,illustration3 ,frontispiece--,,building
 ,,and ,,dome ,,from ,,south            
,,department ,,of ,,the ,,interior      
,hon4 ,charles ,stewart                 
,minister    ,w4 ,w4 ,cory1 ,c4,m4,g4   
,deputy ,minister        ,the           
,dominion ,astrophysical    ,observatory
      ,victoria1 ,b4,c4      ,a sketch  
of the development of astronomy    in   
,canada and of the founding of this     
observatory4    ,a description of the   
building and of the    mechanical and   
optical details of the telescope4 ,an   
account of the principal work of the    
institution4      ,by    ,j4 ,s4        
,plaskett1 ,f4,r4,s4        ,ottawa     
,f4 ,a4 ,,acland1    ,printer to the    
,king's ,most ,excellent ,majesty       
#aibc          ,,staff ,,of ,,the       
,,observatory3        ,director         
,j4 ,s4 ,plaskett1 ,b4,a41 ,d4,sc41     
,f4,r4,s4,c41 ,f4,r4,s4    ,research    
,astronomer                             
,w4 ,e4 ,harper1 ,m4,a4    ,astronomer  
,reynold ,k4 ,young1 ,ph4,d41           

,f4,r4,s4,c4    ,astronomer             
,h4 ,h4 ,plaskett1 ,b4,a4    ,secretary 
,miss ,h4 ,r4 ,keay    ,observing       
,assistant                           ,t4
 ,t4 ,hutchison1 ,esq4          ,,the   
,,dominion ,,astrophysical ,,observatory
    ,,victoria1 ,b4,c4    ,by ,j4 ,s4   
,,plaskett1 ,director4                  
,,section #a4--;,,history ,,and         
,,construction      ,introduction       
,this description of the observatory1   
its equipment and work has been  written
 by the director in response to a need1 
frequently expressed  by the numerous   
visitors to the institution1 of a       
non-technical  account of the principles
 of the telescope and of the work of the
  institution4 ,this account will       
commence by a short historical sketch   
of the beginnings of the undertaking    
followed by a description of the        
observatory and telescope and concluded 
by a resume of its work4                
,historical ,sketch    ,this observatory
 is a branch of the ,department of the  

,interior  of the ,federal ,government1 
the department which has charge of  the 
administration of the western lands of  
the ,dominion4 ,in the  colonization of 
these lands1 one of the obvious first   
needs was a  survey of the boundaries   
and subdivision into townships and      
sections4  ,this need led to the        
organization of a surveys branch of the 
department  and out of the necessity of 
accurate astronomical observations to   
delimit the boundaries and define the   
position of the base lines  for         
subdivision work arose the astronomical 
branch4 ,the first ,chief  ,astronomer  
of ,canada1 the late ,dr4 ,w4 ,f4 ,king1
 was a man of sterling  integrity and   
remarkable ability and to his genius    
must be ascribed in  large degree the   
present development of astronomy in     
,canada4 ,as ,chief  ,astronomer and ,h4
 ,m4 ,commissioner of ,international    
,boundaries1 he  early realized the need
 of an observatory for an initial       
meridian1 for  housing and standardizing

 the instruments1 and for some          
astronomical  research4 ,he was         
successful in having the fine ,dominion 
,observatory  erected on the            
,experimental ,farm1 ,ottawa1 in #aije  
which housed the  ,astronomical ,branch1
 the staff of the ,international        
,boundary ,surveys  and later the       
,geodetic ,survey of ,canada1 of which  
he was the first  superintendent4       
,the ,dominion ,observatory was equipped
 with a #ae-;inch refractor  provided   
with micrometer1 photometer1 solar and  
stellar cameras1  and spectrograph4 ,the
 writer was entrusted with the work with
 this  telescope and the spectroscopic  
work especially was energetically       
developed and helped1 with the other    
activities of the institution1 to  bring
 gratifying recognition from the        
scientific world4 ,the need of a  larger
 aperture for extending this part of the
 work was soon realized  by the writer  
and was brought to the attention of the 
,government4  ,after some delays1 owing 

to various circumstances1 it was finally
  decided early in #aiac to provide a   
large reflector for extending  the work4
 ,enquiries were at once made1          
specifications prepared and  estimates  
obtained from prospective makers of the 
instrument4 ,contracts  were finally    
awarded in ,october #aiac to the ,john  
,a4 ,brashear ,co4 of  ,pittsburgh for  
the optical parts and to the ,warner    
,swasey ,co4 of  ,cleveland for the     
mechanical parts of a #gb-;inch         
reflecting telescope4      ,location    
,it was necessary to know the location  
of the instrument before the  design of 
the mounting could be completed as the  
angle of the polar  axis depends upon   
the latitude of the site4 ,when the new 
telescope  was first proposed there was 
no thought of locating elsewhere than at
  the seat of government at ,ottawa4    
,however1 upon further consideration  it
 was decided that the telescope should  
be located where1 in ,canada1  the best 
observing conditions prevailed4 ,to     

determine this location  preliminary    
selection of five likely stations was   
made by the aid of  ,sir ,frederic      
,stupart1 chief of the ,meteorological  
,service from the  meteorological       
records4 ,these stations1 at ,ottawa1 at
 ,medicine ,hat1  at ,banff1 at         
,penticton1 and at ,victoria were       
occupied by ,mr4 ,w4 ,e4  ,harper1      
astronomer at ,ottawa and the           
astronomical conditions were  observed  
by means of a #d4e-;inch telescope4     
,victoria was unmistakably  superior in 
8seeing0 or defining power1 in low      
diurnal and seasonal  range of          
temperature and about equal so far as   
quantity of clear sky is  concerned4    
,for such a large telescope as a        
#gb-;inch there could be no  question of
 the marked astronomical advantages of  
such a location1 and  it was therefore  
decided to locate the telescope at      
,victoria4 ,while the  observatory      
should not be in the city itself it     
should not be too far  away1 not only on

 account of accessibility and facility  
in obtaining  supplies1 but also the    
advantageous conditions of good seeing1 
low  diurnal range of temperature and   
small rainfall were confined to a       
relatively small area near ,victoria4   
,an isolated monadnock called  locally  
,little ,saanich ,mountain but now named
 ,observatory ,hill1 was  selected4     
,this hill is about #g miles north of   
,victoria and has a main  road and an   
interurban railway passing its base4 ,it
 has an elevation of  #gcj feet1        
sufficient area around the summit for   
all necessary buildings  and was by far 
the most suitable site available4       
,construction    ,the ,provincial       
,government had generously agreed to    
give #aj1jjj for the  purchase of a site
 and to build a road to the summit4     
,this undertaking  was fully met and the
 road1 splendidly located and           
constructed and  costing over #be1jjj1  
was completed in the spring of #aiae4   
,contracts  for the construction of the 

telescope pier and the circular steel   
walls of the building were awarded to a 
local firm and this work  was completed 
in #aiaf4 ,the revolving dome with      
accessories for the  operation of the   
telescope was made by the ,warner       
,swasey ,co41 the  builders of the      
telescope mounting1 and was completed   
and erected in  #aiaf1 thus making the  
building ready for the telescope4       
,the design of the mounting was very    
carefully gone into by the ,warner      
,swasey ,co4 in collaboration with the  
writer and was completed in the  autumn 
of #aiad4 ,construction was at once     
begun and the mounting was  completed   
and temporarily erected at ,cleveland in
 ,may #aiaf4 ,it was then  shipped to   
,victoria and permanently erected in its
 building by ,november  #aiaf4    ,the  
order for the large disc for the        
#gb-;inch mirror and for an  auxiliary  
flat of #ee inches diameter for testing 
the #gb-;inch was given  to the ,st4    
,gobain ,glass ,works of ,paris by the  

,jno4 ,a4 ,brashear ,co4  as soon as the
 contract was awarded4 ,the #gb-;inch   
disc was cast and  annealed by ,june    
#aiad and was fortunately shipped at    
once without  waiting for the #ee-;inch 
disc4 ,it left ,antwerp only about a    
week before  war was declared and it was
 only by this small margin that ,canada 
now  has a #gb-;inch telescope4         
,grinding and polishing were at once    
begun  but the lack of the large flat   
and other difficulties delayed the      
completion and it was not until ,april  
#aiah1 about a year and a half  after   
the completion of the mounting1 that the
 figuring was finally  completed and the
 telescope ready for work4              
,nevertheless1 for an  undertaking of   
such magnitude the work was completed in
 record time1  four and a half years    
after the awarding of the contracts4    
,,section #b4--,,the ,,building ,,and   
,,dome      ,the ,observatory ,building 
,the building for housing a large       
reflecting telescope requires to  be of 

special design for the best results4 ,it
 should not rise above  the shade       
temperature during the day and should   
rapidly assume and  follow the external 
temperature at night4 ,such materials as
 brick or  stone are obviously not      
suitable and all recent telescope       
buildings  are entirely of metallic     
construction in order to assume quickly 
the  night temperature1 and of          
double-walled1 ventilated type to       
prevent  overheating from the sun's     
rays4 ,the building for the #gb-;inch   
telescope  is entirely of steel         
construction1 circular in form1 #ff feet
 in  external diameter and with vertical
 walls #cb feet high4 ,a view from  the 
south is given in the ,frontispiece and 
from the north in ,fig4 #a1  showing the
 city of ,victoria and the straits of   
,juan de ,fuca in the  background4 ,an  
external and internal covering of       
galvanized iron  separated by about #af 
inches allows free circulation of air   
from a  peripheral opening at the base  

up through a similar double walled dome 
and out of louvres at the top4 ,the     
ground floor of ,terrazo is laid        
directly on the rock base and the       
observing floor #bb feet above this  is 
formed of steel girders and checkered   
steel plate4 ,in the centre of  the     
ground floor rises the massive pier to  
support the telescope1 of  reinforced   
concrete and symmetrical tapering form4 
,the pier is actually  double1 united   
below the observing floor by a massive  
reinforced arch  and extending above the
 floor as two piers 7see ,fig4 #b7 one  
for each  end of the polar axis4        
,temporary partitions on the ground     
floor provide  a dark room1 sleeping    
room1 and temporary office quarters4    
,illustration3 ,fig4 #a4--,,observatory 
,,building ,,from ,,the ,,north         
,the ,dome    ,this circular steel      
building is capped by a circular plate  
supported by  massive girders on which  
is placed a curved railroad iron rail   
turned  and adjusted perfectly level and

 circular4 ,the hemispherical dome turns
  on this rail on #bd massive wheels    
mounted on roller bearings and is       
rotated by an electric motor mechanism  
operated by reversing switches  on each 
side of the south pier4 ,the framework  
of this dome1 which is  #ff feet in     
external diameter and about #ch feet    
high1 the lower #e feet  being          
cylindrical1 consists essentially of a  
circular base to which  the bearing     
wheels are attached and two double1 very
 deep and rigid  main ribs1 one of which
 can be seen in ,fig4 #c1 #af feet apart
 in the  clear and extending parallel to
 each other entirely across the dome4   
,these are united #f feet beyond the    
zenith by a cross girder and this       
opening1 which can be revolved to any   
azimuth and can be closed by  double    
motor operated shutters1 enables the    
telescope to observe at any  part of the
 sky4 ,auxiliary circular ribs reaching 
from the base ring  up to the main ribs 
all around the dome except at the       

shutter opening1  form the support for  
the double steel covering of #ab inches 
separation4  ,this ventilating space is 
united through suitable weather guards  
with  the space between the building    
walls and forms the protection against  
overheating by the sun in the day time4 
,dome ,accessories    ,the shutter      
opening #af feet wide and extending from
 the base of the  dome to #f feet beyond
 the zenith is closed by a double       
shutter also  double walled and         
ventilated4 ,canvas screens mounted on  
tubes and  operated by motor can be run 
up from the base of the shutter opening1
  this one being shown in ,fig4 #c1 and 
down from the top so as to limit  the   
opening to the width of the tube of the 
telescope4 ,these screens  are necessary
 when the wind is blowing to prevent    
shaking of the tube  and consequent     
jumping of the star image4 ,for enabling
 the observer  to reach conveniently the
 upper end of the telescope tube in any 
position a counterweighted elevating    

platform1 moved up and down the  shutter
 opening by motor and drum with lifting 
cables is provided4  ,this platform is  
#bj feet long and #d feet wide with a   
wing at each end1  extending inwards    
about #f feet1 on which the observer can
 stand and  can move it and himself by a
 hand wheel up to and partly encircling 
the telescope tube4 ,the platform and   
movable wings1 which are well  shown in 
,fig4 #c1 can be brought to any desired 
height by an operating  switch at one   
side and can be reached by an auxiliary 
stairway from a  small stationary       
platform attached to the base ring of   
the dome4 ,this  stationary platform is 
reached from the observing floor by a   
permanent  stairway moving with the dome
 and extending to a foot from the floor4
  ,platform wings and stairways are made
 safe for observers by guard and  hand  
rails #cj inches high4 ,this moving     
platform1 an essential accessory  for   
direct photography and other work at the
 principal focus of the  telescope1     

meets1 in a more convenient and         
satisfactory manner than any  other     
previous device for the purpose1 all the
 observing requirements  for work at the
 upper end of the tube4      ,mechanism 
for ,silvering    ,in order to renew the
 silver coating on the upper surface of 
the  mirror1 which is necessary about   
three times a year1 mechanism has to  be
 provided for handling the mirror and   
its cell1 the lower section of  the     
telescope tube1 with ease and safety4   
,the mirror weighs over #b tons  and the
 cell #d tons1 so #f tons have to be    
removed from and replaced  on the       
telescope tube4 ,this is effected by    
means of the silvering  car1 which can  
be seen at the left of ,fig4 #b1 a      
massive framework of  structural steel  
rolling on four flanged wheels on flush 
tracks in  the observing floor4 ,with   
the tube turned to a vertical position1 
the  car is rolled from its normal      
position at the east side of the dome   
directly under the tube and a           

motor-operated screw-jack surmounted by 
a triangular rocking arm can be brought 
up against the bottom of the  cell4 ,on 
removing the attaching bolts1 cell and  
mirror can be lowered  and rolled on the
 car to the east out of the way4 ,the   
removal of #f tons  from one side throws
 the telescope out of balance and so the
 outboard  end of the declination axis  
is supported by a counterweighted strut 
run up through the floor and the upper  
end of the tube tied to rings  at the   
top of the dome4 ,with a band of        
paraffined paper tied around  the edge  
of the mirror and a plug in the central 
hole1 the silvering  solution can be    
poured on and evenly flowed over the    
surface by rocking  on a steel ball at  
the top of the jack-screw4 ,when the    
silvering is  complete1 cell and mirror 
are replaced in the reverse order and   
the  car rolled back out of the way4    
,the operation takes about a day and is 
performed with perfect safety and ease4 
,illustration3 ,fig4 #b4--,,telescope   

,,in ,,average ,,observing ,,position   
,,section #c4--,,mechanical ,,parts ,,of
 ,,telescope      ,introduction    ,it  
is useful1 before describing the        
mechanical parts or mounting of  the    
telescope1 to explain the difference    
between the two kinds of  telescope1    
refracting and reflecting1 employed in  
astronomical work4  ,the refracting     
telescope is the most familiar type as  
the ordinary  spyglass or draw-tube     
telescope and the field or opera glass  
are all  refracting telescopes4 ,the    
refracting telescope is so called       
because  the light from the distant     
object is refracted through a lens at   
the  outer end of the tube and forms an 
image of the object at the inner  end1  
just as a camera forms an image on the  
ground glass or film1 and  this image is
 viewed and magnified by the eyepiece or
 ocular4 ,the  reflecting telescope on  
the other hand has the upper or outer   
end  of the tube open and the light from
 the distant object is reflected  7hence

 the name7 from a concave mirror at the 
lower end of the tube1  forming the     
image of the object at the top1 where it
 can be viewed and  magnified by the    
ocular as in the refractor4    ,each    
type of telescope has its astronomical  
advantages and  disadvantages4 ,the     
refractor is better suited for visual   
observations  such as the measurement of
 double stars and the study of planetary
  detail and is less affected by        
temperature changes than the reflector4 
,on the other hand the reflector1 on    
account of its perfect achromatism1  is 
the instrument par excellence for       
photographic observations1 and1 as  more
 than three-fourths of modern           
astronomical work is photographic1 it   
appears to be superseding the refractor4
 ,this advantage is increased  by the   
fact that the refractor has apparently  
reached the useful  limit in size and   
that it costs at least three times as   
much as a  reflector of the same        
aperture4 ,although each type of        

telescope has  its characteristic type  
of mounting for astronomical purposes1  
the  principles are the same for each   
and can probably be most easily         
followed by describing the essential    
parts of the mounting of the  #gb-;inch 
telescope4      ,the ,telescope ,tube   
,the tube performs the important        
function of carrying in relatively      
invariable position and adjustment the  
optical parts of the telescope4  ,the   
tube of the #gb-;inch telescope is #ca  
feet long1 #g feet #d inches  outer     
diameter and weighs #ae tons4 ,its form 
and construction are well  shown in     
,figs4 #b and #c4 ,it consists of the   
main or central section  ,a1 ,fig4 #b   
the lower section ,b which carries the  
main mirror and the  skeleton section ,c
 which carries the secondary mirrors4   
,the central  section is a cylindrical  
steel casting heavily ribbed on the     
inside  about #f feet high and weighs #g
 tons4 ,the lower section is securely   
bolted to it through the flanges shown  

and with the mirror and its  supporting 
mechanism weighs about #f tons4 ,the    
upper skeleton section  is built up of  
structural steel1 #c inch ,i beams1     
firmly braced and  rivetted together in 
the manner shown in the figures4 ,a     
special  feature of this skeleton tube1 
making it more rigid than any previous  
design1 consists of the diagonal tension
 rods in each rectangular  compartment  
screwed up each to a tension of about   
#b1jjj pounds1 so  that the whole tube  
is under tension in every position4     
,this stiffness  is essential for the   
proper performance of the optical parts1
 as the  principal and secondary mirrors
 at bottom and top of tube respectively 
should occupy the same relative         
positions in whatever direction the     
tube is pointed4      ,the ,declination 
,axis    ,the telescope tube is firmly  
screwed at right angles to the flanged  
end  of a massive shaft #af inches in   
diameter1 called the declination axis1  
extending through the cubical section ,d

 of the polar axis ,,nds1 ,fig4 #b1     
through the declination sleeve ,e into  
the housing ,f4 ,this declination  axis 
is rotated1 carrying the tube with it1  
on ball bearings in ,d and  ,f1 this    
rotation being effected by an electric  
motor with reduction  mechanism1 gearing
 into a large spur gear attached to the 
end of the  declination axis1 the whole 
being concealed within the declination  
housing ,f4 ,hence the tube can be      
turned at the rate of #de degrees to    
the minute to any required position up  
or down1 north or south4 ,the  position 
in the sky1 the declination1            
corresponding to latitude on the  earth1
 is read on a large circle graduated    
into degrees within ,f and  subdivided  
into #e minute intervals on the small   
auxiliary circle ,h4      ,the ,polar   
,axis    ,as positions north or south   
are given by turning the tube on the    
declination axis1 so positions east or  
west are given by rotation on  the polar
 axis1 so called because it points to   

the pole of the heavens  and is exactly 
parallel to the axis of the earth4 ,the 
,polar axis ,,nds  ,fig4 #b1 which is   
#ba feet long and weighs #ie tons1 is   
built up of  three steel castings1 a    
central cubical section ,d and two      
conical end  sections1 all securely     
bolted together and turning in ball     
bearings  on its ends4 ,the upper1      
north1 bearing is carried in an         
adjustable  pillow block1 by which the  
final parallelism with the earth's axis 
is  obtained1 bolted on the curved      
cement pier shown at the left or north  
in ,figs4 #b and #c4 ,the lower1 south1 
bearing is carried in a massive  cast   
iron pedestal bolted to the south cement
 pier4 ,the polar axis is  rotated on   
these bearings1 also at the rate of #de 
degrees per minute1  carrying the       
declination axis and tube with it to any
 position east or  west in the sky by an
 electric motor and reduction gearing   
concealed  within the south pedestal4   
,the position east or west in the sky1  

the  right ascension as it is called    
corresponding to longitude on the       
earth1 is read by means of a graduated  
circle shown above ,g1 ,fig4 #b1  which 
is divided into #bd hours and each hour 
into single minutes4 ,while  longitudes 
on the earth are occasionally expressed 
as so many hours  and minutes east or   
west of ,greenwich1 right ascensions in 
the sky are  almost invariably given in 
hours and minutes rather than degrees4  
,illustration3 ,fig4 #c4--,,telescope   
,,from ,,the ,,west      ,the ,driving  
,clock    ,it is evident1 by rotation of
 the telescope on the declination and   
polar axes by means of the quick-motion 
motors1 that the tube can be  pointed in
 any direction in the sky1 towards any  
star4 ,but owing to the  rotation of the
 earth on its axis from west to east1   
which is the cause  of the apparent     
motion of sun1 moon and stars from east 
to west1 the  telescope will be quickly 
carried eastward of the star which will 
only  remain for an instant in the      

field4    ,the mechanism by which the   
rotation of the earth is compensated for
  is called the driving clock and is    
contained in the case ,l1 ,fig4 #b1  at 
the north side of the south pier4 ,in   
the lower half of the case a  governor  
similar to the governor of a steam      
engine is driven once per  second by a  
train of gears in the upper section     
actuated by a weight  of #cjj pounds    
below the floor4 ,if the speed of the   
governor tends to  increase the balls   
raise by centrifugal force and bring    
increased  friction to bear thus        
reducing the speed to normal while if   
the speed  tends to decrease1 the balls 
drop and reduced friction quickly allows
  it to accelerate to normal speed4 ,a  
shaft with a coarse screw thread  on it1
 called technically a 8worm0 and        
situated at the top of the  case1 is    
driven by intermediate gearing from the 
governor at the  rate of one revolution 
every two minutes4 ,the thread on this  
shaft  engages into teeth cut in the    

worm wheel ,g1 ,fig4 #b1 which is #i    
feet in  diameter4 ,as there are #gbj   
teeth very accurately spaced in this    
worm  wheel1 it is driven around by the 
worm in #b  #gbj  #a1ddj minutes1 #bd   
hours1 the same rate as the earth4 ,this
 worm wheel1 normally loose  on the     
polar axis on which it turns on ball    
bearings1 allowing the  axis to be moved
 freely to any position1 can be rigidly 
clamped to it  by pressing a button4    
,when this is done1 it will evidently   
turn the  polar axis and hence the tube 
at the same rate as the earth but in the
  opposite direction1 on an axis        
parallel to the axis of the earth1 thus 
exactly compensating for the rotation of
 the earth4 ,hence any star  at which   
the telescope is pointed will           
automatically remain central  in the    
field4 ,owing to the great magnification
 all this mechanism  requires the       
highest grade of workmanship1 else there
 will be wandering  of the image1 a most
 annoying and troublesome defect4 ,few  

telescopes  are entirely free from      
periodic error and that the #gb-;inch   
drives  so regularly and smoothly is a  
great advantage and evidence of the     
perfection of workmanship throughout4   
,electric ,motions    ,it has already   
been described how the telescope can be 
moved by motors  north or south and east
 or west at the rate of #de degrees per 
minute4  ,these motors are operated from
 small switchboards on each side of  the
 south pier1 the one at the west being  
seen in ,figs4 #b and #c4 ,the          
left-hand reversing switch moves the    
telescope east or west1 the  centre     
switch north or south and the right-hand
 switch revolves the  dome east or west4
 ,in addition to these quick motions of 
the telescope  for rapidly bringing it  
to the approximate position1 much finer 
and  slower motions are required for    
bringing the image exactly central and  
for guiding4 ,these slow motions are    
also operated by electric motors        
actuated by two small aluminium         

switchboards attached by flexible       
cables to the top and bottom of the     
tube4 ,these switchboards can be        
carried in the hands of the observer or 
rested on the observing  ladder4        
,pressure on suitable buttons moves the 
telescope north or  south1 east or west 
at either one of two different speeds1 a
 speed of  one revolution in #cf hours  
for centering the image and a speed of  
one  revolution in #cj days for guiding1
 correcting for slight irregularities   
due to air disturbance or other causes4 
,although these speeds may seem         
excessively slow1 the motion of the     
image even with the monthly rate  is at 
once evident on pressing the button and 
faster speeds would make  accurate      
guiding difficult4 ,in addition to the  
two quick and two slow  motion motors   
there are two clamping motors and one   
for automatically  rewinding the clock  
weight1 seven in all4 ,these with the   
three motors  operating the dome are all
 continuous current motors which can be 

started and reversed more readily and   
have greater initial torque than        
alternating motors4 ,each motor is      
supplied with an automatic control1  so 
that all that is necessary is to throw  
the switch or press the  button to start
 or reverse4 ,current is supplied by a  
motor generator  set on the ground      
floor4      ,method of ,operation    ,a 
description of the method of setting    
upon the required star1 when1  for      
example1 photographing the spectra of   
the stars1 will help to make  the       
operation of the telescope more clearly 
understood4 ,it is easily  possible to  
pull the telescope around by hand to the
 required star  identified by eye among 
the constellations4 ,although the moving
 parts  of the telescope weigh nearly   
#de tons1 so perfect are the ball       
bearings  in which it turns that a      
weight of #c pounds at the upper end of 
the  tube is sufficient to set it in    
motion4 ,however the settings can be    
much more quickly and certainly made by 

turning the telescope to the  right     
ascension and declination of the star by
 the electrical motions4  ,a programme  
of the stars to be observed with their  
right ascensions and  declinations is   
prepared beforehand4 ,the observing     
assistant stands  beside the small      
switchboard on the south pier and       
rapidly moves the  telescope east or    
west and north or south until the       
indexes on the  graduated circles point 
to the tabulated positions1 while the   
dome can  be turned to the required     
position at the same time by means of   
the  third operating switch4 ,by        
pressing two buttons the telescope is   
then  firmly clamped and the driving    
clock starts the telescope automatically
  following the star4 ,in the meantime  
the observer has inserted the  plate    
holder in the spectrograph and drawn the
 slide and by means of  the aluminium   
switchboard brings the star1 which is   
generally near the  centre1 exactly to  
the centre of the finder1 when it will  

be visible on  the slit of the          
spectrograph through a guiding eyepiece 
and can quickly  be brought central and 
the exposure commenced4 ,the time       
required from  the end of one exposure  
to the beginning of the next1 unless the
 stars  are far apart in the sky1 does  
not generally exceed two minutes1 a     
shorter time than usually required for  
even quite small telescopes4  ,this     
rapid operation is due to special care  
in design and construction  and markedly
 increases the efficiency and capacity  
of the instrument4      ,special        
,features of the ,mounting    ,the      
mounting of the #gb-;inch telescope has 
several new features not  hitherto used 
and sets a new standard for convenience 
and accuracy of  operation4 ,the        
observatory is much indebted to the     
,warner  ,swasey ,co41  who have made   
most of the large mountings in ,america1
 for the spirit in  which they undertook
 and carried through this work4 ,their  
sole object  was to produce the best    

possible mounting regardless of cost and
 no  suggestion of the writer looking to
 improvement was refused4 ,to ,mr4      
,swasey1 the president1 are due many of 
the original features of the  mounting  
and the beauty and harmony of the       
design1 while ,mr4 ,burrell1  the works 
manager1 is responsible for the         
simplification of the  mechanism and the
 beautiful co-ordination of the details4
 ,no greater  testimony to the          
perfection of design and construction   
can be given  than to say that after    
five years use there is no feature the  
director  would wish changed1 and no    
single defect of construction has been  
revealed4    ,it may be of interest to  
note the principal improvements in this 
mounting4    #a4 ,all parts of the sky  
can be readily reached4 ,this is not    
possible  with all types of reflecting  
telescopes4    #b4 ,the elimination of  
cylindrical bearings with cumbrous      
friction-relieving devices1 formerly    
considered necessary for  maintaining   

collimation and adjustment on           
declination and polar  axes1 and the use
 of ball bearings for both              
friction-relieving and  collimating     
purposes has resulted in remarkable ease
 of movement of the  telescope4    #c4  
,freedom from periodic or other errors  
in driving and smoothness and  freedom  
from 8backlash0 in slow motions4    #d4 
,ease1 speed and accuracy with which    
settings can be made due to  careful    
design and original features in setting 
motors and setting  circles4    #e4     
,great stiffness of tube and            
improvements in method of attaching and 
changing secondary mirrors4    #f4      
,beauty and harmony of design and       
appearance4          ,,section          
#d4--,,optical ,,parts ,,and            
,,spectrographs      ,the ,principal    
,mirror    ,the great mirror is composed
 of hard plate glass cast in one piece  
and  after annealing1 ground and        
polished to the correct shape4 ,as      
received  from the ,st4 ,gobain ,co41   

the disc was #gce inches diameter1 over 
#ac  inches thick with a central hole   
about #f inches diameter and weighed    
nearly #e1jjj pounds4 ,it was first of  
all ground truly circular to a  diameter
 of #gc inches and flat on both sides to
 a thickness of slightly  over #ab      
inches1 while the central hole was      
enlarged to #aj inches4 ,when  the back 
was polished approximately flat1 the    
disc was seen to be a  beautiful        
specimen of the glass makers art1       
homogeneous and almost  entirely free   
from bubbles or other defects4          
,illustration3 ,fig4 #d4--,,photograph  
,,of ,,ring ,,nebula ,,in ,,lyra        
7,enlarged #h diameters7    ,it was now 
ready for the second stage of the       
operation the grinding  of the correct  
shape for the upper reflecting surface4 
,in order to  bring the light of a star 
to an accurate focus this surface must  
be a paraboloid of revolution1 the same 
kind of curve given to the  reflectors  
of search lights or automobile          

headlights4 ,the curve for  this        
reflector of #cj feet focus is very     
nearly a section of a sphere of  #fj    
feet radius1 within one-thousandth of an
 inch1 and consequently  would nearly   
fit a huge globe #abj feet in diameter4 
,the upper surface  of the disc was fine
 ground and polished to this spherical  
surface and  was then ready for the     
final stage1 the 8figuring0 a           
continuation of  the polishing process  
until the centre is deepened about a    
thousandth  of an inch and the surface  
becomes accurately paraboloidal4 ,this  
8figuring10 an exceedingly delicate and 
difficult process especially  over such 
a large surface as the #gb-;inch1 with  
the added difficulty of  a central hole1
 occupied about two years and was not   
completed until  nearly a year and a    
half after the mounting was ready4 ,when
 it is  remembered1 however1 that the   
surface nowhere deviates from the true  
theoretical form more than one          
four-hundred-thousandth of an inch and  

that if one part is accidentally        
polished too deep1 the whole surface    
has again to be brought down to this    
level1 the exceeding delicacy of  the   
operation is evident and the time taken 
not excessive4    ,accurate quantitative
 tests showed that the final figure is  
of the  highest order of accuracy and   
this is further clearly shown by the    
practical test of direct photographs at 
the principal focus4 ,figure  #d1 a six 
fold enlargement of a photograph at the 
principal focus1 of  the ,ring ,nebula  
in ,lyra shows how sharp and small are  
the star images4  ,actual measurement on
 the original negative gives a minimum  
diameter  of two one-thousandths of an  
inch equivalent to only a second of arc 
at the focus4 ,as the images are        
enlarged considerably by unsteadiness   
of the air and errors in guiding the    
star light reflected from the  whole    
surface of the mirror is collected into 
a little disc less than a  thousandth of
 an inch in diameter indicating the     

extraordinary accuracy  of the          
reflecting surface4 ,mr4 ,j4 ,b4        
,mc,dowell1 head of the firm since  ,dr4
 ,brashear's death1 and ,mr4 ,fred      
,hegemann1 his chief optician1 are  to  
be highly congratulated on the          
perfection of figure obtained under     
specially difficult circumstances4      
,further the fine rendering of the      
detail in the ring and the strength of  
the two bands in the interior  indicate 
not only perfect figure but             
exceptionally high polish4              
,mounting of ,mirror    ,this mirror1 to
 maintain its accuracy1 not only        
requires careful  mounting in its cell  
but also protection against temperature 
changes4  ,even though #ab inches thick 
it would bend under its own weight of   
#d1cjj  lbs4 sufficiently to affect the 
figure and consequently it is supported 
in the cell by a specially              
counterweighted lever system so that it 
is  equably supported at twelve points  
and there is no tendency to bend4  ,a   

similar lever support system around the 
edge prevents distortion  due to        
constraint when it is tipped from the   
horizontal position at  different       
positions of the tube4 ,temperature     
changes can produce much  greater       
distortion than flexure but ,victoria   
has the advantage of very  low diurnal  
range and the temperature change around 
the mirror is made  very small by a     
lagging of cotton felt about #b inches  
thick all round  the sides of the closed
 section of the tube1 laced on with a   
duck  cover 7compare ,fig4 #c with ,fig4
 #b7 and an equal thickness below and   
around the edge of the mirror4 ,by this 
lagging the temperature rise in  the    
day-time is only about half a degree    
while the dome temperature  increases   
five degrees1 hence the figure of the   
mirror remains good  whatever the       
temperature changes outside4      ,the  
,principal ,focus    ,as already        
indicated1 the principal mirror when    
used alone forms an  image of the star  

#cj feet above1 at the centre of the    
upper end of  the tube1 and an eyepiece 
could be placed there for visual work or
 a  photographic plate for direct       
photographs of nebulae1 etc4 ,however1  
it  is generally more convenient to use 
a flat mirror at #de forming the  image 
at the side of the tube for photographs 
and so the telescope is  only used in   
this form with a small spectrograph for 
the ultra-violet  region of star        
spectra4 ,the course of the parallel    
beam of light from  the star to its     
image on the slit of the spectrograph is
 graphically  shown in ,fig4 #e ,a and  
also its passage through the slit prisms
 and  lenses of the spectrograph4 ,the  
position of the star image on the slit  
of the spectrograph can be observed by a
 guiding telescope extending  to the    
edge of the tube and can be kept central
 by the portable  aluminium switchboard 
already described4 ,the elevating       
platform is of  course used in work in  
this position4      ,the ,newtonian     

,arrangement    ,for direct photography 
or visual observations at the focus of  
the  #gb-;inch mirror1 the reflected    
cone of star light from the mirror ,b1  
,fig4 #e1 is intercepted by a plane     
mirror also silvered on the front       
surface1 #aie inches diameter and #cbe  
inches thick placed at #de4 ,this  form 
of reflecting telescope was first used  
by ,newton1 hence the name4  ,the focus 
is then formed1 as shown1 at the side of
 the tube1 and if a  plate is placed    
there and accurately guided by small    
eyepieces with  cross wires1 photographs
 of any desired small region in the sky 
can be  obtained1 ,fig4 #d being made in
 this position1 or visual observations  
may be made4 ,the oculars can easily be 
reached from the observing  platform for
 any position of the telescope4         
,the ,cassegrain ,arrangement    ,the   
most generally useful arrangement of the
 #gb-;inch telescope is1  however1 the  
,cassegrain form1 so called from the    
,french astronomer who  first used it4  

,about #g feet below the focus1 the     
conical reflected  pencil from the      
#gb-;inch mirror is intercepted by a    
convex mirror of  the same size as the  
,newtonian and of about #aj feet focal  
length as  seen in ,c1 ,fig4 #e1 and    
also shown in ,fig4 #b and #c4 ,this    
mirror turns  the light downward and1   
after passing through the central hole1 
forms  the image of the star about two  
feet below the mirror surface on the    
slit of the spectrograph or on a visual 
attachment as shown4 ,the  significant  
property of this combination is that the
 focal length is  increased from #cj to 
#ajh feet without changing the tube     
length in a  somewhat similar manner to 
the action of a telephoto lens4 ,it has 
the  same size of image and magnifying  
power as a refractor with a tube #ajh   
feet long and has the decided advantage 
of a much shorter tube and  smaller     
dome4 ,observations with this           
arrangement are made at the lower  end  
of the tube from the observing floor and

 with much greater ease  and convenience
 than at the upper end4 ,changes from   
the ,cassegrain to  the ,newtonian or   
,principal ,focus arrangements are      
readily effected by  a device due to the
 genius of ,mr4 ,swasey whereby only the
 mirrors and  attaching tubes require to
 be handled1 instead of the whole upper 
end  of the tube as in previous         
reflectors4    ,illustration3 ,fig4     
#e4--;,,course ,,of ,,light ,,in        
,,telescope ,,from ,,star ,,to ,,focus  
,accessory ,optical ,parts    ,a full   
set of eyepieces giving magnifying      
powers from #abj to #e1jjj  diameters   
and a complete double-slide plate holder
 with guiding  eyepieces for direct     
photography at the ,newtonian focus are 
provided4  ,in addition there is a      
visual attachment shown in diagram ,c1  
,fig4 #e1  which enables the telescope  
to be used visually at the ,cassegrain  
focus  without removing the             
spectrograph4 ,there are three finders  
attached  to the telescope tube for     

picking up and centering the stars4 ,two
 of  #d inch aperture and #e feet focus1
 of power about #ej1 one north1 one     
south on the tube1 and a long focus     
tubeless finder with a lens of #g  inch 
aperture and #cj feet focus at the top  
of the telescope tube and an  ocular of 
power #bjj at the bottom4      ,the     
,spectrographs    ,most of the          
astronomical work with the #gb-;inch    
telescope is  spectroscopic1            
photographing the spectra of the stars1 
and so a  description of the principles 
and operation of spectrographs is       
desirable4 ,stellar spectrographs have  
evolved into certain definite  forms and
 the two spectrographs for the #gb-;inch
 telescope are examples  of the most    
recent types4 ,in essence a spectrograph
 consists of a  narrow slit1 one or     
two-thousandths of an inch wide1 on     
which the  star light is focussed4 ,that
 passing through the slit falls on the  
collimator lens which makes it parallel 
and then on a prism or prisms1          

triangular shaped pieces of glass which 
change the direction of the  light and  
decompose it1 breaking it up into its   
constituent rainbow  colours4 ,the      
spectrum1 as it is called1 is focussed  
by a camera lens on  a photographic     
plate or can be viewed by a small       
telescope if desired4  ,the course of   
the star light from the slit through    
collimator1 prism  and camera lens to   
the plate is shown in ,c1 ,fig4 #e1     
while a view of the  ,cassegrain        
spectrograph showing the interior       
mechanism and accessories  is given in  
,fig4 #f4 ,the part of the spectrum     
photographed is usually  only the blue  
and violet region to which the ordinary 
plate is most  sensitive1 and obviously 
no colours appear on the negative but   
only a  narrow dark strip which is      
crossed by light or dark lines4 ,it is  
from  the number and position of these  
lines that we obtain such a remarkable  
amount of information about the physical
 and chemical constitution1 the         

temperature1 motion and distance of the 
stars4 ,the length of the star  spectrum
 photographed with one prism is about   
one and a third inches1  twice and three
 times that with two and three prisms4  
,its width is  about one-hundredth of an
 inch and in order to make it this wide 
the  star image has to be moved back and
 forward along the slit4 ,the length  of
 spectrum with the ultra-violet         
spectrograph1 which only differs from   
the other in the prisms and lenses      
allowing the spectrum below the  violet 
to pass1 is about one inch4 ,a          
photograph of the spectrum of iron  or  
brass is made beside the star spectrum  
to serve as a standard to  determine the
 positions of the star lines4           
,illustration3 ,fig4 #f4--,,stellar     
,,spectrograph ,,arranged ,,for ,,use   
,,with ,,one  ,,prism    7,,temperature 
,,case ,,removed7      ,method of ,use  
,every terrestrial element gives groups 
of lines in certain positions  in the   
spectrum and if we find similar groups  

in the star spectrum  we are sure this  
element is present in the star4 ,further
 if we find  these lines are displaced  
to red or violet of their normal        
position  we know that the star is      
receding from or approaching to us4     
,with  the one-prism spectrograph a     
speed of one mile per second means a    
displacement of the lines of one        
thirty-thousandth of an inch4 ,thus  if 
the lines are shifted to the violet by a
 thousandth of an inch1  the star is    
approaching the earth with a speed of   
#cj miles a second4  ,these             
displacements are accurately measured by
 a microscope and the  measurement of   
the radial velocities of the stars is   
one of the main  researches of this     
observatory4 ,obviously with such small 
displacements  to be measured the       
greatest care must be taken to avoid all
 sources  of error4 ,the spectrograph   
must be exceptionally rigid to avoid    
differential bending as it moves with   
the telescope4 ,as change of            

temperature can produce spurious shifts 
of the lines1 the temperature  must be  
kept as constant as possible1 this being
 effected here by  a very accurate      
electrical thermostatic device called   
the ,calendar  ,recorder which maintains
 the temperature constant to            
one-hundredth of  a degree4 ,the optical
 parts must be of the highest quality to
 give  perfect definition to the        
spectrum lines and many other           
precautions  must be taken if accurate  
work is desired4 ,the spectrographs of  
the  #gb-;inch telescope have unequalled
 defining power and are the last word   
in convenience of manipulation and      
accuracy of work4    ,owing to the      
faintness of the star light and to its  
being spread out  into a spectrum a     
considerable time is required to        
photograph the  spectrum of a star1     
about #bj minutes for the sixth         
magnitude1 the limit  of visibility to  
the unaided eye1 when photographed with 
one prism1  while three prisms will take

 nearly five times as long4 ,hence the  
necessity and use of large telescopes is
 not to get high magnifying  power but  
to collect sufficient light from the    
fainter stars to enable  their spectra  
to be photographed or other observations
 made4          ,,section #e4--,,the    
,,work ,,of ,,the ,,telescope           
,prevalent ,misconceptions    ,the      
general idea of an astronomer's work1 as
 gathered from the  questions and       
remarks of visitors1 is that he sits at 
the eyepiece of  the telescope sweeping 
the heavens in a search for new planets1
 comets  or stars4 ,the absolute        
futility of such a use of the telescope 
is  evident when it is realized that the
 main field of the #gb-;inch covers     
only about one hundred-millionth of the 
sky and if only five seconds  was       
required to examine each field it would 
take more than a lifetime  to go over   
the whole sky once4 ,a second           
misconception is the idea that  large   
telescopes are used for visual          

observations of the planets with        
special reference to their habitability4
 ,no work is being attempted  at this or
 other large observatories on planetary 
detail for which  about an #ah-;inch    
refractor gives the best results and    
such a large  telescope as the #gb-;inch
 is quite unsuited4 ,all scientific     
observations  with the #gb-;inch are    
made photographically and it is only    
arranged for  visual use on ,saturday   
evenings when for two hours visitors are
 allowed  to observe the heavenly       
bodies4 ,a third misconception is that  
the  astronomer only works at night4    
,however true this idea may have been   
in the days of visual observations when 
the measurements were made at  the      
eyepiece1 there is certainly now1 when  
photography is so generally  applied1   
more day than night work in astronomy4  
,besides the advantages  of permanency1 
accuracy of measurement and power of    
recording objects  beyond the range of  
the keenest eyesight1 the photographic  

method has  the further great advantage 
that an hour's exposure may give        
sufficient  material for several days'  
measurement and discussion4             
,spectroscopic ,work    ,as already     
indicated most of the work with the     
#gb-;inch telescope  is spectroscopic1  
but as also indicated modern            
spectroscopic  investigations cover so  
wide a range of research that the actual
 work  of the observatory is very       
varied4 ,by aid of suitable             
spectrographs  attached to a large      
telescope we can measure the speed of   
the stars  towards or from us1 their    
radial velocity as it is termed4 ,we can
  discover double stars too close ever  
to be seen double in any telescope  and 
we can determine the manner in which    
they revolve around one  another and    
their distance apart and mass4 ,from the
 spectra of the  stars we can determine 
their absolute brightness as compared   
with the  sun and their parallax or     
distance4 ,the chemical elements present

 in  the outer atmospheres of the stars 
can be determined and the pressure  in  
these atmospheres4 ,the measurement of  
temperatures and other  physical        
conditions in the stars by means of the 
spectroscope is now  an accomplished    
fact and one of the most recent         
developments of the  spectroscopic work 
here has been to provide evidence of the
 truth of  a theory of atomic structure 
and to show that the atomic constants in
  the enormous furnaces of the stars are
 the same as on the earth4 ,such  a     
catalogue of information1 obtained from 
an investigation of the mere  quality of
 the light from stars so faint as to be 
quite invisible to  the unaided eye and 
so distant that it may take thousands of
 years  to travel to us1 is sufficiently
 comprehensive to be treated in more    
detail4      ,radial ,velocities        
,when the #gb-;inch telescope was in    
course of design and construction1  one 
of the greatest needs in astronomical   
work was increased data in  regard to   

the radial velocities of the stars4     
,although the telescope  was so designed
 as to be suitable for all kinds of     
observational  work1 special attention  
was devoted to the spectroscopic end4   
,after  consultation with the most      
prominent astronomers an observing      
programme  of about #hjj stars whose    
8proper0 or cross motions across the sky
 were  accurately known but whose radial
 velocities had not been determined1    
was prepared and spectroscopic          
observations of the stars on this       
programme were commenced as soon as the 
telescope was completed in  ,may #aiah4 
,after slightly over three years' work1 
observation and  measurement were       
completed and ,vol4 ,,ii1 ,no4 #a of the
 observatory  publications1 8,the       
,radial ,velocities of #eid ,stars10 was
 published early  in #aibb4 ,as hitherto
 the radial velocities of only about    
#b1jjj stars  had been obtained1 this   
work was a considerable addition to     
existing  data about the motions of the 

stars and will be of great use in       
extending our knowledge of the structure
 and motions of the universe4  ,a second
 programme of #a1ejj stars has been     
prepared but owing to other  intervening
 observational work1 not much has yet   
been done on this new  programme4       
,one of the auxiliary programmes        
undertaken and nearly completed since   
the first programme is the determination
 of the radial velocities of a  very    
interesting but limited class of stars1 
the highest temperature  stars known1   
the ,o-type stars4 ,the radial          
velocities and other  interesting data  
about #ej of these stars have been      
completed4      ,spectroscopic ,double  
,stars    ,in the measurement of the    
radial velocity of the #hjj stars on the
  first programme it was found that in  
about #ahj stars successive plates  did 
not give constant velocities1 the stars 
at one time approaching  at another     
receding from us4 ,this phenomenon is   
practically certain  proof that we are  

measuring the velocity of a star        
revolving around an  invisible companion
 and such stars are generally called    
spectroscopic  binaries to distinguish  
them from visual binaries which can be  
seen  double in the telescope4 ,over    
#bjj spectroscopic binaries have been   
discovered at this observatory as       
compared with about #gjj discovered     
elsewhere1 again a considerable         
addition4 ,in about #bj of these        
binaries1 observations were continued   
until the period of revolution1  the    
form of the orbit1 the separation of the
 two stars and in some  cases1 their    
masses were determined4 ,in a particular
 class of  spectroscopic binaries1 the  
eclipsing variables1 which allow from   
the  combination of spectroscopic and   
photometric measurements the absolute   
dimensions to be obtained1 we were able 
to determine the separation of  the two 
stars1 their diameters1 densities1      
masses and brightnesses and  the        
probable distances4 ,such complete      

information has been obtained  here     
about seven systems1 while only seven   
other systems have been  determined     
elsewhere4      ,absolute ,magnitude and
 ,distance    ,a new application of     
spectroscopic methods is to the         
determination of  the total brightness  
of the stars as compared with the sun   
and their  distance or 8spectroscopic   
parallax0 as it is called4 ,this depends
 not  on the positions but on the       
relative intensity or strength of the   
lines  in the spectra of the stars and  
has only been developed in the last     
three or four years4 ,the absolute      
magnitude and spectroscopic parallax  of
 about #hjj stars is now nearly         
completed and will soon be published    
while as a side line the radial         
velocities of #abe more stars have been 
determined4      ,physical ,conditions  
in the ,stars    ,the spectrographs have
 also been used by one member of the    
staff in  the determination of the      
physical and chemical conditions in     

stellar  atmospheres1 a new and         
difficult problem but one which promises
 not  only very valuable additions to   
our knowledge of the constitution of    
the stars but may also lead to economic 
applications of the greatest            
importance4 ,a new method depending upon
 the use of a wedge of dark  glass has  
been applied to determining the         
distribution of energy in the  different
 parts of the spectrum of the stars and 
to measuring their  temperatures1 while 
an application of the same methods to   
individual  lines may lead to a great   
increase in our knowledge of conditions 
in  the stars4 ,a special investigation 
of three of the high temperature        
,o-type stars referred to above has     
proved the existence in the spectra  of 
these stars of lines predicted as       
present from purely theoretical         
conditions but never previously         
identified and has thus remarkably      
verified a theory of the structure of   
the atom4 ,the measurement of the  wave 

lengths of these hitherto unknown lines 
has led to an important  independent    
determination of the fundamental        
constants of atomic  structure and the  
dimensions of the atom and has shown    
that these  constants and dimensions are
 the same in the tremendous furnaces of 
the stars as in our terrestrial         
laboratories1 a verification of the     
homogeneity of matter and the uniformity
 of physical laws throughout  the       
universe4 ,further interesting results  
from this investigation  are the        
application of a new theory of          
ionization with the probable  relative  
abundance of the elements to an         
independent determination of  the       
temperature of these stars4      ,other 
,investigations    ,direct photographs  
have been made of some nebulae and      
clusters but  this work is not being    
definitely followed at present4         
,investigations  into the phenomena     
accompanying some short period binaries 
have been  made and into the behaviour  

of the two strong calcium lines ,h and  
,k  in the spectra of the high          
temperature stars from which interesting
  and valuable results are expected4    
,since the observatory commenced  work  
two bright novae or new stars have      
appeared1 which have been  fully        
observed spectroscopically here and the 
results discussed4 ,the  plates of the  
nova in ,aquila have been loaned to the 
observatory at the  ,university of      
,cambridge1 ,england1 for fuller        
discussion and analysis4      ,value of 
,astronomical ,work    ,this brief      
sketch of the work of the observatory   
naturally leads to  the question        
frequently asked of astronomers3--,what 
use is the work  done at observatories  
and what practical value can a knowledge
 of the  stars have in everyday life8   
,while astronomy has obvious practical  
applications to navigation and surveying
 yet nine-tenths of modern  astronomical
 research is devoted to the more or less
 abstract question  of the constitution 

and motion of the stars and the         
structure of the  universe4 ,indeed most
 physical and chemical as well as       
astronomical  research is undertaken for
 the purpose of increasing our knowledge
  and of investigating the secrets and  
laws of nature and has generally  no    
direct practical economic application4  
,but it is now generally  recognized by 
the layman as well as the scientist that
 without abstract  there can be no      
applied science and that all the great  
economic and  industrial applications of
 science have had to be preceded by the 
abstract and apparently non-practical   
investigations of pure science4  ,the   
,great ,war perhaps made more evident   
than ever before the absolute           
dependence of applied science upon the  
unselfish and abstract work of  pure    
science4      ,economic ,value    ,in   
view of past experience in science it   
would hence be a rash  prediction to    
assert that the investigation of the    
conditions in  distant stars can have no

 practical application upon earth4 ,it  
may be  of interest to point out one    
possible application of astrophysical   
research4    ,it is generally agreed    
that one of the most important economic 
problems of the not far distant future  
will be the provision of  sources of    
energy to replace our rapidly depleting 
supplies of coal  and oil4 ,it appears  
now that the most probable solution of  
this  problem will consist in the       
development of some method for utilizing
  the inexhaustible stores of energy    
contained in the atoms of matter4       
,modern research on conditions in the   
stars has made it practically  certain  
that the enormous supply of energy1     
which has been radiated  into space for 
aeons of time from these bodies1 can    
only be maintained  undiminished by the 
energy released by the transformation of
 atoms  in the interior of the stars1   
where conditions of temperature and     
pressure prevail at present unattainable
 in terrestrial laboratories4  ,the most

 hopeful line of attack upon this       
tremendously important  economic problem
 hence seems to lie in the systematic   
astrophysical  investigation of         
conditions in the stars supplemented by 
physical and  chemical researches on the
 structure of the atom4      ,ethical   
,value    ,while astronomers and        
scientific men generally fully realize  
the value  of the practical applications
 of science1 their main purpose is the  
search for truth and the extension of   
our knowledge of nature4 ,while it  is  
possible that investigation of the stars
 may have immense economic  value1 it is
 certain that it has tremendous ethical 
value giving us a  clearer knowledge of 
the laws of nature and of our relations 
to the  wonders of creation4 ,astronomy 
is the oldest and in many respects the  
most important of the sciences and its  
study1 through the ages has  been one of
 the most elevating influences on human 
character4 ,poincar  has well said that 
if the earth had been so continuously   

covered with  clouds that the heavenly  
bodies could not be seen1 mankind would 
still  be in a primitive state and under
 the domain of superstition4 ,the main  
superiority of modern over ancient      
civilization does not consist in the    
greater abundance of the necessities and
 luxuries of life1 although  this is    
undoubtedly due primarily to scientific 
research1 but to the  elevating         
influences of the truer conceptions of  
nature made possible  by the abstract   
study of astronomy and other sciences4  
,it has been truly said that the degree 
of civilization of a country may  be    
judged by the support it gives to the   
study of astronomy4 ,by the             
establishment and maintenance of the    
,dominion ,observatory at ,ottawa  and  
of the ,dominion ,astrophysical         
,observatory at ,victoria with the      
second largest telescope in the world1  
,canada has a just claim on this        
criterion to the favourable estimation  
of the scientific world4                

,,victoria1 ,b4,c41    ,may1 #aibc4     
,,transcriber',s ,,notes3               
,italicized text is surrounded by       
underscores3 italics4      ,obvious     
typographical errors have been          
corrected4