb1 the brightest temporary star of which we possess a trustworthy account4 ,it is frequently referred to as ,kepler's star1 because ,kepler watched it with considerable attention1 but unfortunately he was not as good an observer as ,tycho was4 ,the star was first seen on ,october #aj1 #afjd1 and was then brighter than ,jupiter4 ,it did not1 however1 equal ,venus4 ,it gradually faded and in ,march1 #afjf1 disappeared4 ,about twelve degrees northwest of the place of the star of #afjd1 and in that part of the constellation ,serpens which is included in map ,no4 #ab1 we find the location of another temporary star1 that of #ahdh4 ,it was first noticed by ,mr4 ,hind on ,april #bhth of that year1 when its magnitude was not much above the seventh1 and its color was red4 ,it brightened rapidly1 until on ,may #b;d it was of magnitude three and a half4 ,then it began to fade1 but very slowly1 and it has never entirely disappeared4 ,it is now of the twelfth or thirteenth magnitude4 ,in passing we may glance with a low power at nu ,serpentis1 a wide double1 magnitudes four and nine1 distance #ej1 p4 #ca1 colors contrasted but uncertain4 ,sagittarius and its neighbor1 the small but rich constellation ,scutum ,sobieskii1 attract us next4 ,we shall first deal with the western portions of these constellations which are represented on ,map ,no4 #ab4 ,the star in ,sagittarius is a wide triple1 magnitudes three and a half1 nine and a half1 and ten1 distances #dj1 p4 #cae1 and #de1 p4 #aad4 ,but the chief glory of ,sagittarius 7and the same statement applies to ,scutum ,sobieskii7 lies in its assemblage of star clusters4 ,one of these1 ,no4 #dcfa1 also known as ,m #h1 is plainly visible to the naked eye as a bright spot in the ,milky ,way4 ,we turn our five-inch telescope1 armed with a low magnifying power1 upon this subject and enjoy a rare spectacle4 ,as we allow it to drift through the field we see a group of three comparatively brilliant stars advancing at the front of a wonderful train of mingled star clusters and nebulous clouds4 ,a little northwest of it appears the celebrated trifid nebula1 ,no4 #dcee on the map4 ,there is some evidence that changes have occurred in this nebula since its discovery in the last century4 ,barnard has made a beautiful photograph showing ,m #h and the trifid nebula on the same plate1 and he remarks that the former is a far more remarkable object than its more famous neighbor4 ,near the eastern border of the principal nebulous cloud there is a small and very black hole with a star poised on its eastern edge4 ,this hole and the star are clearly shown in the photograph4 ,cluster ,no4 #dcig 7,m #bd7 is usually described as resembling1 to the naked eye1 a protuberance on the edge of the ,milky ,way4 ,it is nearly three times as broad as the moon1 and is very rich in minute stars1 which are at just such a degree of visibility that crowds of them continually appear and disappear while the eye wanders over the field1 just as faces are seen and lost in a vast assemblage of people4 ,this kind of luminous agitation is not peculiar to ,m #bd1 although that cluster exhibits it better than most others do on account of both the multitude and the minuteness of its stars4 ,a slight sweep eastward brings us to yet another meeting place of stars1 the cluster ,m #be1 situated between the variables ,u and ,v4 ,this is brilliant and easily resolved into its components1 which include a number of double stars4 ,the two neighboring variables just referred to are interesting4 ,u has a period of about six days and three quarters1 and its range of magnitude runs from the seventh down to below the eighth4 ,v is a somewhat mysterious star4 ,chandler removed it from his catalogue of variables because no change had been observed in its light by either himself1 ,sawyer1 or ,yendell4 ,quirling1 the discoverer of its variability1 gave the range as between magnitudes #g4f and #h4h4 ,it must1 therefore1 be exceedingly erratic in its changes1 resembling rather the temporary stars than the true variables4 ,in that part of ,scutum ,sobieskii contained in map ,no4 #ab we find an interesting double1 ,sigma #bcbe1 whose magnitudes are six and nine1 distance #ab4c1 p4 #bfj1 colors white and orange4 ,sigma #bcjf is a triple1 magnitudes seven1 eight1 and nine1 distances #ab1 p4 #bbj1 and #j4h1 p4 #fh4 ,the third star is1 however1 beyond our reach4 ,the colors of the two larger are respectively yellow and violet4 ,the star cluster #ddjj is about one quarter as broad as the moon1 and easily seen with our smallest aperture4 ,illustration3 ,,map ,,no4 #ac4 ,passing near to the region covered by map ,no4 #ac1 we find the remaining portions of the constellations ,sagittarius and ,scutum ,sobieskii4 ,it will be advisable to finish with the latter first4 ,glance at the clusters #ddbf and #ddcg4 ,neither is large1 but both are rich in stars4 ,the nebula #ddda is a fine object of its kind4 ,it brightens toward the center1 and ,herschel thought he had resolved it into stars4 ,the variable ,r is remarkable for its eccentricities4 ,sometimes it attains nearly the fourth magnitude1 although usually at maximum it is below the fifth1 while at minimum it is occasionally of the sixth and at other times of the seventh or eighth magnitude4 ,its period is irregular4 ,turning back to ,sagittarius1 we resume our search for interesting objects there1 and the first that we discover is another star cluster1 for the stars are wonderfully gregarious in this quarter of the heavens4 ,the number our cluster bears on the map is #ddbd1 corresponding with ,m #bb in ,messier's catalogue4 ,it is very bright1 containing many stars of the tenth and eleventh magnitudes1 as well as a swarm of smaller ones4 ,sir ,john ,herschel regarded the larger stars in this cluster as possessing a reddish tint4 ,possibly there was some peculiarity in his eye that gave him this impression1 for he has described a cluster in the constellation ,toucan in the southern hemisphere as containing a globular mass of rose-colored stars inclosed in a spherical shell of white stars4 ,later observers have confirmed his description of the shape and richness of this cluster in ,toucan1 but have been unable to perceive the red hue of the interior stars4 ,the eastern expanse of ,sagittarius is a poor region compared with the western end of the constellation1 where the wide stream of the ,milky ,way like a great river enriches its surroundings4 ,the variables ,t and ,r are of little interest to us1 for they never become bright enough to be seen without the aid of a telescope4 ,in #ed we find1 however1 an interesting double1 which with larger telescopes than any of ours appears as a triple4 ,the two stars that we see are of magnitudes six and seven and a half1 distance #de1 p4 #db1 colors yellow and blue4 ,the third star1 perhaps of thirteenth magnitude1 is distant #cf1 p4 #bde4 ,retaining map ,no4 #ac as our guide1 we examine the western part of the constellation ,capricornus4 ,its leader alpha is a naked-eye double1 the two stars being a little more than #f' apart4 ,their magnitudes are three and four1 and both have a yellowish hue4 ,the western star is alpha#a1 and is the fainter of the two4 ,the other is designated as alpha#b4 ,both are double4 ,the components of alpha#a are of magnitudes four and eight and a half1 distance #dd1 p4 #bbj4 ,with the ,washington twenty-six-inch telescope a third star of magnitude fourteen has been found at a distance of #dj1 p4 #ahb4 ,in alpha#b the magnitudes of the components are three and ten and a half1 distance #g4d1 p4 #aej4 ,the smaller star has a companion of the twelfth or thirteenth magnitude1 distance #a4b1 p4 #bdj4 ,this1 of course1 is hopelessly beyond our reach4 ,yet another star of magnitude nine1 distance #aed1 p4 #aef1 we may see easily4 ,dropping down to beta1 we find it to be a most beautiful and easy double1 possessing finely contrasted colors1 gold and blue4 ,the larger star is of magnitude three1 and the smaller1 the blue one1 of magnitude six1 distance #bje1 p4 #bfg4 ,between them there is a very faint star which larger telescopes than ours divide into two1 each of magnitude eleven and a half2 separated #c1 p4 #cbe4 ,still farther south and nearly in a line drawn from alpha through beta we find a remarkable group of double stars1 sigma1 pi1 rho1 and omicron4 ,the last three form a beautiful little triangle4 ,we begin with sigma1 the faintest of the four4 ,the magnitudes of its components are six and nine1 distance #ed1 p4 #agg4 ,in pi the magnitudes are five and nine1 distance #c4d1 p4 #ade2 in rho1 magnitudes five and eight1 distance #c4h1 p4 #agg 7a third star of magnitude seven and a half is seen at a distance of #d'1 p4 #aej72 in omicron1 magnitudes six and seven1 distance #bb1 p4 #bdj4 ,the star cluster #dfjh is small1 yet1 on a moonless night1 worth a glance with the five-inch4 ,illustration3 ,,map ,,no4 #ad4 ,we now pass northward to the region covered by map ,no4 #ad1 including the remainder of ,ophiuchus and ,serpens4 ,beginning with the head of ,serpens1 in the upper right-hand corner of the map1 we find that beta1 of magnitude three and a half1 has a ninth-magnitude companion1 distance #cj1 p4 #bfe4 ,the larger star is light blue and the smaller one yellowish4 ,the little star nu is double1 magnitudes five and nine1 distance #ej1 p4 #ca1 colors contrasted but uncertain4 ,in delta we find a closer double1 magnitudes three and four1 distance #c4e1 p4 #aij4 ,it is a beautiful object for the three-inch4 ,the leader of the constellation1 alpha1 of magnitude two and a half1 has a faint companion of only the twelfth magnitude1 distance #fj1 p4 #cej4 ,the small star is bluish4 ,the variable ,r has a period about a week short of one year1 and at maximum exceeds the sixth magnitude1 although sinking at minimum to less than the eleventh4 ,its color is ruddy4 ,passing eastward1 we turn again into ,ophiuchus1 and find immediately the very interesting double1 lambda1 whose components are of magnitudes four and six1 distance #a1 p4 #ee4 ,this is a long-period binary1 and notwithstanding the closeness of its stars1 our four-inch should separate them when the seeing is fine4 ,we shall do better1 however1 to try with the five-inch4 ,sigma #baff consists of two stars of magnitudes six and seven and a half1 distance #bg1 p4 #bhj4 ,sigma #bagc is a double of quite a different order4 ,the magnitudes of its components are both six1 the distance in #ahii #j4ih1 p4 #cca4 ,it is evidently a binary in rapid motion1 as the distance changed from about a quarter of a second in #ahha to more than a second in #ahid4 ,the star tau is a fine triple1 magnitudes five1 six1 and nine1 distances #a4h1 p4 #bed1 and #ajj1 p4 #abg4 ,the close pair is a binary system with a long period of revolution1 estimated at about two hundred years4 ,we discover another group of remarkable doubles in #fg1 #gj1 and #gc4 ,in the first-named star the magnitudes are four and eight1 distance #ee1 p4 #add1 colors finely contrasted1 pale yellow and red4 ,much more interesting1 however1 is #gj1 a binary whose components have completed a revolution since their discovery by ,sir ,william ,herschel1 the period being ninety-five years4 ,the magnitudes are four and six1 or1 according to ,hall1 five and six1 distance in #ahid #b4c2 in #aijj1 #a4de1 according to ,maw4 ,hall says the apparent distance when the stars are closest is about #a4g1 and when they are widest #f4g4 ,this star is one of those whose parallax has been calculated with a reasonable degree of accuracy4 ,its distance from us is about #a1bfj1jjj times the distance of the sun1 the average distance apart of the two stars is about #b1hjj1jjj1jjj miles 7equal to the distance of ,neptune from the sun71 and their combined mass is three times that of the sun4 ,hall has seen in the system of #gj ,ophiuchi three stars of the thirteenth magnitude or less1 at distances of about #fj1 #ij1 and #afe respectively4 ,the star #gc is also a close double1 and beyond our reach4 ,its magnitudes are six and seven1 distance #j4g1 p4 #bde4 ,it is1 no doubt1 a binary4 ,three star clusters in ,ophiuchus remain to be examined4 ,the first of these1 ,no4 #dbef1 is partially resolved into stars by the five-inch4 ,no4 #dcae is globular1 and has a striking environment of bystanding stars4 ,it is about one quarter as broad as the full moon1 and our largest aperture reveals the faint coruscation of its crowded components4 ,no4 #ddaj is a coarser and more scattered star swarm--a fine sight6 ,farther toward the east we encounter a part of ,serpens again1 which contains just one object worth glancing at1 the double theta1 whose stars are of magnitudes four and four and a half1 distance #ba1 p4 #ajd4 ,color1 both yellow1 the smaller star having the deeper hue4 ,illustration3 ,,map ,,no4 #ae4 ,let us next1 with the guidance of map ,no4 #ae1 enter the rich star fields of ,hercules1 and of the head and first coils of ,draco4 ,according to ,argelander1 ,hercules contains more stars visible to the naked eye than any other constellation1 and he makes the number of them one hundred and fifty-five1 nearly two thirds of which are only of the sixth magnitude4 ,but ,heis1 who saw more naked-eye stars than ,argelander1 makes ,ursa ,major precisely equal to ,hercules in the number of stars1 his enumeration showing two hundred and twenty-seven in each constellation1 while1 according to him1 ,draco follows very closely after1 with two hundred and twenty stars4 ,yet1 on account of the minuteness of the majority of their stars1 neither of these constellations makes by any means as brilliant a display as does ,orion1 to which ,argelander assigns only one hundred and fifteen naked-eye stars1 and ,heis one hundred and thirty-six4 ,we begin in ,hercules with the star kappa1 a pretty little double of magnitudes five and a half and seven1 distance #ca1 p4 #aj1 colors yellow and red4 ,not far away we find1 in gamma1 a larger star with a fainter companion1 the magnitudes in this case being three and a half and nine1 distance #ch1 p4 #bdb1 colors white and faint blue or lilac4 ,one of the most beautiful of double stars is alpha ,herculis4 ,the magnitudes are three and six1 distance #d4g1 p4 #aah1 colors orange and green1 very distinct4 ,variability has been ascribed to each of the stars in turn4 ,it is not known that they constitute a binary system1 because no certain evidence of motion has been obtained4 ,another very beautiful and easily separated double is delta1 magnitudes three and eight1 distance #ai1 p4 #age1 colors pale green and purple4 ,sweeping northwestward to zeta1 we encounter a celebrated binary1 to separate which at present requires the higher powers of a six-inch glass4 ,the magnitudes are three and six and a half1 distance in #ahii1 #j4f1 p4 #bfd2 in #aijj1 #j4h1 p4 #bci4 ,the period of revolution is thirty-five years1 and two complete revolutions have been observed4 ,the apparent distance changes from #j4f to #a4f4 ,they were at their extreme distance in #ahhd4 ,two pleasing little doubles are ,sigma #baja1 magnitudes six and nine1 distance #d1 p4 #eg1 and ,sigma #bajd1 magnitudes six and eight1 distance #f1 p4 #bj4 ,at the northern end of the constellation is #db1 a double that requires the light-grasping power of our largest glass4 ,its magnitudes are six and twelve1 distance #bj1 p4 #id4 ,in rho we discover another distinctly colored double1 both stars being greenish or bluish1 with a difference of tone4 ,the magnitudes are four and five and a half1 distance #c4g1 p4 #cji4 ,but the double #ie is yet more remarkable for the colors of its stars4 ,their magnitudes are five and five and a half1 distance #f1 p4 #bfb1 colors1 according to ,webb1 light apple-green and cherry-red4 ,but other observers have noted different hues1 one calling them both golden yellow4 ,i think ,webb's description is more nearly correct4 ,sigma #bbae is a very close double1 requiring larger telescopes than those we are working with4 ,its magnitudes are six and a half and eight1 distance #j4g1 p4 #cjj4 ,it is probably a binary4 ,sigma #bbhi is also close1 but our five-inch will separate it3 magnitudes six and seven1 distance #a4b1 p4 #bcj4 ,turning to 1 we have to deal with a triple1 one of whose stars is at present beyond the reach of our instruments4 ,the magnitudes of the two that we see are four and ten1 distance #ca1 p4 #bdc4 ,the tenth-magnitude star is a binary of short period 7probably less than fifty years71 the distance of whose components was #b in #ahei1 #a in #ahhj1 #j4cd in #ahhi1 and #j4ed in #ahia1 when the position angle was #be1 and rapidly increasing4 ,the distance is still much less than #a4 ,for a glance at a planetary nebula we may turn with the five-inch to ,no4 #dbcd4 ,it is very small and faint1 only #h in diameter1 and equal in brightness to an eighth-magnitude star4 ,only close gazing shows that it is not sharply defined like a star1 and that it possesses a bluish tint4 ,its spectrum is gaseous4 ,the chief attraction of ,hercules we have left for the last1 the famous star cluster between eta and zeta1 ,no4 #dbcj1 more commonly known as ,m #ac4 ,on a still evening in the early summer1 when the moon is absent and the quiet that the earth enjoys seems an influence descending from the brooding stars1 the spectacle of this sun cluster in ,hercules1 viewed with a telescope of not less than five-inches aperture1 captivates the mind of the most uncontemplative observer4 ,with the ,lick telescope ,i have watched it resolve into separate stars to its very center--a scene of marvelous beauty and impressiveness4 ,but smaller instruments reveal only the in-running star streams and the sprinkling of stellar points over the main aggregation1 which cause it to sparkle like a cloud of diamond dust transfused with sunbeams4 ,the appearance of flocking together that those uncountable thousands of stars present calls up at once a picture of our lone sun separated from its nearest stellar neighbor by a distance probably a hundred times as great as the entire diameter of the spherical space within which that multitude is congregated4 ,it is true that unless we assume what would seem an unreasonable remoteness for the ,hercules cluster1 its component stars must be much smaller bodies than the sun2 yet even that fact does not diminish the wonder of their swarming4 ,here the imagination must bear science on its wings1 else science can make no progress whatever4 ,it is an easy step from ,hercules to ,draco4 ,in the conspicuous diamond-shaped figure that serves as a guide-board to the head of the latter1 the southernmost star belongs not to ,draco but to ,hercules4 ,the brightest star in this figure is gamma1 of magnitude two and a half1 with an eleventh-magnitude companion1 distant #abe1 p4 #aaf4 ,two stars of magnitude five compose nu1 their distance apart being #fb1 p4 #cab4 ,a more interesting double is 1 magnitudes five and five1 distance #b4d1 p4 #aeh4 ,both stars are white1 and they present a pretty appearance when the air is steady4 ,they form a binary system of unknown period4 ,sigma #bjgh 7also called #ag ,draconis7 is a triple1 magnitudes six1 six and a half1 and six1 distances #c4h1 p4 #aaf1 and #ij1 p4 #aie4 ,sigma #aihd is an easy double1 magnitudes six and a half and eight and a half1 distance #f4d1 p4 #bgf4 ,the star eta is a very difficult double for even our largest aperture1 on account of the faintness of one of its components4 ,the magnitudes are two and a half and ten1 distance #d4g1 p4 #adj4 ,its near neighbor1 ,sigma #bjed1 may be a binary4 ,its magnitudes are six and seven1 distance #a1 p4 #j4 ,in ,sigma #bcbc we have another triple1 magnitudes five1 eight and a half1 and seven1 distances #c4f1 p4 #cfj1 and #ij1 p4 #bb1 colors white1 blue1 and reddish4 ,a fine double is epsilon1 magnitudes five and eight1 distance #c1 p4 #e4 ,the nebula ,no4 #dcgc is of a planetary character1 and interesting as occupying the pole of the ecliptic4 ,a few years ago ,dr4 ,holden1 with the ,lick telescope1 discovered that it is unique in its form4 ,it consists of a double spiral1 drawn out nearly in the line of sight1 like the thread of a screw whose axis lies approximately endwise with respect to the observer4 ,there is a central star1 and another fainter star is involved in the outer spiral4 ,the form of this object suggests strange ideas as to its origin4 ,but the details mentioned are far beyond the reach of our instruments4 ,we shall only see it as a hazy speck4 ,no4 #ddae is another nebula worth glancing at4 ,it is ,tuttle's so-called variable nebula4 ,illustration3 ,,map ,,no4 #af4 ,there are three constellations represented on map ,no4 #af to which we shall pay brief visits4 ,first ,aquila demands attention4 ,its doubles may be summarized as follows3 #aa1 magnitudes five and nine1 distance #ag4d1 p4 #beb2 pi1 magnitudes six and seven1 distance #a4f1 p4 #abb2 #bc1 magnitudes six and ten1 distance #c4d1 p4 #ab--requires the five-inch and good seeing2 #eg1 magnitudes five and six1 distance #cf1 p4 #agj2 ,sigma #bfed1 magnitudes six and eight1 distance #ab1 p4 #bcd2 ,sigma #bfdd1 magnitudes six and seven1 distance #c4f1 p4 #bjh4 ,the star eta is an interesting variable between magnitudes three and a half and #d4g2 period1 seven days1 four hours1 fourteen minutes4 ,the small red variable ,r changes from magnitude six to magnitude seven and a half and back again in a period of three hundred and fifty-one days4 ,star cluster ,no4 #dddj is a striking object1 its stars ranging from the ninth down to the twelfth magnitude4 ,just north of ,aquila is the little constellation ,sagitta1 containing several interesting doubles and many fine star fields1 which may be discovered by sweeping over it with a low-power eyepiece4 ,the star zeta is double1 magnitudes five and nine1 distance #h4f1 p4 #cab4 ,the larger star is itself double1 but far too close to be split1 except with very large telescopes4 ,in theta we find three components of magnitudes seven1 nine1 and eight respectively1 distances #aa4d1 p4 #cbg1 and #gj1 p4 #bbg4 ,a wide double is epsilon1 magnitudes six and eight1 distance #ib1 p4 #ha4 ,nebula ,no4 #degb is planetary4 ,turning to ,delphinus1 we find a very beautiful double in gamma1 magnitudes four and five1 distance #aa1 p4 #bgc1 colors golden and emerald4 ,the leader alpha1 which is not as bright as its neighbor beta1 and which is believed to be irregularly variable1 is of magnitude four1 and has a companion of nine and a half magnitude at the distance #ce1 p4 #bgh4 ,at a similar distance1 #ce1 p4 #cce1 beta has an eleventh-magnitude companion1 and the main star is also double1 but excessively close1 and much beyond our reach4 ,it is believed to be a swiftly moving binary1 whose stars are never separated widely enough to be distinguished with common telescopes4 ,,chapter ,,vi ,,from ,,lyra ,,to ,,eridanus ,this ,orpheus struck when with his wondrous song ,he charmed the woods and drew the rocks along4--,,manilius4 ,illustration3 ,,map ,,no4 #ag4 ,we resume our celestial explorations with the little constellation ,lyra1 whose chief star1 ,vega 7alpha71 has a very good claim to be regarded as the most beautiful in the sky4 ,the position of this remarkable star is indicated in map ,no4 #ag4 ,every eye not insensitive to delicate shades of color perceives at once that ,vega is not white1 but blue-white4 ,when the telescope is turned upon the star the color brightens splendidly4 ,indeed1 some glasses decidedly exaggerate the blueness of ,vega1 but the effect is so beautiful that one can easily forgive the optical imperfection which produces it4 ,with our four-inch we look for the well-known companion of ,vega1 a tenth-magnitude star1 also of a blue color deeper than the hue of its great neighbor4 ,the distance is #ej1 p4 #aeh4 ,under the most favorable circumstances it might be glimpsed with the three-inch1 but1 upon the whole1 ,i should regard it as too severe a test for so small an aperture4 ,vega is one of those stars which evidently are not only enormously larger than the sun 7one estimate makes the ratio in this case nine hundred to one71 but whose physical condition1 as far as the spectroscope reveals it1 is very different from that of our ruling orb4 ,like ,sirius1 ,vega displays the lines of hydrogen most conspicuously1 and it is probably a much hotter as well as a much more voluminous body than the sun4 ,close by1 toward the east1 two fourth-magnitude stars form a little triangle with ,vega4 ,both are interesting objects for the telescope1 and the northern one1 epsilon1 has few rivals in this respect4 ,let us first look at it with an opera glass4 ,the slight magnifying power of such an instrument divides the star into two twinkling points4 ,they are about two and a quarter minutes of arc apart1 and exceptionally sharp-sighted persons are able to see them divided with the naked eye4 ,now take the three-inch telescope and look at them1 with a moderate power4 ,each of the two stars revealed by the opera glass appears double1 and a fifth star of the ninth magnitude is seen on one side of an imaginary line joining the two pairs4 ,the northern-most pair is named epsilon#a1 the magnitudes being fifth and sixth1 distance #c1 p4 #ae4 ,the other pair is epsilon#b1 magnitudes fifth and sixth1 distance #b4c1 p4 #acc4 ,each pair is apparently a binary2 but the period of revolution is unknown4 ,some have guessed a thousand years for one pair1 and two thousand for the other4 ,another guess gives epsilon#a a period of one thousand years1 and epsilon#b a period of eight hundred years4 ,hall1 in his double-star observations1 simply says of each1 ,a slow motion4 ,purely by guesswork a period has also been assigned to the two pairs in a supposed revolution around their common center1 the time named being about a million years4 ,it is not known1 however1 that such a motion exists4 ,manifestly it could not be ascertained within the brief period during which scientific observations of these stars have been made4 ,the importance of the element of time in the study of stellar motions is frequently overlooked1 though not1 of course1 by those who are engaged in such work4 ,the sun1 for instance1 and many of the stars are known to be moving in what appear to be straight lines in space1 but observations extending over thousands of years would probably show that these motions are in curved paths1 and perhaps in closed orbits4 ,if now in turn we take our four-inch glass1 we shall see something else in this strange family group of epsilon ,lyr4 ,between epsilon#a and epsilon#b1 and placed one on each side of the joining line1 appear two exceedingly faint specks of light1 which ,sir ,john ,herschel made famous under the name of the debillissima4 ,they are of the twelfth or thirteenth magnitude1 and possibly variable to a slight degree4 ,if you can not see them at first1 turn your eye toward one side of the field of view1 and thus1 by bringing their images upon a more sensitive part of the retina1 you may glimpse them4 ,the sight is not much1 yet it will repay you1 as every glance into the depths of the universe does4 ,the other fourth-magnitude star near ,vega is zeta1 a wide double1 magnitudes fourth and sixth1 distance #dd1 p4 #aej4 ,below we find beta1 another very interesting star1 since it is both a multiple and an eccentric variable4 ,it has four companions1 three of which we can easily see with our three-inch2 the fourth calls for the five-inch2 the magnitudes are respectively four1 seven or under1 eight1 eight and a half1 and eleven2 distances #de1 p4 #aej2 #fe1 p4 #cbj2 #he1 p4 #bj2 and #df1 p4 #bdh4 ,the primary1 beta1 varies from about magnitude three and a half to magnitude four and a half1 the period being twelve days1 twenty-one hours1 forty-six minutes1 and fifty-eight seconds4 ,two unequal maxima and minima occur within this period4 ,in the spectrum of this star some of the hydrogen lines and the ,d#c line 7the latter representing helium1 a constituent of the sun and of some of the stars1 which1 until its recent discovery in a few rare minerals was not known to exist on the earth7 are bright1 but they vary in visibility4 ,moreover1 dark lines due to hydrogen also appear in its spectrum simultaneously with the bright lines of that element4 ,then1 too1 the bright lines are sometimes seen double4 ,professor ,pickering's explanation is that beta ,lyr probably consists of two stars1 which1 like the two composing beta ,aurig1 are too close to be separated with any telescope now existing1 and that the body which gives the bright lines is revolving in a circle in a period of about twelve days and twenty-two hours around the body which gives the dark lines4 ,he has also suggested that the appearances could be accounted for by supposing a body like our sun to be rotating in twelve days and twenty-two hours1 and having attached to it an enormous protuberance extending over more than one hundred and eighty degrees of longitude1 so that when one end of it was approaching us with the rotation of the star the other end would be receding1 and a splitting of the spectral lines at certain periods would be the consequence4 ,the variation in light1 he adds1 may be caused by the visibility of a larger or smaller portion of this protuberance4 ,unfortunate star1 doomed to carry its parasitical burden of hydrogen and helium1 like ,sindbad in the clasp of the ,old ,man of the ,sea6 ,surely1 the human imagination is never so wonderful as when it bears an astronomer on its wings4 ,yet it must be admitted that the facts in this case are well calculated to summon the genius of hypothesis4 ,and the puzzle is hardly simplified by ,blopolsky's observation that the body in beta ,lyr giving dark hydrogen lines shows those lines also split at certain times4 ,it has been calculated1 from a study of the phenomena noted above1 that the bright-line star in beta ,lyr is situated at a distance of about fifteen million miles from the center of gravity of the curiously complicated system of which it forms a part4 ,we have not yet exhausted the wonders of ,lyra4 ,on a line from beta to gamma1 and about one third of the distance from the former to the latter1 is the celebrated ,ring ,nebula1 indicated on the map by the number #dddg4 ,we need all the light we can get to see this object well1 and so1 although the three-inch will show it1 we shall use the five-inch4 ,beginning with a power of one hundred diameters1 which exhibits it as a minute elliptical ring1 rather misty1 very soft and delicate1 and yet distinct1 we increase the magnification first to two hundred and finally to three hundred1 in order to distinguish a little better some of the details of its shape4 ,upon the whole1 however1 we find that the lowest power that clearly brings out the ring gives the most satisfactory view4 ,the circumference of the ring is greater than that of the planet ,jupiter4 ,its ellipticity is conspicuous1 the length of the longer axis being #gh and that of the shorter #fj4 ,closely following the nebula as it moves through the field of view1 our five-inch telescope reveals a faint star of the eleventh or twelfth magnitude1 which is suspected of variability4 ,the largest instruments1 like the ,washington and the ,lick glasses1 have shown perhaps a dozen other stars apparently connected with the nebula4 ,a beautiful sparkling effect which the nebula presents was once thought to be an indication that it was really composed of a circle of stars1 but the spectroscope shows that its constitution is gaseous4 ,just in the middle of the open ring is a feeble star1 a mere spark in the most powerful telescope4 ,but when the ,ring ,nebula is photographed--and this is seen beautifully in the photographs made with the ,crossley reflector on ,mount ,hamilton by the late ,prof4 ,j4 ,e4 ,keeler--this excessively faint star imprints its image boldly as a large bright blur1 encircled by the nebulous ring1 which itself appears to consist of a series of intertwisted spirals4 ,not far away we find a difficult double star1 #ag1 whose components are of magnitudes six and ten or eleven1 distance #c4g1 p4 #cbe4 ,from ,lyra we pass to ,cygnus1 which1 lying in one of the richest parts of the ,milky ,way1 is a very interesting constellation for the possessor of a telescope4 ,its general outlines are plainly marked for the naked eye by the figure of a cross more than twenty degrees in length lying along the axis of the ,milky ,way4 ,the foot of the cross is indicated by the star beta1 also known as ,albireo1 one of the most charming of all the double stars4 ,the three-inch amply suffices to reveal the beauty of this object1 whose components present as sharp a contrast of light yellow and deep blue as it would be possible to produce artificially with the purest pigments4 ,the magnitudes are three and seven1 distance #cd4f1 p4 #ee4 ,no motion has been detected indicating that these stars are connected in orbital revolution1 yet no one can look at them without feeling that they are intimately related to one another4 ,it is a sight to which one returns again and again1 always with undiminished pleasure4 ,the most inexperienced observer admires its beauty1 and after an hour spent with doubtful results in trying to interest a tyro in double stars it is always with a sense of assured success that one turns the telescope to beta ,cygni4 ,following up the beam of the imaginary cross along the current of the ,milky ,way1 every square degree of which is here worth long gazing into1 we come to a pair of stars which contend for the name-letter chi4 ,on our map the letter is attached to the southernmost of the two1 a variable of long period--four hundred and six days--whose changes of brilliance lie between magnitudes four and thirteen1 but which exhibits much irregularity in its maxima4 ,the other star1 not named but easily recognized in the map1 is sometimes called #ag4 ,it is an attractive double whose colors faintly reproduce those of beta4 ,the magnitudes are five and eight1 distance #bf1 p4 #gc4 ,where the two arms of the cross meet is gamma1 whose remarkable cortge of small stars running in curved streams should not be missed4 ,use the lowest magnifying power4 ,at the extremity of the western arm of the cross is delta1 a close double1 difficult for telescopes of moderate aperture on account of the difference in the magnitudes of the components4 ,we may succeed in dividing it with the five-inch4 ,the magnitudes are three and eight1 distance #a4e1 p4 #caj4 ,it is regarded as a binary of long and as yet unascertained period4 ,in omicron#b we find a star of magnitude four and orange in color1 having two blue companions1 the first of magnitude seven and a half1 distance #ajg1 p4 #agd1 and the second of magnitude five and a half1 distance #ceh1 p4 #cbd4 ,farther north is psi1 which presents to us the combination of a white five-and-a-half-magnitude star with a lilac star of magnitude seven and a half4 ,the distance is #c1 p4 #ahd4 ,a very pretty sight4 ,we now pass to the extremity of the other arm of the cross1 near which lies the beautiful little double #di1 whose components are of magnitudes six and eight1 distance #b4h1 p4 #ej4 ,the colors are yellow and blue1 conspicuous and finely contrasted4 ,a neighboring double of similar hues is #eb1 in which the magnitudes are four and nine1 distance #f1 p4 #fj4 ,sweeping a little way northward we come upon an interesting binary1 lambda1 which is unfortunately beyond the dividing power of our largest glass4 ,a good seven-inch or seven-and-a-half-inch should split it under favorable circumstances4 ,its magnitudes are six and seven1 distance #j4ff1 p4 #gd4 ,the next step carries us to a very famous object1 #fa ,cygni1 long known as the nearest star in the northern hemisphere of the heavens4 ,it is a double which our three-inch will readily divide1 the magnitudes being both six1 distance #ba1 p4 #abb4 ,the distance of #fa ,cygni1 according to ,hall's parallax of #j4bg1 is about #gj1jjj1jjj1jjj1jjj miles4 ,there is some question whether or not it is a binary1 for1 while the twin stars are both moving in the same direction in space with comparative rapidity1 yet conclusive evidence of orbital motion is lacking4 ,when one has noticed the contrast in apparent size between this comparatively near-by star1 which the naked eye only detects with considerable difficulty1 and some of its brilliant neighbors whose distance is so great as to be immeasurable with our present means1 no better proof will be needed of the fact that the faintness of a star is not necessarily an indication of remoteness4 ,we may prepare our eyes for a beautiful exhibition of contrasted colors once more in the star 4 ,this is really a quadruple1 although only two of its components are close and conspicuous4 ,the magnitudes are five1 six1 seven and a half1 and twelve2 distances #b4d1 p4 #aba2 #bjh1 p4 #ef2 and #ce1 p4 #bfd4 ,the color of the largest star is white and that of its nearest companion blue2 the star of magnitude seven and a half is also blue4 ,the star cluster #dfha is a fine sight with our largest glass4 ,in the map we find the place marked where the new star of #ahgf made its appearance4 ,this was first noticed on ,november #bd1 #ahgf1 when it shone with the brilliance of a star of magnitude three and a half4 ,its spectrum was carefully studied1 especially by ,vogel1 and the very interesting changes that it underwent were noted4 ,within a year the star had faded to less than the tenth magnitude1 and its spectrum had completely changed in appearance1 and had come to bear a close resemblance to that of a planetary nebula4 ,this has been quoted as a possible instance of a celestial collision through whose effects the solid colliding masses were vaporized and expanded into a nebula4 ,at present the star is very faint and can only be seen with the most powerful telescopes4 ,compare with the case of ,nova ,aurig1 previously discussed4 ,underneath ,cygnus we notice the small constellation ,vulpecula4 ,it contains a few objects worthy of attention1 the first being the nebula #decb1 the dumb-bell nebula of ,lord ,rosse4 ,with the four-inch1 and better with the five-inch1 we are able to perceive that it consists of two close-lying tufts of misty light4 ,many stars surround it1 and large telescopes show them scattered between the two main masses of the nebula4 ,the ,lick photographs show that its structure is spiral4 ,the star #aa points out the place where a new star of the third magnitude appeared in #afgj4 ,sigma #bfie is a close double1 magnitudes six and eight1 distance #j4if1 p4 #gh4 ,illustration3 ,,map ,,no4 #ah4 ,we turn to map ,no4 #ah1 and1 beginning at the western end of the constellation ,aquarius1 we find the variable ,t1 which ranges between magnitudes seven and thirteen in a period of about two hundred and three days4 ,its near neighbor ,sigma #bgbi is a very close double1 beyond the separating power of our five-inch1 the magnitudes being six and seven1 distance #j4f1 p4 #agf4 ,sigma #bgde1 also known as #ab ,aquarii1 is a good double for the three-inch4 ,its magnitudes are six and eight1 distance #b4h1 p4 #aij4 ,in zeta we discover a beauty4 ,it is a slow binary of magnitudes four and four1 distance #c4a1 p4 #cba4 ,according to some observers both stars have a greenish tinge4 ,the star #da is a wider double1 magnitudes six and eight1 distance #e1 p4 #aae1 colors yellow and blue4 ,the uncommon stellar contrast of white with light garnet is exhibited by tau1 magnitudes six and nine1 distance #bg1 p4 #aae4 ,yellow and blue occur again conspicuously in psi1 magnitudes four and a half and eight and a half1 distance #ej1 p4 #caj4 ,rose and emerald have been recorded as the colors exhibited in ,sigma #biih1 whose magnitudes are five and seven1 distance #a4c1 p4 #cdf4 ,the variables ,s and ,r are both red4 ,the former ranges between magnitudes eight and twelve1 period two hundred and eighty days1 and the latter between magnitudes six and eleven1 period about three hundred and ninety days4 ,the nebula #dfbh is ,rosse's ,saturn nebula1 so called because with his great telescope it presented the appearance of a nebulous model of the planet ,saturn4 ,with our five-inch we see it simply as a planetary nebula4 ,we may also glance at another nebula1 #dfgh1 which appears circular and is pinned with a little star at the edge4 ,the small constellation ,equuleus contains a surprisingly large number of interesting objects4 ,sigma #bgce is a rather close double1 magnitudes six and eight1 distance #a4h1 p4 #bhg4 ,sigma #bgcg 7the first star to the left of ,sigma #bgce1 the name having accidentally been omitted from the map7 is a beautiful triple1 although the two closest stars1 of magnitudes six and seven1 can not be separated by our instruments4 ,their distance in #ahhf was #j4gh1 p4 #bhf1 and they had then been closing rapidly since #ahhd1 when the distance was #a4bf4 ,the third star1 of magnitude eight1 is distant #aa1 p4 #ge4 ,sigma #bgdd consists of two stars1 magnitudes six and seven1 distance #a4d1 p4 #a4fg4 ,it is probably a binary4 ,sigma #bgdb is wider double1 magnitudes both six1 distance #b4f1 p4 #bbe4 ,another triple1 one of whose components is beyond our reach1 is gamma4 ,here the magnitudes are fifth1 twelfth1 and sixth1 distances #b1 p4 #bgd and #cff4 ,it would also be useless for us to try to separate delta1 but it is interesting to remember that this is one of the closest of known double stars1 the magnitudes being fourth and fifth1 distance #j4d1 p4 #aih4 ,these data are from ,hall's measurements in #ahhg4 ,the star is1 no doubt1 a binary4 ,with the five-inch we may detect one and perhaps two of the companion stars in the quadruple beta4 ,the magnitudes are five1 ten1 and two eleven1 distances #fg1 p4 #cji2 #hf1 p4 #bgf2 and #f4e1 p4 #ae4 ,the close pair is comprised in the tenth-magnitude star4 ,illustration3 ,,map ,,no4 #ai4 ,map ,no4 #ai introduces us to the constellation ,pegasus1 which is comparatively barren to the naked eye1 and by no means rich in telescopic phenomena4 ,the star epsilon1 of magnitude two and a half1 has a blue companion of the eighth magnitude1 distance #ach1 p4 #cbd2 colors yellow and violet4 ,a curious experiment that may be tried with this star is described by ,webb1 who ascribes the discovery of the phenomenon to ,sir ,john ,herschel4 ,when near the meridian the small star in epsilon appears1 in the telescope1 underneath the large one4 ,if now the tube of the telescope be slightly swung from side to side the small star will appear to describe a pendulumlike movement with respect to the large one4 ,the explanation suggested is that the comparative faintness of the small star causes its light to affect the retina of the eye less quickly than does that of its brighter companion1 and1 in consequence1 the reversal of its apparent motion with the swinging of the telescope is not perceived so soon4 ,the third-magnitude star eta has a companion of magnitude ten and a half1 distance #ij1 p4 #cdj4 ,the star beta1 of the second magnitude1 and reddish1 is variable to the extent of half a magnitude in an irregular period1 and gamma1 of magnitude two and a half1 has an eleventh-magnitude companion1 distance #afb1 p4 #bhe4 ,illustration3 ,,map ,,no4 #bj4 ,our interest is revived on turning1 with the guidance of map ,no4 #bj1 from the comparative poverty of ,pegasus to the spacious constellation ,cetus4 ,the first double star that we meet in this constellation is #bf1 whose components are of magnitudes six and nine1 distance #af4d1 p4 #beb2 colors1 topaz and lilac4 ,not far away is the closer double #db1 composed of a sixth and a seventh magnitude star1 distance #a4be1 p4 #cej4 ,the four-inch is capable of splitting this star1 but we shall do better to use the five-inch4 ,in passing we may glance at the tenth-magnitude companion to eta1 distance #bbe1 p4 #cjd4 ,another wide pair is found in zeta1 magnitudes three and nine1 distance #ahe1 p4 #dj4 ,the next step brings us to the wonderful variable omicron1 or ,mira1 whose changes have been watched for three centuries1 the first observer of the variability of the star having been ,david ,fabricius in #aeif4 ,not only is the range of variability very great1 but the period is remarkably irregular4 ,in the time of ,hevelius1 ,mira was once invisible for four years4 ,when brightest1 the star is of about the second magnitude1 and when faintest1 of the ninth magnitude1 but at maximum it seldom exhibits the greatest brilliance that it has on a few occasions shown itself capable of attaining4 ,ordinarily it begins to fade after reaching the fourth or fifth magnitude4 ,the period averages about three hundred and thirty-one days1 but is irregularly variable to the extent of twenty-five days4 ,its color is red1 and its spectrum shows bright lines1 which it is believed disappear when the star sinks to a minimum4 ,among the various theories proposed to account for such changes as these the most probable appears to be that which ascribes them to some cause analogous to that operating in the production of sun spots4 ,the outburst of light1 however1 as pointed out by ,scheiner1 should be regarded as corresponding to the maximum and not the minimum stage of sun-spot activity4 ,according to this view1 the star is to be regarded as possessing an extensive atmosphere of hydrogen1 which1 during the maximum1 is upheaved into enormous prominences1 and the brilliance of the light from these prominences suffices to swamp the photospheric light1 so that in the spectrum the hydrogen lines appear bright instead of dark4 ,it is not possible to suppose that ,mira can be the center of a system of habitable planets1 no matter what we may think of the more constant stars in that regard1 because its radiation manifestly increases more than six hundred fold1 and then falls off again to an equal extent once in every ten or eleven months4 ,i have met people who can not believe that the ,almighty would make a sun and then allow its energies to go to waste1 by not supplying it with a family of worlds4 ,but ,i imagine that if they had to live within the precincts of ,mira ,ceti they would cry out for exemption from their own law of stellar utility4 ,the most beautiful double star in ,cetus is gamma1 magnitudes three and seven1 distance #c1 p4 #bhh2 hues1 straw-color and blue4 ,the leading star alpha1 of magnitude two and a half1 has a distant blue companion three magnitudes fainter1 and between them are two minute stars1 the southernmost of which is a double1 magnitudes both eleven1 distance #aj1 p4 #bbe4 ,the variable ,s ranges between magnitudes seven and twelve in a somewhat irregular period of about eleven months1 while ,r ranges between the seventh and the thirteenth magnitudes in a period of one hundred and sixty-seven days4 ,illustration3 ,,map ,,no4 #ba4 ,the constellation ,eridanus1 represented in map ,no4 #ba1 contains a few fine double stars1 one of the most interesting of which is #ab1 a rather close binary4 ,the magnitudes are four and eight1 distance #b1 p4 #cbg4 ,we shall take the five-inch for this1 and a steady atmosphere and sharp seeing will be necessary on account of the wide difference in the brightness of the component stars4 ,amateurs frequently fail to make due allowance for the effect of such difference4 ,when the limit of separating power for a telescope of a particular aperture is set at #a or #b1 as the case may be1 it is assumed that the stars composing the doubles on which the test is made shall be of nearly the same magnitude1 or at least that they shall not differ by more than one or two magnitudes at the most4 ,the stray light surrounding a comparatively bright star tends to conceal a faint companion1 although the telescope may perfectly separate them so far as the stellar disks are concerned4 ,then1 too1 ,i have observed in my own experience that a very faint and close double is more difficult than a brighter pair not more widely separated1 usually on account of the defect of light1 and this is true even when the components of the faint double are of equal magnitude4 ,sigma #dgj1 otherwise known as #cb ,eridani1 is a superb object on account of the colors of its components1 the larger star being a rich topaz and the smaller an ultramarine2 while the difference in magnitude is not as great as in many of the colored doubles4 ,the magnitudes are five and seven1 distance #f4g1 p4 #cdh4 ,the star gamma1 of magnitude two and a half1 has a tenth-magnitude companion1 distant #ea1 p4 #bch4 ,sigma #eaf1 also called #ci ,eridani1 consists of two stars of magnitudes six and nine1 distance #f4d1 p4 #aej2 colors1 yellow and blue4 ,the supposed binary character of this star has not yet been established4 ,in omicron#b we come upon an interesting triple star1 two of whose components at any rate we can easily see4 ,the largest component is of the fourth magnitude4 ,at a distance of #hb1 p4 #aje1 we find a tenth-magnitude companion4 ,this companion is itself double1 the magnitudes of its components being ten and eleven1 distance #b4f1 p4 #ih4 ,hall says of these stars that they form a remarkable system4 ,he has also observed a fourth star of the twelfth magnitude1 distant #de from the largest star1 p4 #he4 ,this is apparently unconnected with the others1 although it is only half as distant as the tenth-magnitude component is from the primary4 ,sigma #eij is interesting because of the similarity of its two components in size1 both being of about the seventh magnitude1 distance #aj1 p4 #cah4 ,finally1 we turn to the nebula #hbf4 ,this is planetary in form and inconspicuous1 but ,lassell has described it as presenting a most extraordinary appearance with his great reflector--a circular nebula lying upon another fainter and larger nebula of a similar shape1 and having a star in its center4 ,yet it may possibly be an immensely distant star cluster instead of a nebula1 since its spectrum does not appear to be gaseous4 ,,chapter ,,vii ,,pisces1 ,,aries1 ,,taurus1 ,,and ,,the ,,northern ,,stars ,now sing we stormy skies when ,autumn weighs ,the year1 and adds to nights and shortens days1 ,and suns declining shine with feeble rays4--,,dryden',s ,,virgil4 ,illustration3 ,,map ,,no4 #bb4 ,the eastern end of ,pisces1 represented in map ,no4 #bb1 includes most of the interesting telescopic objects that the constellation contains4 ,we begin our exploration at the star numbered #ee1 a double that is very beautiful when viewed with the three-inch glass4 ,the components are of magnitudes five and eight1 distance #f4f1 p4 #aib4 ,the larger star is yellow and the smaller deep blue4 ,the star #fe1 while lacking the peculiar charm of contrasted colors so finely displayed in #ee1 possesses an attraction in the equality of its components which are both of the sixth magnitude and milk-white4 ,the distance is #d4e1 p4 #aah4 ,in #ff we find a swift binary whose components are at present far too close for any except the largest telescopes4 ,the distance in #ahid was only #j4cf1 p4 #cbi4 ,the magnitudes are six and seven4 ,in contrast with this excessively close double is psi1 whose components are both of magnitude five and a half1 distance #cj1 p4 #afj4 ,dropping down to #gg we come upon another very wide and pleasing double1 magnitudes six and seven1 distance #cc1 p4 #hb1 colors white and lilac or pale blue4 ,hardly less beautiful is zeta magnitudes five and six1 distance #bd1 p4 #fd4 ,finest of all is alpha1 which exhibits a remarkable color contrast1 the larger star being greenish and the smaller blue4 ,the magnitudes are four and five1 distance #c1 p4 #cbj4 ,this star is a binary1 but the motion is slow4 ,the variable ,r ranges between magnitudes seven and thirteen1 period three hundred and forty-four days4 ,the constellation ,aries contains several beautiful doubles1 all but one of which are easy for our smallest aperture4 ,the most striking of these is gamma1 which is historically interesting as the first double star discovered4 ,the discovery was made by ,robert ,hooke in #affd by accident1 while he was following the comet of that year with his telescope4 ,he expressed great surprise on noticing that the glass divided the star1 and remarked that he had not met with a like instance in all the heavens4 ,his observations could not have been very extensive or very carefully conducted1 for there are many double stars much wider than gamma ,arietis which ,hooke could certainly have separated if he had examined them4 ,the magnitudes of the components of gamma are four and four and a half1 or1 according to ,hall1 both four2 distance #h4e1 p4 #ahj4 ,a few degrees above gamma1 passing by beta1 is a wide double lambda1 magnitudes five and eight1 distance #cg1 p4 #de1 colors white and lilac or violet4 ,three stars are to be seen in #ad3 magnitudes five and a half1 ten1 and nine1 distances #hc1 p4 #cf1 and #ajf1 p4 #bgh1 colors white1 blue1 and lilac4 ,the star #cj is a very pretty double1 magnitudes six and seven1 distance #ch4f1 p4 #bgc4 ,sigma #bhi consists of a topaz star combined with a sapphire1 magnitudes six and nine1 distance #bh4e1 p4 #j4 ,the fourth-magnitude star #da has several faint companions4 ,the magnitudes of two of these are eleven and nine1 distances #cd1 p4 #bjc1 and #acj1 p4 #bcj4 ,we discover another triple in pi1 magnitudes five1 eight1 and eleven1 distances #c4bd1 p4 #abb1 and #be1 p4 #aaj4 ,the double mentioned above as being too close for our three-inch glass is epsilon1 which1 however1 can be divided with the four-inch1 although the five-inch will serve us better4 ,the magnitudes are five and a half and six1 distance #a4bf1 p4 #bjb4 ,the star #eb has two companions1 one of which is so close that our instruments can not separate it1 while the other is too faint to be visible in the light of its brilliant neighbor without the aid of a very powerful telescope4 ,illustration3 ,,map ,,no4 #bc4 ,we are now about to enter one of the most magnificent regions in the sky1 which is hardly less attractive to the naked eye than ,orion1 and which men must have admired from the beginning of their history on the earth1 the constellation ,taurus 7map ,no4 #bc74 ,two groups of stars especially distinguish ,taurus1 the ,hyades and the ,pleiades1 and both are exceedingly interesting when viewed with the lowest magnifying powers of our telescopes4 ,we shall begin with a little star just west of the ,pleiades1 ,sigma #dab1 also called #g ,tauri4 ,this is a triple1 but we can see it only as a double1 the third star being exceedingly close to the primary4 ,the magnitudes are six and a half1 seven1 and ten1 distances #j4c1 p4 #baf1 and #bb1 p4 #fb4 ,in the ,pleiades we naturally turn to the brightest star eta1 or ,alcyone1 famous for having once been regarded as the central sun around which our sun and a multitude of other luminaries were supposed to revolve1 and picturesque on account of the little triangle of small stars near it which the least telescopic assistance enables us to see4 ,one may derive much pleasure from a study of the various groupings of stars in the ,pleiades4 ,photography has demonstrated1 what had long been suspected from occasional glimpses revealed by the telescope1 that this celebrated cluster of stars is intermingled with curious forms of nebul4 ,the nebulous matter appears in festoons1 apparently attached to some of the larger stars1 such as ,alcyone1 ,merope1 and ,maia1 and in long1 narrow1 straight lines1 the most remarkable of which1 a faintly luminous thread starting midway between ,maia and ,alcyone and running eastward some #dj'1 is beaded with seven or eight stars4 ,the width of this strange nebulous streak is1 on an average1 #c or #d1 and there is1 perhaps1 no more wonderful phenomenon anywhere in celestial space4 ,unfortunately1 no telescope is able to show it1 and all our knowledge about it is based upon photographs4 ,it might be supposed that it was a nebulous disk seen edgewise1 but for the fact that at the largest star involved in its course it bends sharply about #aj out of its former direction1 and for the additional fact that it seems to take its origin from a curved offshoot of the intricate nebulous mass surrounding ,maia4 ,exactly at the point where this curve is transformed into a straight line shines a small star6 ,in view of all the facts the idea does not seem to be very far-fetched that in the ,pleiades we behold an assemblage of suns1 large and small1 formed by the gradual condensation of a nebula1 and in which evolution has gone on far beyond the stage represented by the ,orion nebula1 where also a group of stars may be in process of formation out of nebulous matter4 ,if we look a little farther along this line of development1 we may perceive in such a stellar assemblage as the cluster in ,hercules1 a still later phase wherein all the originally scattered material has1 perhaps1 been absorbed into the starry nuclei4 ,illustration3 ,,the ,,chief ,,stars ,,in ,,the ,,pleiades4 ,the yellow star ,sigma #dcj has two companions3 magnitudes six1 nine1 and nine and a half1 distances #bf1 p4 #ee1 and #ci1 p4 #cjb4 ,the star #cj of the fifth magnitude has a companion of the ninth magnitude1 distance #i1 p4 #eh1 colors emerald and purple1 faint4 ,an interesting variable1 of the type of ,algol1 is lambda1 which at maximum is of magnitude three and four tenths and at minimum of magnitude four and two tenths4 ,its period from one maximum to the next is about three days and twenty-three hours1 but the actual changes occupy only about ten hours1 and it loses light more swiftly than it regains it4 ,a combination of red and blue is presented by ,phi 7mistakenly marked on map ,no4 #bc as psi74 ,the magnitudes are six and eight1 distance #ef1 p4 #bdb4 ,a double of similar magnitudes is chi1 distance #ai1 p4 #be4 ,between the two stars which the naked eye sees in kappa is a minute pair1 each of less than the eleventh magnitude1 distance #e1 p4 #cbd4 ,another naked-eye double is formed by theta#a and theta#b1 in the ,hyades4 ,the magnitudes are five and five and a half1 distance about #e' #cg4 ,the leading star of ,taurus1 ,aldebaran 7alpha71 is celebrated for its reddish color4 ,the precise hue is rather uncertain1 but ,aldebaran is not orange as ,betelgeuse in ,orion is1 and no correct eye can for an instant confuse the colors of these two stars1 although many persons seem to be unable to detect the very plain difference between them in this respect4 ,aldebaran has been called rose-red1 and it would be an interesting occupation for an amateur to determine1 with the aid of some proper color scale1 the precise hue of this star1 and of the many other stars which exhibit chromatic idiosyncrasy4 ,aldebaran is further interesting as being a standard first-magnitude star4 ,with the four-inch glass we see without difficulty the tenth-magnitude companion following ,aldebaran at a distance of #aad1 p4 #ce4 ,there is an almost inexplicable charm about these faint attendants of bright stars1 which is quite different from the interest attaching to a close and nearly equal pair4 ,the impression of physical relationship is never lacking though it may be deceptive1 and this awakens a lively appreciation of the vast differences of magnitude that exist among the different suns of space4 ,the actual size and might of this great red sun form an attractive subject for contemplation4 ,as it appears to our eyes ,aldebaran gives one twenty-five-thousand-millionth as much light as the sun1 but if we were placed midway between them the star would outshine the sun in the ratio of not less than #afj to #a4 ,and yet1 gigantic as it is1 ,aldebaran is possibly a pygmy in comparison with ,arcturus1 whose possible dimensions were discussed in the chapter relating to ,botes4 ,although ,aldebaran is known to possess several of the metallic elements that exist in the sun1 its spectrum differs widely from the solar spectrum in some respects1 and more closely resembles that of ,arcturus4 ,other interesting objects in ,taurus are sigma1 divisible with the naked eye1 magnitudes five and five and a half1 distance #g'2 ,sigma #fgd1 double1 magnitudes six and nine1 distance #aj4e1 p4 #adg2 ,sigma #gaf1 double1 magnitudes six and seven1 distance #e1 p4 #bjj--;a pleasing sight2 tau1 triple1 magnitudes four1 ten and a half1 and eleven1 distances #cf1 p4 #bdi1 and #cf1 p4 #fj--the ten-and-a-half-magnitude star is itself double1 as discovered by ,burnham2 star cluster ,no4 #ajcj1 not quite as broad as the moon1 and containing some stars as large as the eleventh magnitude2 and nebula ,no4 #aaeg1 the so-called ,crab nebula of ,lord ,rosse1 which our glasses will show only as a misty patch of faint light1 although large telescopes reveal in it a very curious structure4 ,illustration3 ,,map ,,no4 #bd4 ,we now turn to the cluster of circumpolar constellations sometimes called the ,royal ,family1 in allusion to the well-known story of the ,ethiopian king ,cepheus and his queen ,cassiopeia1 whose daughter ,andromeda was exposed on the seashore to be devoured by a monster1 but who was saved by the hero ,perseus4 ,all these mythologic personages are represented in the constellations that we are about to study4#d ,we begin with ,andromeda 7map ,no4 #bd74 ,the leading star alpha marks one corner of the great square of ,pegasus4 ,the first star of telescopic interest that we find in ,andromeda is 1 a double difficult on account of the faintness of the smaller component4 ,the magnitudes are four and eleven1 distance #di1 p4 #aaj4 ,a few degrees north of the naked eye detects a glimmering point where lies the ,great ,nebula in ,andromeda4 ,this is indicated on the map by the number #aaf4 ,with either of our three telescopes it is an interesting object1 but of course it is advisable to use our largest glass in order to get as much light as possible4 ,all that we can see is a long1 shuttle-shaped nebulous object1 having a brighter point near the center4 ,many stars are scattered over the field in its neighborhood1 but the nebula itself1 although its spectrum is peculiar in resembling that of a faint star1 is evidently a gaseous or at any rate a meteoritic mass1 since photographs show it to be composed of a series of imperfectly separated spirals surrounding a vast central condensation4 ,this peculiarity of the ,andromeda nebula1 which is invisible with telescopes although conspicuous in the photographs1 has1 since its discovery a few years ago1 given a great impetus to speculation concerning the transformation of nebul into stars and star clusters4 ,no one can look at a good photograph of this wonderful phenomenon without noticing its resemblance to the ideal state of things which1 according to the nebular hypothesis1 must once have existed in the solar system4 ,it is to be remembered1 however1 that there is probably sufficient material in the ,andromeda nebula to make a system many times1 perhaps hundreds or thousands of times1 as extensive as that of which our sun is the center4 ,if one contemplates this nebula only long enough to get a clear perception of the fact that creation was not ended when1 according to the ,mosaic history1 ,god1 having in six days finished the heavens and the earth and all the host of them1 rested from all his work1 a good blow will have been dealt for the cause of truth4 ,systems far vaster than ours are now in the bud1 and long before they have bloomed1 ambitious man1 who once dreamed that all these things were created to serve him1 will probably have vanished with the extinguishment of the little star whose radiant energy made his life and his achievements briefly possible4 #d ,for further details on this subject see ,astronomy with an ,opera-glass4 ,in ,august1 #ahhe1 a new star of magnitude six and a half made its appearance suddenly near the center of the ,andromeda nebula4 ,within one year it had disappeared1 having gradually dwindled until the great ,washington telescope1 then the largest in use1 no longer showed it4 ,that this was a phenomenon connected with the nebula is most probable1 but just what occurred to produce it nobody knows4 ,the observed appearances might have been produced by a collision1 and no better hypothesis has yet been suggested to account for them4 ,near the opposite end of the constellation from alpha we find the most interesting of triple stars in gamma4 ,the two larger components of this beautiful star are of magnitudes three and six1 distance #aj1 colors golden yellow and deep blue4 ,the three-inch shows them finely4 ,the smaller star is itself double1 its companion being of magnitude eight1 distance when discovered in #ahdb #j4e1 color bluish green4 ,a few years ago this third star got so close to its primary that it was invisible even with the highest powers of the great ,lick telescope1 but at present it is widening again4 ,in ,october1 #ahic1 ,i had the pleasure of looking at gamma ,andromed with the ,lick telescope1 and at that time it was possible just to separate the third star4 ,the angle seemed too small for certain measurement1 but a single setting of the micrometer by ,mr4 ,barnard1 to whose kindness ,i was indebted for my view of the star1 gave #j4ag as the approximate distance4 ,in #aijj the distance had increased to #j4d1 p4 #aae4 ,the brilliance of color contrast between the two larger stars of gamma ,andromed is hardly inferior to that exhibited in beta ,cygni1 so that this star may be regarded as one of the most picturesque of stellar objects for small telescopes4 ,other pleasing objects in this constellation are the binary star #cf1 magnitudes six and six and a half1 distance #a1 p4 #ag--the two stars are slowly closing and the five-inch glass is required to separate them3 the richly colored variable ,r1 which fades from magnitude five and a half to invisibility1 and then recovers its light in a period of about four hundred and five days2 and the bright star cluster #deg1 which covers a space about equal to the area of the full moon4 ,just south of the eastern end of ,andromeda is the small constellation ,triangulum1 or the ,triangles1 containing two interesting objects4 ,one of these is the beautiful little double #f1 magnitudes five and six1 distance #c4h1 p4 #gg1 colors yellow and blue2 and the other1 the nebula #ceb1 which equals in extent the star cluster in ,andromeda described above1 but nevertheless appears very faint with our largest glass4 ,its faintness1 however1 is not an indication of insignificance1 for to very powerful telescopes it exhibits a wonderful system of nuclei and spirals--another bit of chaos that is yielding by age-long steps to the influence of demiurgic forces4 ,a richer constellation than ,andromeda1 both for naked-eye and telescopic observation1 is ,perseus1 which is especially remarkable for its star clusters4 ,two of these1 #eab and #eba1 constitute the celebrated double cluster1 sometimes called the ,sword-hand of ,perseus1 and also chi ,persei4 ,to the smallest telescope this aggregation of stars1 ranging in magnitude from six and a half to fourteen1 and grouped about two neighboring centers1 presents a marvelous appearance4 ,as an educative object for those unaccustomed to celestial observations it may be compared among star clusters to beta ,cygni among double stars1 for the most indifferent spectator is struck with wonder in viewing it4 ,all the other clusters in ,perseus represented on the map are worth examining1 although none of them calls for special mention1 except perhaps #ehd1 where we may distinguish at least a hundred separate stars within an area less than one quarter as expansive as the face of the moon4 ,among the double stars of ,perseus we note first eta1 whose components are of magnitudes four and eight1 distance #bh1 colors white and pale blue4 ,the double epsilon is especially interesting on account of an alleged change of color from blue to red which the smaller star undergoes coincidently with a variation of brightness4 ,the magnitudes are three and eight1 distance #i1 p4 #i4 ,an interesting multiple is zeta1 two of whose stars at least we can see4 ,the magnitudes are three1 nine1 ten1 and ten1 distances #ac1 p4 #bjg1 #ij1 and #aab4 ,the chief attraction in ,perseus is the changeful and wonderful beta1 or ,algol1 the great typical star among the short-period variables4 ,during the greater part of its period this star is of magnitude two and two tenths1 but for a very short time1 following a rapid loss of light1 it remains at magnitude three and seven tenths4 ,the difference1 one magnitude and a half1 corresponds to an actual difference in brightness in the ratio of #c4ge to #a4 ,the entire loss of light during the declension occupies only four hours and a half4 ,the star remains at its faintest for a few minutes only before a perceptible gain of light occurs1 and the return to maximum is as rapid as was the preceding decline4 ,the period from one minimum to the next is two days twenty hours forty-eight minutes fifty-three seconds1 with an irregularity amounting to a few seconds in a year4 ,the ,arabs named the star ,algol1 or the ,demon1 on account of its eccentricity which did not escape their attention2 and when ,goodricke1 in #aghb1 applied a scientific method of observation to it1 the real cause of its variations was suggested by him1 but his explanation failed of general acceptance until its truth was established by ,prof4 ,e4 ,c4 ,pickering in #ahhj4 ,this explanation gives us a wonderful insight into stellar constitution4 ,according to it1 ,algol possesses a companion as large as the sun1 but invisible1 both because of its proximity to that star and because it yields no light1 and revolving in a plane horizontal to our line of sight4 ,the period of revolution is identical with the period of ,algol's cycle of variation1 and the diminution of light is caused by the interposition of the dark body as it sweeps along that part of its orbit lying between our point of view and the disk of ,algol4 ,in other words1 once in every two days twenty hours and forty-nine minutes ,algol1 as seen from the earth1 undergoes a partial eclipse4 ,in consequence of the great comparative mass of its dark companion1 ,algol itself moves in an orbit around their common center with a velocity quite sufficient to be detected by the shifting of the lines in its spectrum4 ,by means of data thus obtained the mass1 size1 and distance apart of ,algol and its singular comrade have been inferred4 ,the diameter of ,algol is believed to be about #a1abe1jjj miles1 that of the dark body about #hdj1jjj miles1 and the mean distance from center to center #c1bcj1jjj miles4 ,the density of both the light and the dark star is slight compared with that of the sun1 so that their combined mass is only two thirds as great as the sun's4 ,mention has been made of a slight irregularity in ,algol's period of variation4 ,basing his calculations upon this inequality1 ,dr4 ,chandler has put forward the hypothesis that there is another invisible body connected with ,algol1 and situated at a distance from it of about #a1hjj1jjj1jjj miles1 and that around this body1 which is far more massive than the others1 ,algol and its companions revolve in a period of one hundred and thirty years6 ,dr4 ,chandler has earned the right to have his hypotheses regarded with respect1 even when they are as extraordinary as that which has just been described4 ,it needs no indulgence of the imagination to lend interest to ,algol2 the simple facts are sufficient4 ,how did that bright star fall in with its black neighbors8 ,or were they created together8 ,illustration3 ,,map ,,no4 #be4 ,passing to the region covered by map ,no4 #be1 our eyes are caught by the curious figure1 formed by the five brightest stars of the constellation ,cassiopeia1 somewhat resembling the letter ,w4 ,like ,perseus1 this is a rich constellation1 both in star clusters and double stars4 ,among the latter we select as our first example sigma1 in which we find a combination of color that is at once very unusual and very striking--green and blue4 ,the magnitudes are five and seven1 distance #c1 p4 #cbd4 ,another beautiful colored double is eta1 whose magnitudes are four and seven and a half1 distance #e1 p4 #bjj1 colors white and purple4 ,this is one of the comparatively small number of stars the measure of whose distance has been attempted1 and a keen sense of the uncertainty of such measures is conveyed by the fact that authorities of apparently equal weight place eta ,cassiopei at such discordant distances as #abd1jjj1jjj1jjj1jjj miles1 #gj1jjj1jjj1jjj1jjj miles1 and #db1jjj1jjj1jjj1jjj miles4 ,it will be observed that the difference between the greatest and the least of these estimates is about double the entire distance given by the latter4 ,the same thing is practically true of the various attempts to ascertain the distance of the other stars which have a perceptible parallax1 even those which are evidently the nearest4 ,in some cases the later measures increase the distance1 in other cases they diminish it2 in no case is there anything like a complete accord4 ,yet of course we are not to infer that it is hopeless to learn anything about the distances of the stars4 ,with all their uncertainties and disagreements the few parallaxes we possess have laid a good foundation for a knowledge of the dimensions of at least the nearer parts of the universe4 ,we find an interesting triple in psi1 the magnitudes of the larger components being four and a half and eight and a half1 distance #cj4 ,the smaller star has a nine-and-a-half-magnitude companion1 distance #c4 ,a more beautiful triple is iota1 magnitudes four1 seven1 and eight1 distances #b1 p4 #bef1 and #g4e1 p4 #aab4 ,cassiopeia contains many star clusters1 three of which are indicated in the map4 ,of these #cib is perhaps the most interesting1 as it includes stars of many magnitudes1 among which are a red one of the eighth magnitude1 and a ninth-magnitude double whose components are #h apart4 ,not far from the star kappa we find the spot where the most brilliant temporary star on record made its appearance on ,november #aa1 #aegb4 ,tycho ,brahe studied this phenomenon during the entire period of its visibility1 which lasted until ,march1 #aegd4 ,it burst out suddenly with overpowering splendor1 far outshining every fixed star1 and even equaling ,venus at her brightest4 ,in a very short time it began to fade1 regularly diminishing in brightness1 and at the same time undergoing changes of color1 ending in red1 until it disappeared4 ,it has never been seen since1 and the suspicion once entertained that it was a variable with a period considerably exceeding three hundred years has not been confirmed4 ,there is a tenth-magnitude star near the place given by ,tycho as that occupied by the stranger4 ,many other faint stars are scattered about1 however1 and ,tycho's measures were not sufficiently exact to enable us to identify the precise position of his star4 ,if the phenomenon was due to a collision1 no reappearance of the star is to be expected4 ,camelopardalus is a very inconspicuous constellation1 yet it furnishes considerable occupation for the telescope4 ,sigma #cij1 of magnitude five1 has a companion of magnitude nine and a half1 distance #ae1 #afj4 ,sigma #che1 also of the fifth magnitude1 has a ninth-magnitude companion1 distance only #b4d1 p4 #afj4 ,according to some observers1 the larger star is yellow and the smaller white4 ,the star #a is a very pretty double1 magnitudes both six1 distance #aj4d4 ,its neighbor #b of magnitude six has an eighth-magnitude companion1 distance #a4g1 p4 #bgh4 ,the star #g of magnitude five is also double1 the companion of magnitude eight being distant only #a4b4 ,a glance at star cluster #idj1 which shows a slight central condensation1 completes our work in ,camelopardalus1 and we turn to ,ursa ,major1 represented in map ,no4 #bf4 ,here there are many interesting doubles and triples4 ,beginning with iota we find at once occupation for our largest glass4 ,the magnitudes are three and ten1 distance #aj1 p4 #ceg4 ,in the double star #bc the magnitudes are four and nine1 distance #bc1 p4 #bgb4 ,a more pleasing object is sigma#b1 a greenish fifth-magnitude star which has an eighth-magnitude companion1 distance #b4f1 p4 #bde4 ,a good double for our four-inch glass is xi1 whose magnitudes are four and five1 distance #a4hg1 p4 #ahc4 ,this is a binary with a period of revolution of about sixty years1 and is interesting as the first binary star whose orbit was determined4 ,savary calculated it in #ahbh4 ,near by is nu1 a difficult double1 magnitudes four and ten and a half1 distance #g1 p4 #adg4 ,in #eg we find again an easy double magnitudes six and eight1 distance #e4e1 p4 #d4 ,another similar double is #fe1 magnitudes six and eight1 distance #c4i1 p4 #ch4 ,a third star1 magnitude seven1 is seen at a distance of #aad from the primary4 ,we come now to ,ursa ,major's principal attraction zeta1 frequently called ,mizar4 ,the naked eye perceives near it a smaller star1 named ,alcor4 ,with the three-inch glass and a medium power we divide ,mizar into two bright stars brilliantly contrasted in color1 the larger being white and the smaller blue-green4 ,beside ,alcor1 several fainter stars are seen scattered over the field of view1 and1 taken all in all1 there are very few equally beautiful sights in the starry heavens4 ,the magnitudes of the double are three and four1 distance #ad4e1 p4 #adh4 ,the large star is again double1 although no telescope has been able to show it so1 its duplicity being revealed1 like that of beta ,aurig1 by the periodical splitting of the lines in its spectrum4 ,ursa ,major contains several nebul which may be glimpsed with telescopes of moderate dimensions4 ,an interesting pair of these objects1 both of which are included in one field of view1 is formed by #aidi and #aiej4 ,the first named is the brighter of the two1 its nucleus resembling a faint star4 ,the nebula #bcdc presents itself to us in the form of a faint1 hazy star1 but with large telescopes its appearance is very singular4 ,according to a picture made by ,lord ,rosse1 it bears no little resemblance to a skull1 there being two symmetrically placed holes in it1 each of which contains a star4 ,illustration3 ,,map ,,no4 #bf4 ,the portion of ,canes ,venatici1 represented in map ,no4 #bf1 contains two or three remarkable objects4 ,sigma #afjf is a close double1 magnitudes six and seven1 distance #a1 p4 #ccf4 ,it is a pretty sight with the five-inch4 ,the double star #b is singular in that its larger component is red and its smaller blue2 magnitudes six and eight1 distance #aa4d1 p4 #bfj4 ,still more beautiful is #ab1 commonly called ,cor ,caroli4 ,this double is wide1 and requires but a slight magnifying power4 ,the magnitudes are three and six1 distance #bj1 colors white or light yellow and blue4 ,the nebula #cegb1 although we can see it only as a pair of misty specks1 is in reality a very wonderful object4 ,lord ,rosse's telescope has revealed in it a complicated spiral structure1 recalling the photographs of the ,andromeda nebula1 and indicating that stupendous changes must be in process within it1 although our records of observation are necessarily too brief to bring out any perceptible alteration of figure4 ,it would seem that the astronomer has1 of all men1 the best reasons for complaining of the brevity of human life4 ,lastly1 we turn to ,ursa ,minor and the ,pole ,star4 ,the latter is a celebrated double1 not difficult1 except with a telescope of less than three inches aperture in the hands of an inexperienced observer4 ,the magnitudes are two and nine1 distance #ah4e4 ,the small star has a dull blue color4 ,in #ahii it was discovered by spectroscopic evidence that the ,pole ,star is triple4 ,in pi' we see a wide double1 magnitudes six and seven1 distance #cj1 p4 #hc4 ,this completes our survey of the starry heavens4 ,,chapter ,,viii ,,scenes ,,on ,,the ,,planets ,these starry globes far surpassed the earth in grandeur1 and the latter looked so diminutive that our empire1 which appeared only as a point on its surface1 awoke my pity4--,,cicero1 ,,the ,,dream ,,of ,,scipio4 ,although amateurs have played a conspicuous part in telescopic discovery among the heavenly bodies1 yet every owner of a small telescope should not expect to attach his name to a star4 ,but he certainly can do something perhaps more useful to himself and his friends2 he can follow the discoveries that others1 with better appliances and opportunities1 have made1 and can thus impart to those discoveries that sense of reality which only comes from seeing things with one's own eyes4 ,there are hundreds of things continually referred to in books and writings on astronomy which have but a misty and uncertain significance for the mere reader1 but which he can easily verify for himself with the aid of a telescope of four or five inches aperture1 and which1 when actually confronted by the senses1 assume a meaning1 a beauty1 and an importance that would otherwise entirely have escaped him4 ,henceforth every allusion to the objects he has seen is eloquent with intelligence and suggestion4 ,take1 for instance1 the planets that have been the subject of so many observations and speculations of late years--,mars1 ,jupiter1 ,saturn1 ,venus4 ,for the ordinary reader much that is said about them makes very little impression upon his mind1 and is almost unintelligible4 ,he reads of the snow patches on ,mars1 but unless he has actually seen the whitened poles of that planet he can form no clear image in his mind of what is meant4 ,so the belts of ,jupiter is a confusing and misleading phrase for almost everybody except the astronomer1 and the rings of ,saturn are beyond comprehension unless they have actually been seen4 ,it is true that pictures and photographs partially supply the place of observation1 but by no means so successfully as many imagine4 ,the most realistic drawings and the sharpest photographs in astronomy are those of the moon1 yet ,i think nobody would maintain that any picture in existence is capable of imparting a really satisfactory visual impression of the appearance of the lunar globe4 ,nobody who has not seen the moon with a telescope--it need not be a large one--can form a correct and definite idea of what the moon is like4 ,the satisfaction of viewing with one's own eyes some of the things the astronomers write and talk about is very great1 and the illumination that comes from such viewing is equally great4 ,just as in foreign travel the actual seeing of a famous city1 a great gallery filled with masterpieces1 or a battlefield where decisive issues have been fought out illuminates1 for the traveler's mind1 the events of history1 the criticisms of artists1 and the occurrences of contemporary life in foreign lands1 so an acquaintance with the sights of the heavens gives a grasp on astronomical problems that can not be acquired in any other way4 ,the person who has been in ,rome1 though he may be no archologist1 gets a far more vivid conception of a new discovery in the ,forum than does the reader who has never seen the city of the ,seven ,hills2 and the amateur who has looked at ,jupiter with a telescope1 though he may be no astronomer1 finds that the announcement of some change among the wonderful belts of that cloudy planet has for him a meaning and an interest in which the ordinary reader can not share4 ,illustration3 ,,jupiter ,,seen ,,with ,a ,,five-,,inch ,,telescope4 ,shadow of a satellite visible4 ,jupiter is perhaps the easiest of all the planets for the amateur observer4 ,a three-inch telescope gives beautiful views of the great planet1 although a four-inch or a five-inch is of course better4 ,but there is no necessity for going beyond six inches' aperture in any case4 ,for myself1 ,i should care for nothing better than my ,byrne five-inch of fifty-two inches' focal distance4 ,with such a glass more details are visible in the dark belts and along the bright equatorial girdle than can be correctly represented in a sketch before the rotation of the planet has altered their aspect1 while the shadows of the satellites thrown upon the broad disk1 and the satellites themselves when in transit1 can be seen sometimes with exquisite clearness4 ,the contrasting colors of various parts of the disk are also easily studied with a glass of four or five inches' aperture4 ,there is a charm about the great planet when he rides high in a clear evening sky1 lording it over the fixed stars with his serene1 unflickering luminousness1 which no possessor of a telescope can resist4 ,you turn the glass upon him and he floats into the field of view1 with his cortge of satellites1 like a yellow-and-red moon1 attended by four miniatures of itself4 ,you instantly comprehend ,jupiter's mastery over his satellites--their allegiance is evident4 ,no one would for an instant mistake them for stars accidentally seen in the same field of view4 ,although it requires a very large telescope to magnify their disks to measurable dimensions1 yet the smallest glass differentiates them at once from the fixed stars4 ,there is something almost startling in their appearance of companionship with the huge planet--this sudden verification to your eyes of the laws of gravitation and of central forces4 ,it is easy1 while looking at ,jupiter amid his family1 to understand the consternation of the churchmen when ,galileo's telescope revealed that miniature of the solar system1 and it is gratifying to gaze upon one of the first battle grounds whereon science gained a decisive victory for truth4 ,the swift changing of place among the satellites1 as well as the rapidity of ,jupiter's axial rotation1 give the attraction of visible movement to the ,jovian spectacle4 ,the planet rotates in four or five minutes less than ten hours--in other words1 it makes two turns and four tenths of a third turn while the earth is rolling once upon its axis4 ,a point on ,jupiter's equator moves about twenty-seven thousand miles1 or considerably more than the entire circumference of the earth1 in a single hour4 ,the effect of this motion is clearly perceptible to the observer with a telescope on account of the diversified markings and colors of the moving disk1 and to watch it is one of the greatest pleasures that the telescope affords4 ,it would be possible1 when the planet is favorably situated1 to witness an entire rotation of ,jupiter in the course of one night1 but the beginning and end of the observation would be more or less interfered with by the effects of low altitude1 to say nothing of the tedium of so long a vigil4 ,but by looking at the planet for an hour at a time in the course of a few nights every side of it will have been presented to view4 ,suppose the first observation is made between nine and ten o'clock on any night which may have been selected4 ,then on the following night between ten and eleven o'clock ,jupiter will have made two and a half turns upon his axis1 and the side diametrically opposite to that seen on the first night will be visible4 ,on the third night between eleven and twelve o'clock ,jupiter will have performed five complete rotations1 and the side originally viewed will be visible again4 ,owing to the rotundity of the planet1 only the central part of the disk is sharply defined1 and markings which can be easily seen when centrally located become indistinct or disappear altogether when near the limb4 ,approach to the edge of the disk also causes a foreshortening which sometimes entirely alters the aspect of a marking4 ,it is advisable1 therefore1 to confine the attention mainly to the middle of the disk4 ,as time passes1 clearly defined markings on or between the cloudy belts will be seen to approach the western edge of the disk1 gradually losing their distinctness and altering their appearance1 while from the region of indistinct definition near the eastern edge other markings slowly emerge and advance toward the center1 becoming sharper in outline and more clearly defined in color as they swing into view4 ,watching these changes1 the observer is carried away by the reflection that he actually sees the turning of another distant world upon its axis of rotation1 just as he might view the revolving earth from a standpoint on the moon4 ,belts of reddish clouds1 many thousands of miles across1 are stretched along on each side of the equator of the great planet he is watching2 the equatorial belt itself1 brilliantly lemon-hued1 or sometimes ruddy1 is diversified with white globular and balloon-shaped masses1 which almost recall the appearance of summer cloud domes hanging over a terrestrial landscape1 while toward the poles shadowy expanses of gradually deepening blue or blue-gray suggest the comparative coolness of those regions which lie always under a low sun4 ,illustration3 ,,eclipses ,,and ,,transits ,,of ,,jupiter',s ,,satellites4 ,satellite ,i and the shadow of ,,iii are seen in transit4 ,,iv is about to be eclipsed4 ,after a few nights' observation even the veriest amateur finds himself recognizing certain shapes or appearances--a narrow dark belt running slopingly across the equator from one of the main cloud zones to the other1 or a rift in one of the colored bands1 or a rotund white mass apparently floating above the equator1 or a broad scallop in the edge of a belt like that near the site of the celebrated red spot1 whose changes of color and aspect since its first appearance in #ahgh1 together with the light it has thrown on the constitution of ,jupiter's disk1 have all but created a new ,jovian literature1 so thoroughly and so frequently have they been discussed4 ,and1 having noticed these recurring features1 the observer will begin to note their relations to one another1 and will thus be led to observe that some of them gradually drift apart1 while others drift nearer2 and after a time1 without any aid from books or hints from observatories1 he will discover for himself that there is a law governing the movements on ,jupiter's disk4 ,upon the whole he will find that the swiftest motions are near the equator1 and the slowest near the poles1 although1 if he is persistent and has a good eye and a good instrument1 he will note exceptions to this rule1 probably arising1 as ,professor ,hough suggests1 from differences of altitude in ,jupiter's atmosphere4 ,finally1 he will conclude that the colossal globe before him is1 exteriorly at least1 a vast ball of clouds and vapors1 subject to tremendous vicissitudes1 possibly intensely heated1 and altogether different in its physical constitution1 although made up of similar elements1 from the earth4 ,then1 if he chooses1 he can sail off into the delightful cloud-land of astronomical speculation1 and make of the striped and spotted sphere of ,jove just such a world as may please his fancy--for a world of some kind it certainly is4 ,for many observers the satellites of ,jupiter possess even greater attractions than the gigantic ball itself4 ,as ,i have already remarked1 their movements are very noticeable and lend a wonderful animation to the scene4 ,although they bear classical names1 they are almost universally referred to by their ,roman numbers1 beginning with the innermost1 whose symbol is ,i1 and running outward in regular order ,,ii1 ,,iii1 and ,,iv4#e ,the minute satellite much nearer to the planet than any of the others1 which ,mr4 ,barnard discovered with the ,lick telescope in #ahib1 is called the fifth1 although in the order of distance it would be the first4 ,in size and importance1 however1 it can not rank with its comparatively gigantic brothers4 ,of course1 no amateur's telescope can afford the faintest glimpse of it4 #e ,their names1 in the same order as their numbers1 are ,io1 ,europa1 ,ganymede1 and ,callisto4 ,satellite ,i1 situated at a mean distance of #bfa1jjj miles from ,jupiter's center--about #bb1jjj miles farther than the moon is from the earth--is urged by its master's overpowering attraction to a speed of #cbj miles per minute1 so that it performs a complete revolution in about forty-two hours and a half4 ,the others1 of course1 move more slowly1 but even the most distant performs its revolution in several hours less than sixteen days4 ,the plane of their orbits is presented edgewise toward the earth1 from which it follows that they appear to move back and forth nearly in straight lines1 some apparently approaching the planet1 while others are receding from it4 ,the changes in their relative positions1 which can be detected from hour to hour1 are very striking night after night1 and lead to a great variety of arrangements always pleasing to the eye4 ,the most interesting phenomena that they present are their transits and those of their round1 black shadows across the face of the planet2 their eclipses by the planet's shadow1 when they disappear and afterward reappear with astonishing suddenness2 and their occultations by the globe of ,jupiter4 ,upon the whole1 the most interesting thing for the amateur to watch is the passage of the shadows across ,jupiter4 ,the distinctness with which they can be seen when the air is steady is likely to surprise1 as it is certain to delight1 the observer4 ,when it falls upon a light part of the disk the shadow of a satellite is as black and sharply outlined as a drop of ink2 on a dark-colored belt it can not so easily be seen4 ,it is more difficult to see the satellites themselves in transit4 ,there appears to be some difference among them as to visibility in such circumstances4 ,owing to their luminosity they are best seen when they have a dark belt for a background1 and are least easily visible when they appear against a bright portion of the planet4 ,every observer should provide himself with a copy of the ,american ,ephemeris for the current year1 wherein he will find all the information needed to enable him to identify the various satellites and to predict1 by turning ,washington mean time into his own local time1 the various phenomena of the transits and eclipses4 ,while a faithful study of the phenomena of ,jupiter is likely to lead the student to the conclusion that the greatest planet in our system is not a suitable abode for life1 yet the problem of its future1 always fascinating to the imagination1 is open2 and whosoever may be disposed to record his observations in a systematic manner may at least hope to render aid in the solution of that problem4 ,saturn ranks next to ,jupiter in attractiveness for the observer with a telescope4 ,the rings are almost as mystifying to-day as they were in the time of ,herschel4 ,there is probably no single telescopic view that can compare in the power to excite wonder with that of ,saturn when the ring system is not so widely opened but that both poles of the planet project beyond it4 ,one returns to it again and again with unflagging interest1 and the beauty of the spectacle quite matches its singularity4 ,when ,saturn is in view the owner of a telescope may become a recruiting officer for astronomy by simply inviting his friends to gaze at the wonderful planet4 ,the silvery color of the ball1 delicately chased with half-visible shadings1 merging one into another from the bright equatorial band to the bluish polar caps2 the grand arch of the rings1 sweeping across the planet with a perceptible edging of shadow2 their sudden disappearance close to the margin of the ball1 where they go behind it and fall straightway into night2 the manifest contrast of brightness1 if not of color1 between the two principal rings2 the fine curve of the black line marking the #a1fjj-mile gap between their edges--these are some of the elements of a picture that can never fade from the memory of any one who has once beheld it in its full glory4 ,illustration3 ,,saturn ,,seen ,,with ,a ,,five-,,inch ,,telescope4 ,saturn's moons are by no means so interesting to watch as are those of ,jupiter4 ,even the effect of their surprising number 7raised to nine by ,professor ,pickering's discovery in #ahii of a new one which is almost at the limit of visibility1 and was found only with the aid of photography7 is lost1 because most of them are too faint to be seen with ordinary telescopes1 or1 if seen1 to make any notable impression upon the eye4 ,the two largest--,titan and ,japetus--are easily found1 and ,titan is conspicuous1 but they give none of that sense of companionship and obedience to a central authority which strikes even the careless observer of ,jupiter's system4 ,this is owing partly to their more deliberate movements and partly to the inclination of the plane of their orbits1 which seldom lies edgewise toward the earth4 ,illustration3 ,,polar ,,view ,,of ,,saturn',s ,,system4 ,the orbits of the five nearest satellites are shown4 ,the dotted line outside the rings shows ,roche's limit4 ,but the charm of the peerless rings is abiding1 and the interest of the spectator is heightened by recalling what science has recently established as to their composition4 ,it is marvelous to think1 while looking upon their broad1 level surfaces--as smooth1 apparently1 as polished steel1 though thirty thousand miles across--that they are in reality vast circling currents of meteoritic particles or dust1 through which run immense waves1 condensation and rarefaction succeeding one another as in the undulations of sound4 ,yet1 with all their inferential tumult1 they may actually be as soundless as the depths of interstellar space1 for ,struve has shown that those spectacular rings possess no appreciable mass1 and1 viewed from ,saturn itself1 their 7to us7 gorgeous seeming bow may appear only as a wreath of shimmering vapor spanning the sky and paled by the rivalry of the brighter stars4 ,in view of the theory of tidal action disrupting a satellite within a critical distance from the center of its primary1 the thoughtful observer of ,saturn will find himself wondering what may have been the origin of the rings4 ,the critical distance referred to1 and which is known as ,roche's limit1 lies1 according to the most trustworthy estimates1 just outside the outermost edge of the rings4 ,it follows that if the matter composing the rings were collected into a single body that body would inevitably be torn to pieces and scattered into rings2 and so1 too1 if instead of one there were several or many bodies of considerable size occupying the place of the rings1 all of these bodies would be disrupted and scattered4 ,if one of the present moons of ,saturn--for instance1 ,mimas1 the innermost hitherto discovered--should wander within the magic circle of ,roche's limit it would suffer a similar fate1 and its particles would be disseminated among the rings4 ,one can hardly help wondering whether the rings have originated from the demolition of satellites--,saturn devouring his children1 as the ancient myths represent1 and encircling himself1 amid the fury of destruction1 with the dust of his disintegrated victims4 ,at any rate1 the amateur student of ,saturn will find in the revelations of his telescope the inspirations of poetry as well as those of science1 and the bent of his mind will determine which he shall follow4 ,professor ,pickering's discovery of a ninth satellite of ,saturn1 situated at the great distance of nearly eight million miles from the planet1 serves to call attention to the vastness of the sphere of activity over which the ringed planet reigns4 ,surprising as the distance of the new satellite appears when compared with that of our moon1 it is yet far from the limit where ,saturn's control ceases and that of the sun becomes predominant4 ,that limit1 according to ,prof4 ,asaph ,hall's calculation1 is nearly #cj1jjj1jjj miles from ,saturn's center1 while if our moon were removed to a distance a little exceeding #ejj1jjj miles the earth would be in danger of losing its satellite through the elopement of ,artemis with ,apollo4 ,although1 as already remarked1 the satellites of ,saturn are not especially interesting to the amateur telescopist1 yet it may be well to mention that1 in addition to ,titan and ,japetus1 the satellite named ,rhea1 the fifth in order of distance from the planet1 is not a difficult object for a three-or four-inch telescope1 and two others considerably fainter than ,rhea--,dione 7the fourth7 and ,tethys 7the third7--may be seen in favorable circumstances4 ,the others--,mimas 7the first71 ,enceladus 7the second71 and ,hyperion 7the seventh7--are beyond the reach of all but large telescopes4 ,the ninth satellite1 which has received the name of ,phoebe1 is much fainter than any of the others1 its stellar magnitude being reckoned by its discoverer at about #ae4e4 ,mars1 the best advertised of all the planets1 is nearly the least satisfactory to look at except during a favorable opposition1 like those of #ahgg and #ahib1 when its comparative nearness to the earth renders some of its characteristic features visible in a small telescope4 ,the next favorable opposition will occur in #aijg4 ,when well seen with an ordinary telescope1 say a four-or five-inch glass1 ,mars shows three peculiarities that may be called fairly conspicuous--viz41 its white polar cap1 its general reddish1 or orange-yellow1 hue1 and its dark markings1 one of the clearest of which is the so-called ,syrtis ,major1 or1 as it was once named on account of its shape1 ,hourglass ,sea4 ,other dark expanses in the southern hemisphere are not difficult to be seen1 although their outlines are more or less misty and indistinct4 ,the gradual diminution of the polar cap1 which certainly behaves in this respect as a mass of snow and ice would do1 is a most interesting spectacle4 ,as summer advances in the southern hemisphere of ,mars1 the white circular patch surrounding the pole becomes smaller1 night after night1 until it sometimes disappears entirely even from the ken of the largest telescopes4 ,at the same time the dark expanses become more distinct1 as if the melting of the polar snows had supplied them with a greater depth of water1 or the advance of the season had darkened them with a heavier growth of vegetation4 ,illustration3 ,,mars ,,seen ,,with ,a ,,five-,,inch ,,telescope4 ,the phenomena mentioned above are about all that a small telescope will reveal4 ,occasionally a dark streak1 which large instruments show is connected with the mysterious system of canals1 can be detected1 but the canals themselves are far beyond the reach of any telescope except a few of the giants handled by experienced observers4 ,the conviction which seems to have forced its way into the minds even of some conservative astronomers1 that on ,mars the conditions1 to use the expression of ,professor ,young1 are more nearly earthlike than on any other of the heavenly bodies which we can see with our present telescopes1 is sufficient to make the planet a center of undying interest notwithstanding the difficulties with which the amateur is confronted in his endeavors to see the details of its markings4 ,,the ,,illumination ,,of ,,venus',s ,,atmosphere ,,at ,,the ,,beginning ,,of ,,her ,,transit ,,across ,,the ,,sun4 ,in ,venus the fatal gift of beauty may be said1 as far as our observations are concerned1 to be matched by the equally fatal gift of brilliance4 ,whether it be due to atmospheric reflection alone or to the prevalence of clouds1 ,venus is so bright that considerable doubt exists as to the actual visibility of any permanent markings on her surface4 ,the detailed representations of the disk of ,venus by ,mr4 ,percival ,lowell1 showing in some respects a resemblance to the stripings of ,mars1 can not yet be accepted as decisive4 ,more experienced astronomers than ,mr4 ,lowell have been unable to see at all things which he draws with a fearless and unhesitating pencil4 ,that there are some shadowy features of the planet's surface to be seen in favourable circumstances is probable1 but the time for drawing a map of ,venus has not yet come4 ,the previous work of ,schiaparelli lends a certain degree of probability to ,mr4 ,lowell's observations on the rotation of ,venus4 ,this rotation1 according to the original announcement of ,schiaparelli1 is probably performed in the same period as the revolution around the sun4 ,in other words1 ,venus1 if ,schiaparelli and ,lowell are right1 always presents the same side to the sun1 possessing1 in consequence1 a day hemisphere and a night hemisphere which never interchange places4 ,this condition is so antagonistic to all our ideas of what constitutes habitability for a planet that one hesitates to accept it as proved1 and almost hopes that it may turn out to have no real existence4 ,venus1 as the twin of the earth in size1 is a planet which the imagination1 warmed by its sunny aspect1 would fain people with intelligent beings a little fairer than ourselves2 but how can such ideas be reconciled with the picture of a world one half of which is subjected to the merciless rays of a never-setting sun1 while the other half is buried in the fearful gloom and icy chill of unending night8 ,any amateur observer who wishes to test his eyesight and his telescope in the search of shades or markings on the disk of ,venus by the aid of which the question of its rotation may finally be settled should do his work while the sun is still above the horizon4 ,schiaparelli adopted that plan years ago1 and others have followed him with advantage4 ,the diffused light of day serves to take off the glare which is so serious an obstacle to the successful observation of ,venus when seen against a dark sky4 ,knowing the location of ,venus in the sky1 which can be ascertained from the ,ephemeris1 the observer can find it by day4 ,if his telescope is not permanently mounted and provided with circles this may not prove an easy thing to do1 yet a little perseverance and ingenuity will effect it4 ,one way is to find1 with a star chart1 some star whose declination is the same1 or very nearly the same1 as that of ,venus1 and which crosses the meridian say twelve hours ahead of her4 ,then set the telescope upon that star1 when it is on the meridian at night1 and leave it there1 and the next day1 twelve hours after the star crossed the meridian1 look into your telescope and you will see ,venus1 or1 if not1 a slight motion of the tube will bring her into view4 ,for many amateurs the phases of ,venus will alone supply sufficient interest for telescopic observation4 ,the changes in her form1 from that of a round full moon when she is near superior conjunction to the gibbous1 and finally the half-moon phase as she approaches her eastern elongation1 followed by the gradually narrowing and lengthening crescent1 until she is a mere silver sickle between the sun and the earth1 form a succession of delightful pictures4 ,not very much can be said for ,mercury as a telescopic object4 ,the little planet presents phases like those of ,venus1 and1 according to ,schiaparelli and ,lowell1 it resembles ,venus in its rotation1 keeping always the same side to the sun4 ,in fact1 ,schiaparelli's discovery of this peculiarity in the case of ,mercury preceded the similar discovery in the case of ,venus4 ,there are markings on ,mercury which have reminded some astronomers of the moon1 and there are reasons for thinking that the planet can not be a suitable abode for living beings1 at least for beings resembling the inhabitants of the earth4 ,uranus and ,neptune are too far away to present any attraction for amateur observers4 ,,chapter ,,ix ,,the ,,mountains ,,and ,,plains ,,of ,,the ,,moon1 ,,and ,,the ,,spectacles ,,of ,,the ,,sun 444 the ,moon1 whose orb ,the ,tuscan artist views through optic glass ,at evening from the top of ,fesol1 ,or in ,valdarno1 to descry new lands1 ,rivers or mountains in her spotty globe4--,,paradise ,,lost4 ,the moon is probably the most interesting of all telescopic objects4 ,this arises from its comparative nearness to the earth4 ,a telescope magnifying #a1jjj diameters brings the moon within an apparent distance of less than #bdj miles4 ,if telescopes are ever made with a magnifying power of #aj1jjj diameters1 then1 provided that atmospheric difficulties can be overcome1 we shall see the moon as if it were only about twenty miles off1 and a sensitive astronomer might be imagined to feel a little hesitation about gazing so closely at the moon--as if he were peering into a neighbor world's window4 ,but a great telescope and a high magnifying power are not required to interest the amateur astronomer in the study of the moon4 ,our three-inch telescope is amply sufficient to furnish us with entertainment for many an evening while the moon is running through its phases1 and we shall find delight in frequently changing the magnifying power as we watch the lunar landscapes1 because every change will present them in a different aspect4 ,it should be remembered that a telescope1 unless a terrestrial eyepiece or prism is employed1 reverses such an object as the moon top for bottom4 ,accordingly1 if the moon is on or near the meridian when the observations are made1 we shall see the north polar region at the bottom and the south polar region at the top4 ,in other words1 the face of the moon as presented in the telescope will be upside down1 north and south interchanging places as compared with their positions in a geographical map4 ,but east and west remain unaltered in position1 as compared with such a map--i4 e41 the eastern hemisphere of the moon is seen on the right and the western hemisphere on the left4 ,it is the moon's western edge that catches the first sunlight when new moon begins1 and1 as the phase increases1 passing into first quarter and from that to full moon1 the illumination sweeps across the disk from west to east4 ,illustration3 ,,lunar ,,chart ,,no4 #a1 ,,northwest ,,quarter4 ,the narrow sickle of the new moon1 hanging above the sunset1 is a charming telescopic sight4 ,use a low power1 and observe the contrast between the bright1 smooth round of the sunward edge1 which has almost the polish of a golden rim1 and the irregular and delicately shaded inner curve1 where the adjacent mountains and plains picturesquely reflect or subdue the sunshine4 ,while the crescent grows broader new objects are continually coming into view as the sun rises upon them1 until at length one of the most conspicuous and remarkable of the lunar seas1 the ,mare ,crisium1 or ,sea of ,crises1 lies fully displayed amid its encircling peaks1 precipices1 and craters4 ,the ,mare ,crisium is all in the sunlight between the third and fourth day after new moon4 ,it is about #cej by #bhj miles in extent1 and if ever filled with water must have been a very deep sea1 since its arid bed lies at a great but not precisely ascertained depth below the general level of the moon4 ,there are a few small craters on the floor of the ,mare ,crisium1 the largest bearing the name of ,picard1 and its borders are rugged with mountains4 ,on the southwestern side is a lofty promontory1 #aa1jjj feet in height1 called ,cape ,agarum4 ,at the middle of the eastern side a kind of bay opens deep in the mountains1 whose range here becomes very narrow4 ,southeast of this bay lies a conspicuous bright point1 the crater mountain ,proclus1 on which the sun has fully risen in the fourth day of the moon1 and which reflects the light with extraordinary liveliness4 ,adjoining ,proclus on the east and south is a curious1 lozenge-shaped flat1 broken with short1 low ridges1 and possessing a most peculiar light-brown tint1 easily distinguished from the general color tone of the lunar landscapes4 ,it would be interesting to know what was passing in the mind of the old astronomer who named this singular region ,palus ,somnii4 ,it is not the only spot on the moon which has been called a marsh1 and to which an unexplained connection with dreams has been ascribed4 ,nearly on the same meridian with ,proclus1 at a distance of about a hundred miles northward1 lies a fine example of a ring mountain1 rather more than forty miles in diameter1 and with peak-tipped walls which in some places are #ac1jjj feet in height1 as measured from the floor within4 ,this is ,macrobius4 ,there is an inconspicuous central mountain in the ring4 ,north of the ,mare ,crisium1 and northwest of ,macrobius1 we find a much larger mountain ring1 oblong in shape and nearly eighty miles in its greatest diameter4 ,it is named ,cleomenes4 ,the highest point on its wall is about #aj1jjj feet above the interior4 ,near the northeast corner of the wall yawns a huge and very deep crater1 ,tralles1 while at the northern end is another oblong crater mountain called ,burckhardt4 ,from ,cleomenes northward to the pole1 or to the northern extremity of the crescent1 if our observations are made during new moon1 the ground appears broken with an immense number of ridges1 craters1 and mountain rings1 among which we may telescopically wander at will4 ,one of the more remarkable of these objects1 which may be identified with the aid of ,lunar ,chart ,no4 #a1 is the vast ringed plain near the edge of the disk1 named ,gauss4 ,it is more than a hundred and ten miles in diameter4 ,owing to its situation1 so far down the side of the lunar globe1 it is foreshortened into a long ellipse1 although in reality it is nearly a circle4 ,a chain of mountains runs north and south across the interior plain4 ,geminus1 ,berzelius1 and ,messala are other rings well worth looking at4 ,the remarkable pair called ,atlas and ,hercules demand more than passing attention4 ,the former is fifty-five and the latter forty-six miles in diameter4 ,each sinks #aa1jjj feet below the summit of the loftiest peak on its encircling wall4 ,both are full of interesting detail sufficient to occupy the careful observer for many nights4 ,the broad ring bearing the name of ,endymion is nearly eighty miles in diameter1 and has one peak #ae1jjj feet high4 ,the interior plain is flat and dark4 ,beyond ,endymion on the edge of the disk is part of a gloomy plain called the ,mare ,humboltianum4 ,after glancing at the crater-shaped mountains on the western and southern border of the ,mare ,crisium1 ,alhazen1 ,hansen1 ,condorcet1 ,firmicus1 etc41 we pass southward into the area covered in ,lunar ,chart ,no4 #b4 ,the long dark plain south of the ,mare ,crisium is the ,mare ,fecunditatis1 though why it should have been supposed to be particularly fecund1 or fertile1 is by no means clear4 ,on the western border of this plain1 about three hundred miles from the southern end of the ,mare ,crisium1 is the mountain ring1 or circumvallation1 called ,langrenus1 about ninety miles across and in places #aj1jjj feet high4 ,there is a fine central mountain with a number of peaks4 ,nearly a hundred miles farther south1 on the same meridian1 lies an equally extensive mountain ring named ,vendelinus4 ,the broken and complicated appearance of its northern walls will command the observer's attention4 ,another similar step southward1 and still on the same meridian brings us to a yet finer mountain ring1 slightly larger than the others1 and still more complicated in its walls1 peaks1 and terraces1 and in its surroundings of craters1 gorges1 and broken ridges4 ,this is ,petavius4 ,west of ,petavius1 on the very edge of the disk1 is a wonderful formation1 a walled plain named ,humboldt1 which is looked down upon at one point near its eastern edge by a peak #af1jjj feet in height4 ,about a hundred and forty miles south of ,petavius is the fourth great mountain ring lying on the same meridian4 ,its name is ,furnerius4 ,look particularly at the brilliantly shining crater on the northeast slope of the outer wall of ,furnerius4 ,illustration3 ,,lunar ,,chart ,,no4 #b1 ,,southwest ,,quarter4 ,suppose that our observations are now interrupted1 to be resumed when the moon1 about seven days old1 is in its first quarter4 ,if we had time1 it would be a most interesting thing to watch the advance of the lunar sunrise every night1 for new beauties are displayed almost from hour to hour2 but1 for the purposes of our description it is necessary to curtail the observations4 ,at first quarter one half of the lunar hemisphere which faces the earth is illuminated by the sun1 and the line of sunrise runs across some of the most wonderful regions of the moon4 ,we begin1 referring once more to ,lunar ,chart ,no4 #a1 in the neighborhood of the north pole of the moon4 ,here the line along which day and night meet is twisted and broken1 owing to the roughness of the lunar surface4 ,about fifteen degrees southwest of the pole lies a remarkable square-cornered1 mountain-bordered plain1 about forty miles in length1 called ,barrow4 ,very close to the pole is a ring mountain1 about twenty-five miles in diameter1 whose two loftiest peaks1 #h1jjj to #i1jjj feet high1 according to ,neison1 must1 from their situation1 enjoy perpetual day4 ,the long1 narrow1 dark plain1 whose nearest edge is about thirty degrees south of the pole1 is the ,mare ,frigoris1 bordered on both sides by uplands and mountains4 ,at its southern edge we find the magnificent ,aristoteles1 a mountain ring1 sixty miles across1 whose immense wall is composed of terraces and ridges running up to lofty peaks1 which rise nearly #aa1jjj feet above the floor of the valley4 ,about a hundred miles south of ,aristoteles is ,eudoxus1 another fine mountain ring1 forty miles in diameter1 and quite as deep as its northern neighbor4 ,these two make a most striking spectacle4 ,we are now in the neighborhood of the greatest mountain chains on the moon1 the lunar ,alps lying to the east and the lunar ,caucasus to the south of ,aristoteles and ,eudoxus1 while still farther south1 separated from the ,caucasus by a strait not more than a hundred miles broad1 begins the mighty range of the lunar ,apennines4 ,we first turn the telescope on the ,alps4 ,as the line of sunrise runs directly across their highest peaks1 the effect is startling4 ,the greatest elevations are about #ab1jjj feet4 ,the observer's eye is instantly caught by a great valley1 running like a furrow through the center of the mountain mass1 and about eighty or ninety miles in length4 ,the sealike expanse south and southeast of the ,alps is the ,mare ,imbrium1 and it is along the coast of this so-called sea that the ,alps attain their greatest height4 ,the valley1 or gorge1 above mentioned1 appears to cut through the loftiest mountains and to reach the coast1 although it is so narrowed and broken among the greater peaks that its southern portion is almost lost before it actually reaches the ,mare ,imbrium4 ,opening wider again as it enters the ,mare1 it forms a deep bay among precipitous mountains4 ,the ,caucasus ,mountains are not so lofty nor so precipitous as the ,alps1 and consequently have less attraction for the observer4 ,they border the dark1 oval plain of the ,mare ,serenitatis on its northeastern side4 ,the great bay running out from the ,mare toward the northwest1 between the ,caucasus and the huge mountain ring of ,posidonius1 bears the fanciful name of ,lacus ,somniorum4 ,in the old days when the moon was supposed to be inhabited1 those terrestrial godfathers1 led by the astronomer ,riccioli1 who were busy bestowing names upon the seas and mountains of our patient satellite1 may have pleased their imagination by picturing this arm of the ,serene ,sea as a peculiarly romantic sheet of water1 amid whose magical influences the lunar gentlefolk1 drifting softly in their silver galleons and barges1 and enjoying the splendors of full earth poured upon their delightful little world1 were accustomed to fall into charming reveries1 as even we hard-headed sons of ,adam occasionally do when the waters under the keel are calm and smooth and the balmy air of a moonlit night invokes the twin spirits of poetry and music4 ,posidonius1 the dominating feature of the shore line here1 is an extraordinary example of the many formations on the moon which are so different from everything on the earth that astronomers do not find it easy to bestow upon them names that truly describe them4 ,it may be called a ring mountain or a ringed plain1 for it is both4 ,its diameter exceeds sixty miles1 and the interior plain lies about #b1jjj feet below the outer surface of the lunar ground4 ,the mountain wall surrounding the ring is by no means remarkable for elevation1 its greatest height not exceeding #f1jjj feet1 but1 owing to the broad sweep of the curved walls1 the brightness of the plain they inclose1 and the picturesque irregularity of the silhouette of shadow thrown upon the valley floor by the peaks encircling it1 the effect produced upon the observer is very striking and attractive4 ,having finished with ,posidonius and glanced across the broken region of the ,taurus ,mountains toward the west1 we turn next to consider the ,mare ,serenitatis4 ,this broad gray plain1 which1 with a slight magnifying power1 certainly looks enough like a sea to justify the first telescopists in thinking that it might contain water1 is about #dcj by #dbe miles in extent1 its area being #abe1jjj square miles4 ,running directly through its middle1 nearly in a north and south line1 is a light streak1 which even a good opera glass shows4 ,this streak is the largest and most wonderful of the many similar rays which extend on all sides from the great crater1 or ring1 of ,tycho in the southern hemisphere4 ,the ray in question is more than #b1jjj miles long1 and1 like its shorter congeners1 it turns aside for nothing2 neither sea1 nor peak1 nor mountain range1 nor crater ring1 nor gorge1 nor caon1 is able to divert it from its course4 ,it ascends all heights and drops into all depths with perfect indifference1 but its continuity is not broken4 ,when the sun does not illuminate it at a proper angle1 however1 the mysterious ray vanishes4 ,is it a metallic vein1 or is it volcanic lava or ash8 ,was the globe of the moon once split open along this line8 ,the ,mare ,serenitatis is encircled by mountain ranges to a greater extent than any of the other lunar seas4 ,on its eastern side the ,caucasus and the ,apennines shut it in1 except for a strait a hundred miles broad1 by means of which it is connected with the ,mare ,imbrium4 ,on the south the range of the ,hmus ,mountains borders it1 on the north and northwest the ,caucasus and the ,taurus ,mountains confine it1 while on the west1 where again it connects itself by a narrow strait with another sea1 the ,mare ,tranquilitatis1 it encounters the massive uplift of ,mount ,argus4 ,not far from the eastern strait is found the remarkable little crater named ,linn1 not conspicuous on the gray floor of the ,mare1 yet easily enough found1 and very interesting because a considerable change of form seems to have come over this crater some time near the middle of the nineteenth century4 ,in referring to it as a crater it must not be forgotten that it does not form an opening in the top of a mountain4 ,in fact1 the so-called craters on the moon1 generally speaking1 are simply cavities in the lunar surface1 whose bottoms lie deep below the general level1 instead of being elevated on the summit of mountains1 and inclosed in a conical peak4 ,in regard to the alleged change in ,linn1 it has been suggested1 not that a volcanic eruption brought it about1 but that a downfall of steep walls1 or of an unsupported rocky floor1 was the cause4 ,the possibility of such an occurrence1 it must be admitted1 adds to the interest of the observer who regularly studies the moon with a telescope4 ,just on the southern border of the ,mare1 the beautiful ring ,menelaus lies in the center of the chain of the ,hmus ,mountains4 ,the ring is about twenty miles across1 and its central peak is composed of some highly reflecting material1 so that it shines very bright4 ,the streak or ray from ,tycho which crosses the ,mare ,serenitatis passes through the walls of ,menelaus1 and perhaps the central peak is composed of the same substance that forms the ray4 ,something more than a hundred miles east-southeast from ,menelaus1 in the midst of the dark ,mare ,vaporum1 is another brilliant ring mountain which catches the eye1 ,manilius4 ,it exceeds ,menelaus in brightness as well as in size1 its diameter being about twenty-five miles4 ,there is something singular underlying the dark lunar surface here1 for not only is ,manilius extraordinarily brilliant in contrast with the surrounding plain1 but out of that plain1 about forty miles toward the east1 projects a small mountain which is also remarkable for its reflecting properties1 as if the gray ground were underlain by a stratum of some material that flashes back the sunlight wherever it is exposed4 ,the crater mountain1 ,sulpicius ,gallus1 on the border of the ,mare1 north of ,manilius and east of ,menelaus1 is another example of the strange shining quality of certain formations on the moon4 ,follow next the ,hmus range westward until the attention falls upon the great ring mountain ,plinius1 more than thirty miles across1 and bearing an unusual resemblance to a fortification4 ,mr4 ,t4 ,g4 ,elger1 the celebrated ,english selenographer1 says of ,plinius that1 at sunrise1 it reminds one of a great fortress or redoubt erected to command the passage between the ,mare ,tranquilitatis and the ,mare ,serenitatis4 ,but1 of course1 the resemblance is purely fanciful4 ,men1 even though they dwelt in the moon1 would not build a rampart #f1jjj feet high6 ,mount ,argus1 at the southwest corner of the ,mare ,serenitatis1 is a very wonderful object when the sun has just risen upon it4 ,this occurs five days after the new moon4 ,returning to the eastern extremity of the ,mare1 we glance1 in passing1 at the precipitous ,mount ,hadley1 which rises more than #ae1jjj feet above the level of the ,mare and forms the northern point of the ,apennine range4 ,passing into the region of the ,mare ,imbrium1 whose western end is divided into the ,palus ,putredinis on the south and the ,palus ,nebularum on the north1 we notice three conspicuous ring mountains1 ,cassini near the ,alps1 and ,aristillus and ,autolycus1 a beautiful pair1 nearly opposite the strait connecting the two ,maria4 ,cassini is thirty-six miles in diameter1 ,aristillus thirty-four1 and ,autolycus twenty-three4 ,the first named is shallow1 only #d1jjj feet in depth from the highest point of its wall1 while ,aristillus carries some peaks on its girdle #aa1jjj feet high4 ,autolycus1 like ,cassini1 is of no very great depth4 ,westward from the middle of an imaginary line joining ,aristillus and ,cassini is the much smaller crater ,thetetus4 ,outside the walls of this are a number of craterlets1 and a ,french astronomer1 ,charbonneaux1 of the ,meudon ,observatory1 reported in ,december1 #aijj1 that he had repeatedly observed white clouds appearing and disappearing over one of these small craters4 ,south of the ,mare ,vaporum are found some of the most notable of those strange lunar features that are called clefts or rills4 ,two crater mountains1 in particular1 are connected with them1 ,ariadus at the eastern edge of the ,mare ,tranquilitatis and ,hyginus on the southern border of the ,mare ,vaporum4 ,these clefts appear to be broad and deep chasms1 like the caons cut by terrestrial rivers1 but it can not be believed that the lunar caons are the work of rivers4 ,they are rather cracks in the lunar crust1 although their bottoms are frequently visible4 ,the principal cleft from ,ariadus runs eastward and passes between two neighboring craters1 the southern of which is named ,silberschlag1 and is noteworthy for its brightness4 ,the ,hyginus cleft is broader and runs directly through the crater ring of that name4 ,the observer will find much to interest him in the great1 irregular1 and much-broken mountain ring called ,julius ,csar1 as well as in the ring mountains1 ,godin1 ,agrippa1 and ,triesnecker4 ,the last named1 besides presenting magnificent shadows when the sunlight falls aslant upon it1 is the center of a complicated system of rills1 some of which can be traced with our five-inch glass4 ,we next take up ,lunar ,chart ,no4 #b1 and pay a telescopic visit to the southwestern quarter of the lunar world4 ,the ,mare ,tranquilitatis merges through straits into two southern extensions1 the ,mare ,fecunditatis and the ,mare ,nectaris4 ,the great ring mountains or ringed plains1 ,langrenus1 ,vendelinus1 ,petavius1 and ,furnerius1 all lying significantly along the same lunar meridian1 have already been noticed4 ,their linear arrangement and isolated position recall the row of huge volcanic peaks that runs parallel with the shore of the ,pacific ,ocean in ,oregon and ,washington--,mount ,jefferson1 ,mount ,hood1 ,mount ,st4 ,helen's1 ,mount ,tacoma--but these terrestrial volcanoes1 except in elevation1 are mere pins' heads in the comparison4 ,in the eastern part of the ,mare ,fecunditatis lies a pair of relatively small craters named ,messier1 which possess particular interest because it has been suspected1 though not proved1 that a change of form has occurred in one or other of the pair4 ,mdler1 in the first half of the nineteenth century1 represented the two craters as exactly alike in all respects4 ,in #ahee ,webb discovered that they are not alike in shape1 and that the easternmost one is the larger1 and every observer easily sees that ,webb's description is correct4 ,messier is also remarkable for the light streak1 often said to resemble a comet's tail1 which extends from the larger crater eastward to the shore of the ,mare ,fecunditatis4 ,goclenius and ,guttemberg1 on the highland between the ,mare ,fecunditatis and the ,mare ,nectaris1 are intersected and surrounded by clefts1 besides being remarkable for their broken and irregular though lofty walls4 ,guttemberg is forty-five miles and ,goclenius twenty-eight miles in diameter4 ,the short mountain range just east of ,guttemberg1 and bordering a part of the ,mare ,nectaris on the west1 is called the ,pyrenees4 ,the ,mare ,nectaris1 though offering in its appearance no explanation of its toothsome name--perhaps it was regarded as the drinking cup of the ,olympian gods--is one of the most singular of the dark lunar plains in its outlines4 ,at the south it ends in a vast semicircular bay1 sixty miles across1 which is evidently a half-submerged mountain ring4 ,but submerged by what8 ,not water1 but perhaps a sea of lava which has now solidified and forms the floor of the ,mare ,nectaris4 ,the name of this singular formation is ,fracastorius4 ,elger has an interesting remark about it4 ,on the higher portion of the interior1 near the center1 he says1 is a curious object consisting apparently of four light spots1 arranged in a square1 with a craterlet in the middle1 all of which undergo notable changes of aspect under different phases4 ,other writers also call attention to the fine markings1 minute craterlets1 and apparently changeable spots on the floor of ,fracastorius4 ,we go now to the eastern side of the ,mare ,nectaris1 where we find one of the most stupendous formations in the lunar world1 the great mountain ring of ,theophilus1 noticeably regular in outline and perfect in the completeness of its lofty wall4 ,the circular interior1 which contains in the center a group of mountains1 one of whose peaks is #f1jjj feet high1 sinks #aj1jjj feet below the general level of the moon outside the wall6 ,one of the peaks on the western edge towers more than #ah1jjj feet above the floor within1 while several other peaks attain elevations of #ae1jjj to #af1jjj feet4 ,the diameter of the immense ring1 from crest to crest of the wall1 is sixty-four miles4 ,theophilus is especially wonderful on the fifth and sixth days of the moon1 when the sun climbs its shining pinnacles and slowly discloses the tremendous chasm that lies within its circles of terrible precipices4 ,on the southeast ,theophilus is connected by extensions of its walls with a shattered ring of vast extent called ,cyrillus2 and south from ,cyrillus1 and connected with the same system of broken walls1 lies the still larger ring named ,catharina1 whose half-ruined walls and numerous crater pits present a fascinating spectacle as the shadows retreat before the sunrise advancing across them4 ,these three--,theophilus1 ,cyrillus1 and ,catharina--constitute a scene of surpassing magnificence1 a glimpse of wonders in another world sufficient to satisfy the most riotous imagination4 ,south of the ,mare ,nectaris the huge ring mountain of ,piccolomini attracts attention1 its massive walls surrounding a floor nearly sixty miles across1 and rising in some places to an altitude of nearly #ae1jjj feet4 ,it should be understood that wherever the height of the mountain wall of such a ring is mentioned1 the reference level is that of the interior plain or floor4 ,the elevation1 reckoned from the outer side1 is always very much less4 ,the entire region south and east of ,theophilus and its great neighbors is marvelously rough and broken4 ,approaching the center of the moon1 we find a system of ringed plains even greater in area than any of those we have yet seen4 ,hipparchus is nearly a hundred miles long from north to south1 and nearly ninety miles broad from east to west4 ,but its walls have been destroyed to such an extent that1 after all1 it yields in grandeur to a formation like ,theophilus4 ,albategnius is sixty-five miles across1 with peaks from #aj1jjj to #ae1jjj feet in height4 ,sacrobosco is a confused mass of broken and distorted walls4 ,aliacensis is remarkable for having a peak on the eastern side of its wall which is more than #af1jjj feet high4 ,werner1 forty-five miles in diameter1 is interesting because under its northeastern wall ,mdler1 some seventy years ago1 saw a light spot of astonishing brightness1 unmatched in that respect by anything on the moon except the peak of ,aristarchus1 which we shall see later4 ,this spot seems afterward to have lost brilliance1 and the startling suggestion has been made that its original brightness might have been due to its then recent deposit from a little crater that lies in the midst of it4 ,walter is of gigantic dimensions1 about one hundred miles in diameter4 ,unlike the majority of the ringed plains1 it departs widely from a circle4 ,stfler is yet larger than ,walter2 but most interesting of all these gigantic formations is ,maurolycus1 whose diameter exceeds one hundred and fifty miles1 and which has walls #ac1jjj or #ad1jjj feet high4 ,yet1 astonishing though it may seem1 this vast and complicated mass of mountain walls1 craters1 and peaks1 is virtually unseen at full moon1 owing to the perpendicularity of the sunlight1 which prevents the casting of shadows4 ,we shall next suppose that another period of about seven days has elapsed1 the moon in the meantime reaching its full phase4 ,we refer for guidance to ,lunar ,chart ,no4 #c4 ,the peculiarity of the northeastern quadrant which immediately strikes the eye is the prevalence of the broad plains called ,maria1 or seas4 ,the northern and central parts are occupied by the ,mare ,imbrium1 the ,sea of ,showers or of ,rains1 with its dark bay the ,sinus stuum1 while the eastern half is covered by the vast ,oceanus ,procellarum1 the ,ocean of ,storms or of ,tempests4 ,toward the north a conspicuous oval1 remarkably dark in hue1 immediately attracts our attention4 ,it is the celebrated ringed plain of ,plato1 about sixty miles in diameter and surrounded by a saw-edged rampart1 some of whose pinnacles are #f1jjj or #g1jjj feet high4 ,plato is a favorite subject for study by selenographers because of the changes of color which its broad1 flat floor undergoes as the sun rises upon it1 and also because of the existence of enigmatical spots and streaks whose visibility changes4 ,south of ,plato1 in the ,mare ,imbrium1 rises a precipitous1 isolated peak called ,pico1 #h1jjj feet in height4 ,its resemblance in situation to the conical mountain ,pico in the ,azores strikes the observer4 ,illustration3 ,,lunar ,,chart ,,no4 #c1 ,,northeast ,,quarter4 ,eastward of ,plato a line of highlands1 separating the ,mare ,imbrium from the ,mare ,frigoris1 carries the eye to the beautiful semicircular ,sinus ,iridum1 or ,bay of ,rainbows4 ,the northwestern extremity of this remarkable bay is guarded by a steep and lofty promontory called ,cape ,laplace1 while the southeastern extremity also has its towering guardian1 ,cape ,heraclides4 ,the latter is interesting for showing1 between nine and ten days after full moon1 a singularly perfect profile of a woman's face looking out across the ,mare ,imbrium4 ,the winding lines1 like submerged ridges1 delicately marking the floor of the ,sinus ,iridum and that of the ,mare beyond1 are beautiful telescopic objects4 ,the bay is about one hundred and thirty-five miles long by eighty-four broad4 ,the ,mare ,imbrium1 covering #cdj1jjj square miles1 is sparingly dotted over with craters4 ,all of the more conspicuous of them are indicated in the chart4 ,the smaller ones1 like ,caroline ,herschel1 ,helicon1 ,leverrier1 ,dlisle1 etc41 vary from eight to twelve miles in diameter4 ,lambert is seventeen miles in diameter1 and ,euler nineteen1 while ,timocharis is twenty-three miles broad and #g1jjj feet deep below its walls1 which rise only #c1jjj feet above the surface of the ,mare4 ,toward the eastern border of the sea1 south of the ,harbinger ,mountains1 we find a most remarkable object1 the mountain ring1 or crater plain1 called ,aristarchus4 ,this ring is not quite thirty miles in diameter1 but there is nothing on the moon that can compare with it in dazzling brilliance4 ,the central peak1 #a1bjj or #a1cjj feet high1 gleams like a mountain of crusted snow1 or as if it were composed of a mass of fresh-broken white metal1 or of compacted crystals4 ,part of the inner slope of the east wall is equally brilliant4 ,in fact1 so much light is poured out of the circumvallation that the eye is partially blinded1 and unable distinctly to see the details of the interior4 ,no satisfactory explanation of the extraordinary reflecting power of ,aristarchus has ever been offered4 ,its neighbor toward the east1 ,herodotus1 is somewhat smaller and not remarkably bright1 but it derives great interest from the fact that out of a breach in its northern wall issues a vast cleft1 or chasm1 which winds away for nearly a hundred miles across the floor of the ,mare1 making an abrupt turn when it reaches the foot of the ,harbinger ,mountains4 ,the comparatively small crater1 ,lichtenberg1 near the northeastern limb of the moon1 is interesting because ,mdler used to see in its neighborhood a pale-red tint which has not been noticed since his day4 ,returning to the western side of the quadrant represented in ,lunar ,chart ,no4 #c1 we see the broad and beautifully regular ringed plain of ,archimedes1 fifty miles in diameter and #d1jjj feet deep4 ,a number of clefts extend between the mountainous neighborhood of ,archimedes and the feet of the gigantic ,apennine ,mountains on the southwest4 ,the little double crater1 ,beer1 between ,archimedes and ,timocharis1 is very bright4 ,the ,apennines extend about four hundred and eighty miles in a northwesterly and southeasterly direction4 ,one of their peaks near the southern end of the range1 ,mount ,huygens1 is at least #ah1jjj feet high1 and the black silhouettes of their sharp-pointed shadows thrown upon the smooth floor of the ,mare ,imbrium about the time of first quarter present a spectacle as beautiful as it is unique4 ,the ,apennines end at the southeast in the ring mountain1 ,eratosthenes1 thirty-eight miles across and very deep1 one of its encircling chain of peaks rising #af1jjj feet above the floor1 and about half that height above the level of the ,mare ,imbrium4 ,the shadows cast by ,eratosthenes at sunrise are magnificent4 ,and now we come to one of the supreme spectacles of the moon1 the immense ring or crater mountain ,copernicus4 ,this is generally regarded as the grandest object that the telescope reveals on the earth's satellite4 ,it is about fifty-six miles across1 and its interior falls to a depth of #h1jjj feet below the ,mare ,imbrium4 ,its broad wall1 composed of circle within circle of ridges1 terraces1 and precipices1 rises on the east about #ab1jjj feet above the floor4 ,on the inner side the slopes are very steep1 cliff falling below cliff1 until the bottom of the fearful abyss is attained4 ,to descend those precipices and reach the depressed floor of ,copernicus would be a memorable feat for a mountaineer4 ,in the center of the floor rises a complicated mountain mass about #b1djj feet high4 ,all around ,copernicus the surface of the moon is dotted with countless little crater pits1 and splashed with whitish streaks4 ,northward lie the ,carpathian ,mountains1 terminating on the east in ,tobias ,mayer1 a ring mountain more than twenty miles across4 ,the mountain ring ,kepler1 which is also the center of a great system of whitish streaks and splashes1 is twenty-two miles in diameter1 and notably brilliant4 ,finally1 we turn to the southeastern quadrant of the moon1 represented in ,lunar ,chart ,no4 #d4 ,the broad1 dark expanse extending from the north is the ,mare ,nubium on the west and the ,oceanus ,procellarum on the east4 ,toward the southeast appears the notably dark1 rounded area of the ,mare ,humorum inclosed by highlands and rings4 ,we begin with the range of vast inclosures running southward near the central meridian1 and starting with ,ptolemus1 a walled plain one hundred and fifteen miles in its greatest diameter and covering an area considerably exceeding that of the ,state of ,massachusetts4 ,its neighbor toward the south1 ,alphonsus1 is eighty-three miles across4 ,next comes ,arzachel1 more than sixty-five miles in diameter4 ,thebit1 more than thirty miles across1 is very deep4 ,east of ,thebit lies the celebrated lunar railroad1 a straight1 isolated wall about five hundred feet high and sixty-five miles long1 dividing at its southern end into a number of curious branches1 forming the buttresses of a low mountain4 ,purbach is sixty miles broad1 and south of that comes a wonderful region where the ring mountains ,hell1 ,ball1 ,lexell1 and others1 more or less connected with walls1 inclose an area even larger than ,ptolemus1 but which1 not being so distinctly bordered as some of the other inclosed plains1 bears no distinctive name4 ,illustration3 ,,lunar ,,chart ,,no4 #d1 ,,southeast ,,quarter4 ,the next conspicuous object toward the south ranks with ,copernicus among the grandest of all lunar phenomena--the ring1 or crater1 ,tycho4 ,it is about fifty-four miles in diameter and some points on its wall rise #ag1jjj feet above the interior4 ,in the center is a bright mountain peak #e1jjj feet high4 ,but wonderful as are the details of its mountain ring1 the chief attraction of ,tycho is its manifest relation to the mysterious bright rays heretofore referred to1 which extend far across the surface of the moon in all directions1 and of which it is the center4 ,the streaks about ,copernicus are short and confused1 constituting rather a splash than a regular system of rays2 but those emanating from ,tycho are very long1 regular1 comparatively narrow1 and form arcs of great circles which stretch away for hundreds of miles1 allowing no obstacle to interrupt their course4 ,southwest of ,tycho lies the vast ringed plain of ,maginus1 a hundred miles broad and very wonderful to look upon1 with its labyrinth of formations1 when the sun slopes across it1 and yet1 like ,maurolycus1 invisible under a vertical illumination4 ,the full moon1 to use ,mdler's picturesque expression1 knows no ,maginus4 ,still larger and yet more splendid is ,clavius1 which exceeds one hundred and forty miles in diameter and covers #af1jjj square miles of ground within its fringing walls1 which carry some of the loftiest peaks on the moon1 several attaining #ag1jjj feet4 ,the floor is deeply depressed1 so that an inhabitant of this singular inclosure1 larger than ,massachusetts1 ,connecticut1 and ,rhode ,island combined1 would dwell in land sunk two miles below the general level of the world about him4 ,in the neighborhood of the south pole lies the large walled plain of ,newton1 whose interior is the deepest known depression on the moon4 ,it is so deep that the sunshine never touches the larger part of the floor of the inner abyss1 and a peak on its eastern wall rises #bd1jjj feet sheer above the tremendous pit4 ,other enormous walled plains are ,longomontanus1 ,wilhelm ,i1 ,schiller1 ,bailly1 and ,schickard4 ,the latter is one hundred and thirty-four miles long and bordered by a ring varying from #d1jjj to #i1jjj feet in height4 ,wargentin1 the oval close to the moon's southeast limb1 beyond ,schickard1 is a unique formation in that1 instead of its interior being sunk below the general level1 it is elevated above it4 ,it has been suggested that this peculiarity is due to the fact that the floor of ,wargentin was formed by inflation from below1 and that it has cooled and solidified in the shape of a gigantic dome arched over an immense cavity beneath4 ,a dome of such dimensions1 however1 could not retain its form unless partly supported from beneath4 ,hainzel is interesting from its curious outline2 ,cichus for the huge yawning crater on its eastern wall2 ,capuanus for a brilliant shining crater also on its eastern wall2 and ,mercator for possessing bright craters on both its east and its west walls4 ,vitello has a bright central mountain and gains conspicuousness from its position at the edge of the dark ,mare ,humorum4 ,agatharchides is the broken remnant of a great ring mountain4 ,gassendi1 an extremely beautiful object1 is about fifty-five miles across4 ,it is encircled with broken walls1 craters and bright points1 and altogether presents a very splendid appearance about the eleventh day of the moon's age4 ,letronne is a half-submerged ring1 at the southern end of the ,oceanus ,procellarum1 which recalls ,fracastorius in the western lunar hemisphere4 ,it lies1 however1 ten degrees nearer the equator than ,fracastorius4 ,billy is a mountain ring whose interior seems to have been submerged by the dark substance of the ,oceanus ,procellarum1 although its walls have remained intact4 ,mersenius is a very conspicuous ring1 forty miles in diameter1 east of the ,mare ,humorum4 ,vieta1 fifty miles across1 is also a fine object4 ,grimaldi1 a huge dusky oval1 is nearly one hundred and fifty miles in its greatest length4 ,the ring mountain ,landsberg1 on the equator1 and near the center of the visible eastern hemisphere1 is worth watching because ,elger noticed changes of color in its interior in #ahhh4 ,bullialdus1 in the midst of the ,mare ,nubium1 is a very conspicuous and beautiful ring mountain about thirty-eight miles in diameter1 with walls #h1jjj feet high above the interior4 ,those who wish to see the lunar mountains in all their varying aspects will not content themselves with views obtained during the advance of the sunlight from west to east1 between new moon and full moon1 but will continue their observations during the retreat of the sunlight from east to west1 after the full phase is passed4 ,it is evident that the hemisphere of the moon which is forever turned away from the earth is quite as marvelous in its features as the part that we see4 ,it will be noticed that the entire circle of the moon's limb1 with insignificant interruptions1 is mountainous4 ,possibly the invisible side of our satellite contains yet grander peaks and crater mountains than any that our telescopes can reach4 ,this probability is increased by the fact that the loftiest known mountain on the moon is never seen except in silhouette4 ,it is a member of a great chain that breaks the lunar limb west of the south pole1 and that is called the ,leibnitz ,mountains4 ,the particular peak referred to is said by some authorities to exceed #cj1jjj feet in height4 ,other great ranges seen only in profile are the ,drfel ,mountains on the limb behind the ring plain ,bailly1 the ,cordilleras1 east of ,eichstadt1 and the ,d',alembert ,mountains beyond ,grimaldi4 ,the profile of these great mountains is particularly fine when they are seen during an eclipse of the sun4 ,then1 with the disk of the sun for a background1 they stand out with startling distinctness4 ,,the ,,sun ,when the sun is covered with spots it becomes a most interesting object for telescopic study4 ,every amateur's telescope should be provided with apparatus for viewing the sun4 ,a dark shade glass is not sufficient and not safe4 ,what is known as a solar prism1 consisting of two solid prisms of glass1 cemented together in a brass box which carries a short tube for the eyepiece1 and reflecting an image of the sun from their plane of junction--while the major remnant of light and heat passes directly through them and escapes from an opening provided for the purpose--serves very well4 ,better and more costly is an apparatus called a helioscope1 constructed on the principle of polarization and provided with prisms and reflectors which enable the observer1 by proper adjustment1 to govern very exactly and delicately the amount of light that passes into the eyepiece4 ,furnished with an apparatus of this description we can employ either a three-1 four-1 or five-inch glass upon the sun with much satisfaction4 ,for the amateur's purposes the sun is only specially interesting when it is spotted4 ,the first years of the twentieth century will behold a gradual growth in the number and size of the solar spots as those years happen to coincide with the increasing phase of the sun-spot period4 ,large sun spots and groups of spots often present an immense amount of detail which tasks the skill of the draughtsman to represent it4 ,but a little practice will enable one to produce very good representations of sun spots1 as well as of the whitish patches called facul by which they are frequently surrounded4 ,for the simple purpose of exhibiting the spotted face of the sun without much magnifying power1 a telescope may be used to project the solar image on a white sheet or screen4 ,if the experiment is tried in a room1 a little ingenuity will enable the observer to arrange a curtain covering the window used1 in such a way as to exclude all the light except that which comes through the telescope4 ,then1 by placing a sheet of paper or a drawing board before the eyepiece and focusing the image of the sun upon it1 very good results may be obtained4 ,if one has a permanent mounting and a driving clock1 a small spectroscope may be attached1 for solar observations1 even to a telescope of only four or five inches aperture1 and with its aid most interesting views may be obtained of the wonderful red hydrogen flames that frequently appear at the edge of the solar disk4 ,,chapter ,x ,,are ,,there ,,planets ,,among ,,the ,,stars8 444 ,and if there should be ,worlds greater than thine own1 inhabited ,by greater things1 and they themselves far more ,in number than the dust of thy dull earth1 ,what wouldst thou think8--,,byron',s ,,cain4 ,this always interesting question has lately been revived in a startling manner by discoveries that have seemed to reach almost deep enough to touch its solution4 ,the following sentences1 from the pen of ,dr4 ,t4 ,j4 ,j4 ,see1 of the ,lowell ,observatory1 are very significant from this point of view3 ,our observations during #ahif-'ig have certainly disclosed stars more difficult than any which astronomers had seen before4 ,among these obscure objects about half a dozen are truly wonderful1 in that they seem to be dark1 almost black in color1 and apparently are shining by a dull reflected light4 ,it is unlikely that they will prove to be self-luminous4 ,if they should turn out dark bodies in fact1 shining only by the reflected light of the stars around which they revolve1 we should have the first case of planets--dark bodies--noticed among the fixed stars4 ,of course1 ,dr4 ,see has no reference in this statement to the immense dark bodies which1 in recent years1 have been discovered by spectroscopic methods revolving around some of the visible stars1 although invisible themselves4 ,the obscure objects that he describes belong to a different class1 and might be likened1 except perhaps in magnitude1 to the companion of ,sirius1 which1 though a light-giving body1 exhibits nevertheless a singular defect of luminosity in relation to its mass4 ,sirius has only twice the mass1 but ten thousand times the luminosity1 of its strange companion6 ,yet the latter is evidently rather a faint1 or partially extinguished1 sun than an opaque body shining only with light borrowed from its dazzling neighbor4 ,the objects seen by ,dr4 ,see1 on the contrary1 are apparently shining by a dull reflected light4 ,if1 however 7as he evidently thinks is probable71 these objects should prove to be really non-luminous1 it would not follow that they are to be regarded as more like the planets of the solar system than like the dark companions of certain other stars4 ,a planet1 in the sense which we attach to the word1 can not be comparable in mass and size with the sun around which it revolves4 ,the sun is a thousand times larger than the greatest of its attendant planets1 ,jupiter1 and more than a million times larger than the earth4 ,it is extremely doubtful whether the relation of sun and planet could exist between two bodies of anything like equal size1 or even if one exceeded the other many times in magnitude4 ,it is only when the difference is so great that the smaller of the two bodies is insignificant in comparison with the larger1 that the former could become a cool1 life-bearing globe1 nourished by the beneficent rays of its organic comrade and master4 ,judged by our terrestrial experience1 which is all we have to go by1 the magnitude of a planet1 if it is to bear life resembling that of the earth1 is limited by other considerations4 ,even ,jupiter1 which1 as far as our knowledge extends1 represents the extreme limit of great planetary size1 may be too large ever to become the abode of living beings of a high organization4 ,the force of gravitation on the surface of ,jupiter exceeds that on the earth's surface as #b4fd to #a4 ,considering the effects of this on the weight and motion of bodies1 the density of the atmosphere1 etc41 it is evident that ,jupiter would1 to say the very least1 be an exceedingly uncomfortable place of abode for beings resembling ourselves4 ,but ,jupiter1 if it is ever to become a solid1 rocky globe like ours1 must shrink enormously in volume1 since its density is only #j4bd as compared with the earth4 ,now1 the surface gravity of a planet depends on its mass and its radius1 being directly as the former and inversely as the square of the latter4 ,but in shrinking ,jupiter will lose none of its mass1 although its radius will become much smaller4 ,the force of gravity will consequently increase on its surface as the planet gets smaller and more dense4 ,the present mean diameter of ,jupiter is #hf1ejj miles1 while its mass exceeds that of the earth in the ratio of #caf to #a4 ,suppose ,jupiter shrunk to three quarters of its present diameter1 or #fd1hjj miles1 then its surface gravity would exceed the earth's nearly five times4 ,with one half its present diameter the surface gravity would become more than ten times that of the earth4 ,on such a planet a man's bones would snap beneath his weight1 even granting that he could remain upright at all6 ,it would seem1 then1 that1 unless we are to abandon terrestrial analogies altogether and go it blind1 we must set an upper limit to the magnitude of a habitable planet1 and that ,jupiter represents such upper limit1 if1 indeed1 he does not transcend it4 ,the question then becomes1 ,can the faint objects seen by ,dr4 ,see and his fellow-observers1 in the near neighborhood of certain stars1 be planets in the sense just described1 or are they necessarily far greater in magnitude than the largest planet1 in the accepted sense of that word1 which can be admitted into the category--viz41 the planet ,jupiter8 ,this resolves itself into another question3 ,at what distance would ,jupiter be visible with a powerful telescope1 supposing it to receive from a neighboring star an amount of illumination not less than that which it gets from the sun8 ,to be sure1 we do not know how far away the faint objects described by ,dr4 ,see are2 but1 at any rate1 we can safely assume that they are at the distance of the nearest stars1 say somewhere about three hundred thousand times the earth's distance from the sun4 ,the sun itself removed to that distance would appear to our eyes only as a star of the first magnitude4 ,but ,zllner has shown that the sun exceeds ,jupiter in brilliancy #e1dgb1jjj1jjj times4 ,seen from equal distances1 however1 the ratio would be about #bah1jjj1jjj to #a4 ,this would be the ratio of their light if both sun and ,jupiter could be removed to about the distance of the nearest stars4 ,since the sun would then be only as bright as one of the stars of the first magnitude1 and since ,jupiter would be #bah1jjj1jjj times less brilliant1 it is evident that the latter would not be visible at all4 ,the faintest stars that the most powerful telescopes are able to show probably do not fall below the sixteenth or1 at the most1 the seventeenth magnitude4 ,but a seventeenth-magnitude star is only between two and three million times fainter than the sun would appear at the distance above supposed1 while1 as we have seen1 ,jupiter would be more than two hundred million times fainter than the sun4 ,to put it in another way3 ,jupiter1 at the distance of the nearest stars1 would be not far from one hundred times less bright than the faintest star which the largest telescope is just able1 under the most exquisite conditions1 to glimpse4 ,to see a star so faint as that would require an object-glass of a diameter half as great as the length of the tube of the ,lick telescope1 or say thirty feet6 ,of course1 ,jupiter might be more brilliantly illuminated by a brighter star than the sun2 but1 granting that1 it still would not be visible at such a distance1 even if we neglect the well-known concealing or blinding effect of the rays of a bright star when the observer is trying to view a faint one close to it4 ,clearly1 then1 the obscure objects seen by ,dr4 ,see near some of the stars1 if they really are bodies visible only by light reflected from their surfaces1 must be enormously larger than the planet ,jupiter1 and can not1 accordingly1 be admitted into the category of planets proper1 whatever else they may be4 ,perhaps they are extreme cases of what we see in the system of ,sirius--i4e41 a brilliant star with a companion which has ceased to shine as a star while retaining its bulk4 ,such bodies may be called planets in that they only shine by reflected light1 and that they are attached to a brilliant sun2 but the part that they play in their systems is not strictly planetary4 ,owing to their great mass they bear such sway over their shining companions as none of our planets1 nor all of them combined1 can exercise2 and for the same reason they can not1 except in a dream1 be imagined to possess that which1 in our eyes1 must always be the capital feature of a planet1 rendering it in the highest degree interesting wherever it may be found--sentient life4 ,it does not follow1 however1 that there are no real planetary bodies revolving around the stars4 ,as ,dr4 ,see himself remarks1 such insignificant bodies as our planets could not be seen at the distance of the fixed stars1 even if the power of our telescopes were increased a hundredfold1 and consequently no such systems are known4 ,this brings me to another branch of the subject4 ,in the same article from which ,i have already quoted 7,recent ,discoveries respecting the ,origin of the ,universe1 ,atlantic ,monthly1 vol4 lxxx1 pages #dhd-dib71 ,dr4 ,see sets forth the main results of his well-known studies on the origin of the double and multiple star systems4 ,he finds that the stellar systems differ from the solar system markedly in two respects1 which he thus describes3 #a4 ,the orbits are highly eccentric2 on the average twelve times more elongated than those of the planets and satellites4 #b4 ,the components of the stellar systems are frequently equal and always comparable in mass1 whereas our satellites are insignificant compared to their planets1 and the planets are equally small compared to the sun4 ,these peculiarities of the star systems ,dr4 ,see ascribes to the effect of tidal friction1 the double stars having had their birth through fission of original fluid masses 7just as the moon1 according to ,george ,darwin's theory1 was born from the earth71 and the reaction of tidal friction having not only driven them gradually farther apart but rendered their orbits more and more eccentric4 ,this manner of evolution of a stellar system ,dr4 ,see contrasts with ,laplace's hypothesis of the origin of the planetary system through the successive separation of rings from the periphery of the contracting solar nebula1 and the gradual breaking up of those rings and their aggregation into spherical masses or planets4 ,while not denying that the process imagined by ,laplace may have taken place in our system1 he discovers no evidence of its occurrence among the double stars1 and this leads him to the following statement1 in which believers in the old theological doctrine that the earth is the sole center of mortal life and of divine care would have found much comfort3 ,it is very singular that no visible system yet discerned has any resemblance to the orderly and beautiful system in which we live2 and one is thus led to think that probably our system is unique in its character4 ,at least it is unique among all known systems4 ,if we grant that the solar system is the only one in which small planets exist revolving around their sun in nearly circular orbits1 then indeed we seem to have closed all the outer universe against such beings as the inhabitants of the earth4 ,beyond the sun's domain only whirling stars1 coupled in eccentric orbits1 dark stars1 some of them1 but no planets--in short a wilderness1 full of all energies except those of sentient life6 ,this is not a pleasing picture1 and ,i do not think we are driven to contemplate it4 ,beyond doubt1 ,dr4 ,see is right in concluding that double and multiple star systems1 with their components all of magnitudes comparable among themselves1 revolving in exceedingly eccentric orbits under the stress of mutual gravitation1 bear no resemblance to the orderly system of our sun with its attendant worlds4 ,and it is not easy to imagine that the respective members of such systems could themselves be the centers of minor systems of planets1 on account of the perturbing influences to which the orbits of such minor systems would be subjected4 ,but the double and multiple stars1 numerous though they be1 are outnumbered a hundred to one by the single stars which shine alone as our sun does4 ,what reason can we have1 then1 for excluding these single stars1 constituting as they do the vast majority of the celestial host1 from a similarity to the sun in respect to the manner of their evolution from the original nebulous condition8 ,these stars exhibit no companions1 such planetary attendants as they may have lying1 on account of their minuteness1 far beyond the reach of our most powerful instruments4 ,but since they vastly outnumber the binary and multiple systems1 and since they resemble the sun in having no large attendants1 should we be justified1 after all1 in regarding our system as unique8 ,it is true we do not know1 by visual evidence1 that the single stars have planets1 but we find planets attending the only representative of that class of stars that we are able to approach closely--the sun--and we know that the existence of those planets is no mere accident1 but the result of the operation of physical laws which must hold good in every instance of nebular condensation4 ,two different methods are presented in which a rotating and contracting nebula may shape itself into a stellar or planetary system4 ,the first is that described by ,laplace1 and generally accepted as the probable manner of origin of the solar system--viz41 the separation of rings from the condensing mass1 and the subsequent transformation of the rings into planets4 ,the planet ,saturn is frequently referred to as an instance of the operation of this law1 in which the evolution has been arrested after the separation of the rings1 the latter having retained the ring form instead of breaking and collecting into globes1 forming in this case rings of meteorites1 and reminding us of the comparatively scattered rings of asteroids surrounding the sun between the orbits of ,mars and ,jupiter4 ,this ,laplacean process ,dr4 ,see regards as theoretically possible1 but apparently he thinks that if it took place it was confined to our system4 ,the other method is that of the separation of the original rotating mass into two nearly equal parts4 ,the mechanical possibility of such a process has been proved1 mathematically1 by ,poincar and ,darwin4 ,this1 ,dr4 ,see thinks1 is the method which has prevailed among the stars1 and prevailed to such a degree as to make the solar system1 formed by the ring method1 probably a unique phenomenon in the universe4 ,is it not more probable that both methods have been in operation1 and that1 in fact1 the ring method has operated more frequently than the other8 ,if not1 why do the single stars so enormously outnumber the double ones8 ,it is of the essence of the fission process that the resulting masses should be comparable in size4 ,if1 then1 that process has prevailed in the stellar universe to the practical exclusion of the other1 there should be very few single stars2 whereas1 as a matter of fact1 the immense majority of the stars are single4 ,and1 remembering that the sun viewed from stellar distances would appear unattended by subsidiary bodies1 are we not justified in concluding that its origin is a type of the origin of the other single stars8 ,while it is1 as ,i have remarked1 of the essence of the fission process that the resulting parts of the divided mass should be comparable in magnitude1 it is equally of the essence of the ring1 or ,laplacean process1 that the bodies separated from the original mass should be comparatively insignificant in magnitude4 ,as to the coexistence of the two processes1 we have1 perhaps1 an example in the solar system itself4 ,darwin's demonstration of the possible birth of the moon from the earth1 through fission and tidal friction1 does not apply to the satellites attending the other planets4 ,the moon is relatively a large body1 comparable in that respect with the earth1 while the satellites of ,jupiter and ,saturn1 for instance1 are relatively small4 ,but in the case of ,saturn there is visible evidence that the ring process of satellite formation has prevailed4 ,the existing rings have not broken up1 but their very existence is a testimony of the origin of the satellites exterior to them from other rings which did break up4 ,thus we need not go as far away as the stars in order to find instances illustrating both the methods of nebular evolution that we have been dealing with4 ,the conclusion1 then1 seems to be that we are not justified in assuming that the solar system is unique simply because it differs widely from the double and multiple star systems2 and that we should rather regard it as probable that the vast multitude of stars which do not appear1 when viewed with the telescope1 or studied by spectroscopic methods1 to have any attendants comparable with themselves in magnitude1 have originated in a manner resembling that of the sun's origin1 and may be the centers of true planetary systems like ours4 ,the argument1 ,i think1 goes further than to show the mere possibility of the existence of such planetary systems surrounding the single stars4 ,if those stars did not originate in a manner quite unlike the origin of the sun1 then the existence of planets in their neighborhood is almost a foregone conclusion1 for the sun could hardly have passed through the process of formation out of a rotating nebula without evolving planets during its contraction4 ,and so1 notwithstanding the eccentricities of the double stars1 we may still cherish the belief that there are eyes to see and minds to think out in celestial space4 ,,index ,,note4--,double1 triple1 multiple1 and colored stars1 star clusters1 nebul1 and temporary stars will be found arranged under the heads of their respective constellations4 ,,andromeda1 ,map ,no4 #bd1 #abe4 ,stars3 alpha1 #abf4 gamma1 #abh4 1 #abf4 #cf1 #abh4 ,temporary star3 #ahhe1 #abg4 ,cluster3 #deg1 #abh4 ,variable3 ,r1 #abh4 ,nebula3 #aaf1 #abf4 ,,aquarius1 ,map ,no4 #ah1 #ajg4 ,stars3 zeta1 #ajf4 tau1 #ajh4 psi1 #ajh4 #da1 #ajf4 ,sigma #bgbi1 #ajf4 ,sigma #bgde 7#ab71 #ajf4 ,sigma #biih1 #ajh4 ,variables3 ,r1 #ajh4 ,s1 #ajh4 ,t1 #ajf4 ,nebul3 #dfbh 7,rosse's ,saturn71 #ajh4 #dfgh1 #ajh4 ,,aquila1 ,map ,no4 #af1 #ie4 ,stars3 pi1 #id4 #aa1 #id4 #bc1 #id4 #eg1 #id4 ,sigma #bfdd1 #id4 ,sigma #bedd1 #id4 ,cluster3 #dddj1 #id4 ,variables3 eta1 #id4 ,r1 #id4 ,,argo3 ,map ,no4 #b1 #ca2 ,map ,no4 #g1 #ee4 ,stars3 ,sigma #ajig1 #cc4 ,sigma #aadf 7#e71 #ce4 ,clusters3 #aeea1 #ce4 #aefd1 #ce4 #aega1 #ce4 #afcj1 #ef4 ,nebula3 #aefd1 #ce4 ,,aries1 ,map ,no4 #bb1 #aai4 ,stars3 gamma1 #aah4 epsilon1 #abj4 lambda1 #aah4 pi1 #aah4 #ad1 #aah4 #cj1 #aah4 #da1 #aah4 #eb1 #abj4 ,sigma #bhi1 #aah4 ,,auriga1 ,map ,no4 #e1 #de4 ,stars3 alpha 7,capella71 #dd4 beta 7,menkalina71 #df4 epsilon1 #ej4 theta1 #dh4 lambda1 #ej4 #ad1 #ej4 #bf1 #ej4 #da1 #ea4 ,sigma #faf1 #dh4 ,temporary star3 #ahib1 #dh4 ,clusters3 #iif1 #ea4 #ajfg1 #ea4 #aaai1 #ea4 #aaff1 #ea4 #abie1 #dh4 ,,bo,,tes1 ,map ,no4 #aa1 #fg4 ,stars3 alpha 7,arcturus71 #ff4 delta1 #ga4 epsilon 7,mirac71 #ga4 zeta1 #gj4 iota1 #ga4 kappa1 #ga4 1 #ga4 xi1 #gj4 pi1 #gj4 ,sigma #aggb1 #gj4 ,sigma #ahij 7#ci71 #ga4 ,sigma #aiji 7#dd71 #ga4 ,sigma #aiaj 7#bgi71 #gj4 ,sigma #aibf1 #ga4 ,,camelopardalus1 ,map ,no4 #be1 #acc4 ,stars3 #a1 #acd4 #b1 #acd4 #g1 #ace4 ,sigma #che1 #acd4 ,sigma #cij1 #acd4 ,cluster3 #idj1 #ace4 ,,canes ,,venatici1 ,map ,no4 #bf1 #acg2 ,map ,no4 #aa1 #fg4 ,stars3 #b1 #acf4 #ab 7,cor ,caroli71 #acf4 ,sigma #afjf1 #acf4 ,sigma #agfh 7#be71 #gb4 ,cluster3 #cicf1 #gb4 ,nebula3 #cegb1 #acf4 ,,canis ,,major1 ,map ,no4 #b1 #ca4 ,stars3 alpha 7,sirius71 #cj4 delta1 #cc4 1 #cc4 ,clusters3 #aded1 #cc4 #adgi1 #cc4 #aeab1 #cc4 ,variable3 gamma1 #cc4 ,nebula3 #aeaa1 #cc4 ,,canis ,,minor1 ,map ,no4 #c1 #cd4 ,stars3 alpha 7,procyon71 #cf4 #ad1 #cf4 ,sigma #aabf 7#ca ,can4 ,min4 ,bode71 #cf4 ,,cancer1 ,map ,no4 #d1 #ci4 ,stars3 zeta1 #dc4 iota1 #dd4 #ff1 #dd4 ,sigma #abbc1 #dd4 ,sigma #abia1 #dd4 ,sigma #acaa1 #dd4 ,clusters3 ,prsepe1 #dc4 #agab1 #dd4 ,,capricornus1 ,map ,no4 #ac1 #hc2 ,map ,no4 #ah1 #ajg4 ,stars3 alpha1 #hd4 beta1 #he4 omicron1 #he4 pi1 #he4 rho1 #he4 sigma1 #he4 ,cluster3 #dfjh1 #he4 ,,cassiopeia1 ,map ,no4 #be1 #acc4 ,stars3 eta1 #acb4 iota1 #acb4 sigma1 #acb4 psi1 #acb4 ,temporary star3 #aegb 7,tycho's71 #acd4 ,cluster3 #cib1 #acd4 ,,cepheus1 ,map ,no4 #be1 #acc4 ,,cetus1 ,map ,no4 #bj1 #aab4 ,stars3 alpha1 #aah4 gamma1 #aac4 zeta1 #aaa4 eta1 #aaa4 #bf1 #aaa4 #db1 #aaa4 ,variables3 omicron 7,mira71 #aaa4 ,r1 #aac4 ,s1 #aac4 ,,columba1 ,map ,no4 #b1 #ca4 ,,coma ,,berenices1 ,map ,no4 #f1 #ec4 ,stars3 #b1 #ed4 #ab1 #ed4 #ag1 #ed4 #bd1 #ed4 #ce1 #ed4 #db1 #ed4 ,clusters3 #bgeb1 #ef4 #cdec1 #ef4 ,,corona ,,borealis1 ,map ,no4 #aa1 #fg4 ,stars3 gamma1 #gb4 zeta1 #gc4 eta1 #gb4 nu1 #gc4 sigma1 #gc4 ,sigma #aicb1 #gb4 ,temporary star3 #ahff1 #gc4 ,,corvus1 ,map ,no4 #h1 #eh4 ,star3 delta1 #eg4 ,,crater1 ,map ,no4 #h1 #eh4 ,variable3 ,r1 #eg4 ,,cygnus1 ,map ,no4 #ag1 #ii4 ,stars3 beta 7,albireo71 #ajc4 delta1 #ajd4 lambda1 #aje4 1 #aje4 omicron#b1 #ajd4 chi 7#ag71 #ajd4 psi1 #ajd4 #di1 #ajd4 #eb1 #ajd4 #fa1 #aje4 ,temporary star3 #ahgf1 #aje4 ,cluster3 #dfha1 #aje4 ,variable3 chi1 #ajd4 ,,delphinus1 ,map ,no4 #af1 #ie4 ,stars3 alpha1 #if4 beta1 #if4 gamma1 #id4 ,,draco1 ,map ,no4 #ae1 #ia2 ,map ,no4 #bf1 #acg4 ,stars3 gamma1 #ic4 epsilon1 #ic4 eta1 #ic4 1 #ic4 nu1 #ic4 ,sigma #aihd1 #ic4 ,sigma #bjed1 #ic4 ,sigma #bjgh 7#ag71 #ic4 ,sigma #bcbc1 #ic4 ,nebul3 #dcgc1 #ic4 #ddae1 #id4 ,,equuleus1 ,map ,no4 #ah1 #ajg4 ,stars3 beta1 #aji4 gamma1 #aji4 ,sigma #bgce1 #ajh4 ,sigma #bgcg1 #ajh4 ,sigma #bgdb1 #ajh4 ,sigma #bgdd1 #ajh4 ,,eridanus1 ,map ,no4 #ba1 #aae4 ,stars3 gamma1 #aad4 omicron#b1 #aaf4 #ab1 #aad4 ,sigma #dgj 7#cb71 #aad4 ,sigma #eaf 7#ci71 #aad4 ,sigma #eij1 #aaf4 ,nebula3 #hbf1 #aaf4 ,,gemini1 ,map ,no4 #d1 #ci4 ,stars3 alpha 7,castor71 #ch4 beta 7,pollux71 #dj4 gamma1 #dc4 delta1 #da4 epsilon1 #dc4 zeta1 #da4 eta1 #db4 kappa1 #dj4 lambda1 #dc4 1 #dc4 pi1 #dj4 #ae1 #dc4 #ch1 #dc4 ,cluster3 #acfj1 #db4 ,variables3 zeta1 #da4 eta1 #db4 ,r1 #da4 ,s1 #da4 ,t1 #da4 ,u1 #da4 ,nebula3 #aecb1 #da4 ,,hercules1 ,map ,no4 #ad1 #hg2 ,map ,no4 #ae1 #ia4 ,stars3 alpha1 #hi4 gamma1 #hi4 delta1 #hi4 zeta1 #hi4 kappa1 #hi4 1 #ij4 rho1 #ij4 #db1 #ij4 #ie1 #ij4 ,sigma #baja1 #ij4 ,sigma #bajd1 #ij4 ,sigma #bbae1 #ij4 ,sigma #bbhi1 #ij4 ,nebul3 #dbcj 7,m #ac71 #ib4 #dbcd1 #ib4 ,,hydra1 ,map ,no4 #c1 #cd2 ,map ,no4 #h1 #eh2 ,map ,no4 #aj1 #fe4 ,stars3 alpha1 #ef4 epsilon1 #cf4 theta1 #cf4 ,bu4 #cci1 #ef4 ,sigma #abde1 #cf4 ,variable3 ,r1 #ei4 ,nebul3 #bajb1 #ef4 #cabh1 #ei4 ,,lacerta1 ,map ,no4 #ag1 #ii4 ,,leo1 ,map ,no4 #f1 #ec4 ,stars3 gamma1 #eb4 iota1 #eb4 tau1 #eb4 #di1 #eb4 #ed1 #eb4 #hh1 #eb4 #ij1 #eb4 ,variable3 ,r1 #eb4 ,nebula3 #ahfa1 #eb4 ,,leo ,,minor1 ,map ,no4 #bf1 #acg4 ,,lepus1 ,map ,no4 #a1 #ba2 ,map ,no4 #b1 #ca4 ,stars3 alpha1 #cj4 beta1 #cj4 gamma1 #cj4 iota1 #cj4 #de1 #cj4 ,variable3 ,r1 #bi4 ,,libra1 ,map ,no4 #aj1 #fe4 ,stars3 ,a1 #fd4 alpha1 #fd4 beta1 #fd4 iota1 #fd4 ,variable3 delta1 #fd4 ,,lynx1 ,map ,no4 #e1 #de4 ,stars3 #d1 #ea4 #e1 #ea4 #ab1 #ea4 #ad1 #ea4 #ai1 #ea4 #ch1 #eb4 ,sigma #ieh1 #ea4 ,sigma #ajji1 #ea4 ,sigma #accc1 #ea4 ,,lyra1 ,map ,no4 #ag1 #ii4 ,stars3 alpha 7,vega71 #ig4 beta1 #ajj4 epsilon1 #ih4 zeta1 #ajj4 #ag1 #ajc4 ,variable3 beta1 #ajj4 ,nebula3 #dddg 7,ring71 #ajb4 ,,monoceros1 ,map ,no4 #a1 #ba2 ,map ,no4 #c1 #cd4 ,stars3 #d1 #ce4 #h1 #ce4 #aa1 #ce4 ,sigma #iba1 #ce4 ,sigma #ich1 #ce4 ,sigma #iej1 #ce4 ,sigma #aahc1 #ce4 ,sigma #aaij1 #ce4 ,clusters3 #adbd1 #ce4 #adfe1 #cf4 #adhc1 #cf4 #afaa1 #cf4 #afcg1 #cf4 ,variable3 ,s1 #ce4 ,,ophiuchus1 ,map ,no4 #ab1 #gg2 ,map ,no4 #ad1 #hg4 ,stars3 lambda1 #hf4 tau1 #hf4 #cf1 #gi4 #ci1 #gi4 #fg1 #hf4 #gj1 #hf4 #gc1 #hf4 ,sigma #baff1 #hf4 ,sigma #bagc1 #hf4 ,temporary star3 #afjd1 #hj4 ,clusters3 #dbaa1 #gi4 #dbef1 #hh4 #dbfd1 #gi4 #dbfh1 #gi4 #dbfi1 #gi4 #dbgj1 #gi4 #dcae1 #hh4 #dcdf1 #gi4 #ddaj1 #hh4 ,variable3 ,r1 #hj4 ,,orion1 ,map ,no4 #a1 #ba4 ,stars3 alpha 7,betelgeuse71 #bg4 beta 7,rigel71 #bj4 delta1 #bc4 zeta1 #bc4 eta1 #bd4 theta 7,trapezium71 #be4 iota1 #bg4 lambda1 #bh4 rho1 #bh4 sigma1 #bd4 tau1 #bh4 psi#b1 #bi4 ,sigma #fbg1 #bh4 ,sigma #fbi1 #bh4 ,sigma #feb1 #bh4 ,sigma #gbe1 #bd4 ,sigma #gbh 7,a #cb71 #bh4 ,sigma #gbi1 #bi4 ,sigma #gdg1 #bg4 ,sigma #gej1 #bg4 ,sigma #gie 7#eb71 #bg4 ,sigma #haf1 #bi4 ,omicron ,sigma #ih 7i71 #bh4 ,clusters3 #ije1 #bi4 #aahd1 #bg4 #acfa1 #bi4 #acgf1 #bi4 ,nebul3 ,great ,orion ,nebula1 #be4 #abbg1 #bc4 #abfg1 #bi4 ,,pegasus1 ,map ,no4 #ai1 #aaj4 ,stars3 beta1 #aji4 gamma1 #aji4 epsilon1 #aji4 eta1 #aji4 ,,perseus1 ,map ,no4 #bd1 #abe4 ,stars3 epsilon1 #abi4 zeta1 #acj4 eta1 #abi4 ,clusters3 #eab1 #abi4 #eba1 #abi4 ,variable3 beta 7,algol71 #acj4 ,,pisces1 ,map ,no4 #ah1 #ajg2 ,map ,no4 #bj1 #aab2 ,map ,no4 #bb1 #aai4 ,stars3 alpha1 #aag4 zeta1 #aag4 psi1 #aag4 #ee1 #aag4 #fe1 #aag4 #ff1 #aag4 #gg1 #aag4 ,variable3 ,r1 #aah4 ,,sagitta1 ,map ,no4 #af1 #ie4 ,stars3 epsilon1 #id4 zeta1 #id4 theta1 #id4 ,nebula3 #degb1 #id4 ,,sagittarius1 ,map ,no4 #ab1 #gg2 ,map ,no4 #ac1 #hc4 ,stars3 1 #hj4 #ed1 #hd4 ,clusters3 ,m #be1 #ha4 #dcee1 #ha4 #dcfa 7,m #h71 #ha4 #dcig 7,m #bd71 #ha4 #ddbd1 #hd4 ,variables3 ,r1 #hd4 ,t1 #hd4 ,u1 #hb4 ,v1 #hb4 ,,scorpio1 ,map ,no4 #ab1 #gg4 ,stars3 alpha 7,antares71 #ge4 beta1 #gf4 nu1 #gf4 xi1 #gf4 sigma1 #gf4 ,temporary star3 #ahfj1 #gh4 ,clusters3 #dagc1 #gh4 #dahc1 #gh4 ,,scutum ,,sobieskii1 ,map ,no4 #ab1 #gg2 ,map ,no4 #ac1 #hc4 ,stars3 ,sigma #bcjf1 #hb4 ,sigma #bcbe1 #hb4 ,clusters3 #ddjj1 #hb4 #ddbf1 #hb4 #ddcg1 #hb4 ,variable3 ,r1 #hb4 ,nebula3 #ddda1 #hb4 ,,serpens1 ,map ,no4 #ab1 #gg2 ,map ,no4 #ad1 #hg4 ,stars3 alpha1 #hf4 beta1 #hf4 delta1 #hf4 theta1 #hh4 nu1 #hf4 ,variable3 ,r1 #hf4 ,,taurus1 ,map ,no4 #bc1 #aba4 ,stars3 alpha 7,aldebaran71 #abc4 eta 7,alcyone71 #abj4 theta1 #abc4 kappa1 #abc4 sigma1 #abd4 tau1 #abd4 phi1 #abc4 chi1 #abc4 #cj1 #abb4 ,sigma #dab 7#g71 #abj4 ,sigma #dcj1 #abb4 ,sigma #fgd1 #abd4 ,sigma #gaf1 #abd4 ,clusters3 ,hyades1 #abj4 ,pleiades1 #abj4 #ajcj1 #abd4 ,variable3 lambda1 #abb4 ,nebul3 in ,pleiades1 #abj4 #aaeg 7,crab ,net71 #abd4 ,,triangulum1 ,map ,no4 #bd1 #abe4 ,star3 #f1 #abi4 ,nebula3 #ceb1 #abi4 ,,ursa ,,major1 ,map ,no4 #bf1 #acg4 ,stars3 zeta 7,mizar71 #ace4 iota1 #ace4 nu1 #ace4 xi1 #ace4 sigma#b1 #ace4 #bc1 #ace4 #eg1 #ace4 #fe1 #ace4 ,nebul3 #aidi1 #acf4 #aiej1 #acf4 #bcdc1 #acf4 ,,ursa ,,minor1 ,map ,no4 #bf1 #acg4 ,stars3 alpha 7,pole ,star71 #ach4 pi1 #ach4 ,,virgo1 ,map ,no4 #i1 #fa4 ,stars3 alpha 7,spica71 #ei4 gamma1 #ei4 theta1 #fj4 #hd1 #fb4 ,sigma #affi1 #ei4 ,sigma #ahdf1 #fb4 ,variables3 ,r1 #fc4 ,s1 #fc4 ,u1 #fc4 ,nebul3 ,field of the1 #fb4 #bhjf1 #fc4 #bifa1 #fc4 #caje1 #fc4 ,,vulpecula1 ,map ,no4 #ag1 #ii4 ,star3 ,sigma #bfie1 #ajf4 ,temporary star3 #afgj1 #ajf4 ,nebula3 #decb 7,dumb ,bell71 #ajf4 ,,the ,,moon1 most interesting of telescopic objects1 #aef2 telescopic views of moon reversed1 #aeg4 ,craters1 ring mountains1 and ringed plains3 ,agatharchides1 #agi4 ,agrippa1 #afh4 ,albategnius1 #aga4 ,alhazen1 #afj4 ,aliacensis1 #aga4 ,alphonsus1 #agf4 ,archimedes1 #age4 ,ariadus1 #afh4 ,aristarchus1#agd4 ,aristillus1 #afg4 ,aristoteles1 #afb4 ,arzachel1 #agf4 ,atlas1 #afj4 ,autolycus1 #afg4 ,bailly1 #agh4 ,ball1 #agf4 ,barrow1 #afb4 ,beer1 #age4 ,berzelius1 #afj4 ,billy1 #agi4 ,bullialdus1 #ahj4 ,burckhardt1 #aeg4 ,capuanus1 #agi4 ,cassini1 #afg4 ,catharina1 #agj1 ,cichus1 #agi4 ,clavius1 #agh4 ,cleomenes1 #aei4 ,condorcet1 #afj4 ,copernicus1 #age4 ,cyrillus1 #agj4 ,dlisle1 #agd ,endymion1 #afj4 ,eratosthenes1 #age4 ,eudoxus1 #afb4 ,euler1 #agd4 ,firmicus1 #afj4 ,fracastorius1 #afi1 #agi4 ,furnerius1 #afa4 ,gassendi1 #agi4 ,gauss1 #aei4 ,geminus1 #afj4 ,goclenius1 #afi4 ,godin1 #afh4 ,grimaldi1 #agi4 ,guttemberg1 #afi4 ,hainzel1 #agi4 ,hansen1 #afj4 ,helicon1 #agd4 ,hell1 #agf4 ,hercules1 #afj4 ,herodotus1 #agd4 ,herschel1 ,caroline1 #agd4 ,hipparchus1 #aga4 ,humboldt1 #afa4 ,hyginus1 #afh4 ,julius ,csar1 #afh4 ,kepler1 #agf4 ,lambert1 #agd4 ,landsberg1 #ahj4 ,langrenus1 #afj1 #afh4 ,letronne1 #agi4 ,leverrier1 #agd4 ,lexell1 #agf4 ,lichtenberg1 #agd4 ,linn1 #afe4 ,longomontanus1 #agh4 ,macrobius1 #aei4 ,maginus1 #agh4 ,manilius1 #aff4 ,maurolycus1 #agb4 ,menelaus1 #aff4 ,mercator1 #agi4 ,mersenius1 #agi4 ,messala1 #afj4 ,messier1 #afi4 ,newton1 #agh4 ,petavius1 #afj1 #afh4 ,picard1 #aeg4 ,piccolomini1 #aga4 ,pico1 #agb4 ,plato1 #agb4 ,plinius1 #aff4 ,posidonius1 #afc1 #afd4 ,proclus1 #aeh4 ,ptolemus1 #agf4 ,purbach1 #agf4 ,sacrobosco1 #aga4 ,schickard1 #agh4 ,schiller1 #agh4 ,silberschlag1 #afh4 ,stfler1 #aga4 ,sulpicius ,gallus1 #aff4 ,thetetus1 #afg4 ,thebit1 #agf4 ,theophilus1 #agj4 ,timocharis1 #agd4 ,tobias ,mayer1 #agf4 ,tralles1 #aei4 ,triesnecker1 #afh4 ,tycho1 #agg1 #agh4 ,vendelinus1 #afj1 #afh4 ,vieta1 #agi4 ,vitello1 #agi4 ,walter1 #aga4 ,wargentin1 #agi4 ,werner1 #aga4 ,wilhelm ,i1 #agh4 ,maria1 or ,seas3 ,lacus ,somniorum1 #afc4 ,mare ,crisium1 #aeg1 #aei1 #afj4 ,mare ,fecunditatis1 #afj1 #afh4 ,mare ,frigoris1 #afb1 #agb4 ,mare ,humboldtianum1 #afj4 ,mare ,humorum1 #agf1 #agi4 ,mare ,imbrium1 #afc1 #agb1 #agd4 ,mare ,nectaris1 #afh4 ,mare ,nubium1 #agf4 ,mare ,serenitatis1 #afc1 #afd1 #afe4 ,mare ,tranquilitatis1 #afh4 ,mare ,vaporum1 #aff1 #afg4 ,oceanus ,procellarum1 #agb1 #agf1 #agi4 ,palus ,nebularum1 #afg4 ,palus ,putredinis1 #afg4 ,palus ,somnii1 #aei4 ,sinus stuum1 #agb4 ,sinus ,iridum1 #agb1 #agc4 ,other formations3 ,alps ,mountains1 #afc4 ,apennine ,mountains1 #afc1 #afg1 #age4 ,cape ,agarum1 #aeh4 ,cape ,heraclides1 #agc4 ,cape ,laplace1 #agc4 ,carpathian ,mountains1 #agf4 ,caucasus ,mountains1 #afc4 ,cordilleras ,mountains1 #ahj4 ,d',alembert ,mountains1 #ahj4 ,drfel ,mountains1 #ahj4 ,hmus ,mountains1 #afe4 ,harbinger ,mountains1 #agd4 ,leibnitz ,mountains1 #ahj4 ,lunar ,railroad1 #agf4 ,mt4 ,argus1 #afe1 #afg4 ,mt4 ,hadley1 #afg4 ,mt4 ,huygens1 #age4 ,pyrenees ,mountains1 #afi4 ,taurus ,mountains1 #afd4 ,,the ,,planets3 ,are there planets among the stars8 #ahc4 ,mars1 two views of1 #ag4 best advertised of planets1 #aea4 favorable oppositions of1 #aeb4 seen with #e-;inch telescope1 #aeb4 polar caps of1 #aeb4 color of1 #aeb4 dark markings on1 #aeb4 canals1 #aec4 earthlike condition of1 #aec4 ,mercury1 phases of1 #aee4 peculiar rotation of1 #aee4 markings on1 #aee4 probably not habitable1 #aee4 ,jupiter1 easiest planet for amateurs1 #ada4 seen with #e-;inch glass1 #ada4 satellites1 swift motions of1 #adb4 velocity of planet's equator1 #adb4 how to see all sides of1 #adb1 #adc4 watching rotation of1 #adc4 eclipses and transits of satellites1 #add1 #adg4 belts and clouds of1 #ade4 different rates of rotation1 #ade4 names and numbers of satellites1 #adf4 ,saturn1 next to ,jupiter in attractiveness1 #adg4 seen with #e-;inch glass1 #adh4 its moons and their orbits1 #adh1 #adi4 polar view of system1 #adi4 ,roche's limit1 #adi1 #aej4 origin of the rings1 #aej4 ,pickering's ninth satellite1 #aea4 the satellites as telescopic objects1 #aea4 ,venus1 her wonderful brilliance1 #aec4 her atmosphere seen1 #aec4 ,lowell's observations1 #aec4 ,schiaparelli's observations1 #aed4 her peculiar rotation1 #aed4 how to see1 in daytime1 #aee4 ,neptune and ,uranus1 #aee4 ,,the ,,sun1 #aha4 shade glasses for telescopes in viewing1 #aha4 solar prism1 #aha4 helioscope1 #aha4 periodicity of spots1 #aha4 to see1 by projection1 #ahb4 spectroscope for solar observation1 #ahb4 ,,the ,,telescope3 refractors and reflectors1 #b1 #h4 eyepieces1 #f1 #i1 #aj4 aberration 7chromatic71 #f2 7spherical71 #f1 #ag4 achromatic telescopes1 how made1 #g4 object glass1 #h4 magnifying power1 #aa4 mountings1 #ab4 rules for testing1 #ac4 image of star in1 #ad4 image in and out of focus1 #ad1 #ae1 #ag4 astigmatism1 #af4 ,,the ,,end ,illustration #afib ,s4 ,pleasures of the ,telescope ,,garrett ,p4 ,,serviss ,this book says to the amateur1 in effect3--,what if you have not all advantages of clockwork and observatory equipment4 ,you may know something of the witchery of the heavens even with a little telescope of three to five inches aperture6 ,pleasures of the ,telescope is popular in style rather than technical4 ,for setting forth the chief attractions of the starry heavens1 a complete set of star-maps is included1 showing all the stars visible to the naked eye in the regions of sky represented1 and in addition some stars that can only be seen with optical aid4 ,in six chapters these twenty-six maps are described so plainly that the amateur can readily find all the interesting star-groups1 clusters1 and nebul1 and also the colored or double stars4 ,in the three concluding chapters the moon and planets receive special consideration4 ,in the opening chapter the amateur is told how to select and test a glass4 ,booklovers ,bulletin4 ,transcriber's ,note ,minor errors and inconsistencies in punctuation and hyphenation have been silently corrected4 ,some illustrations have been relocated a short distance within the text4 ,original page numbers have been retained in the index4 ,greek letters1 used to identify stars1 are replaced with the full name of the ,greek letter1 e4g4 alpha4 ,upper case ,greek letters are shown by capitalising the initial letter1 e4g4 ,sigma #aabf ,a caret 77 is used to represent superscripts1 e4g4 nu#a and nu#b ,the following minor corrections have also been made3 p#c3 wil has been corrected to will4 p#bh3 ,sigma #fbi is not shown on ,map ,no4 #a4 ,the location of m ,orionis is marked as ,sigma #fif4 ,this inconsistency has not been corrected4 p#ed3 for colors has been corrected to four colors4 p#fh3 #a1jfe1gij1bej1jjj1jjj has been corrected to #a1jfe1gjb1ejj1jjj1jjj4 p#afc-afd3 magnical has been corrected to magical4 p#agi3 ,a repeated and has been removed4