----------------------------------------
----------------------------------------
--------------------------              
,transcrib]'s note3                     
,words 9 ,italic are enclos$ betwe5     
und]scores4                             
----------------------------------------
----------------------------------------
--------------------------     ,,!      
,,sid]eal ,,mess5g]       ,,riv+tons    
,london      ,wat]loo ,place      ,ox=d 
,magdal5 ,/reet      ,cambridge         
,tr9ity ,/reet   ,illu/ration3          
,,galileo',s ,,brok5 ,,l5s4  ,,exhibit$ 
,,9 ,,! ,,loan ,,collection ,,(         
,,sci5tific ,,app>atus ,,at ,,! ,,s\?   
,,k5s+ton ,,museum1 #ahgf4  ,f a        
photograph ( ! ,sci5ce & ,art ,dep>tm5t1
 ,s\? ,k5s+ton4         ,,! ,,sid]eal   
,,mess5g]      ,,(      ,,galileo       
,,galilei      ,,& ,a ,,"p ,,( ,,!      
,,preface ,,to ,,kepl]',s ,,dioptrics   
,,conta9+ ,,! ,,orig9al ,,acc\nt ,,(    
,,galileo',s     ,,a/ronomical          
,,discov]ies4      ,a ,translation )    

,introduction & ,notes      ,,by        
,,edw>d ,,/af=d ,,c>los1 ,m4,a4         
,,head ,,ma!matical ,,ma/] ,,9 ,,*ri/',s
 ,,hospital4      ,,riv+tons            
,,wat]loo ,,place1 ,,london     ,ox=d & 
,cambridge     ,,mdccclxxx              
,,prefatory ,,note4   ,ab\t five ye>s   
ago ,i 0 engag$ 9 prep>+ a catalogue ( !
 anci5t books :i* belong to ,*ri/'s     
,hospital4 ,"o portion ( ^! books       
consi/$ ( a collection ( anci5t         
ma!matical works pres5t$ at v>i\s times 
= ! use ( t "p ( ! s*ool :i* is kn[n z !
 ,royal ,ma!matical ,f\ndation ( ,k+    
,*>les ,,ii4 ,among/ !m 7 "s well kn[n  
by "n to e ma!matical /ud5t1 b :i* few h
 ev] se54 ,p]haps ! mo/ int]e/+ ( !m all
 0 a little volume1 pr9t$ 9 ,london 9   
#afec1 conta9+ ,gass5di's ,explanation (
 ! ,ptolemaic & ,cop]nican ,sy/ems (    
,a/ronomy1 z well z t ( ,ty*o ,brahe1   
,galileo's ,sid]eus ,nuncius1 & ,kepl]'s
 ,dioptrics4 ,i f\nd ,galileo's acc\nt (
 8 a/ronomical discov]ies s int]e/+1 bo?
 9 matt] & 9 /yle1 t ,i translat$ x z a 

recreation f s*ool-"w4 ,i v5ture to ?9k 
t o!rs also w be int]e/$ 9 foll[+       
,galileo ?r\gh ! appreh5sion ( 8 fam\s  
discov]ies1 & 9 read+ ! language 9 :i*  
he ann\nc$ !m4     ,,introduction4   ,9 
#afji1 ,galileo1 !n ,pr(essor (         
,ma!matics at ,padua1 9 ! s]vice ( !    
,v5etian ,republic1 he>d f a            
correspond5t at ,p>is ( ! inv5tion ( a  
telescope1 & set to "w to consid] h[ su*
 an in/rum5t c\ld be made4 ,! result 0 8
 inv5tion ( ! telescope kn[n by 8 "n1 & 
id5tical 9 pr9ciple ) ! mod]n           
op]a-glass4 ,9 a m>itime & w>like ,/ate1
 ! advantages to be expect$ f su* an    
inv5tion 7 imm$iately recognis$1 &      
,galileo 0 rew>d$ ) a confirmation ( 8  
,pr(essor%ip = life1 & a h&some /ip5d1 9
 recognition ( 8 inv5tion & con/ruction 
( ! fir/ telescope se5 at ,v5ice4 ,9 8  
pamphlet1 ,! ,sid]eal ,mess5g]1 "h      
translat$1 ,galileo relates h[ he came  
to le>n ! value ( ! telescope =         
a/ronomical rese>*2 & h[ 8 obs]vations 7
 rew>d$ by num]\s discov]ies 9 rapid    

succession1 & at l5g? by t ( ,jupit]'s  
satellites4 ,galileo at once saw ! value
 ( ?is discov]y z be>+ ^u ! e/abli%m5t (
 ! ,cop]nican sy/em ( a/ronomy1 :i* _h  
met ) slight acceptance1 & inde$ z yet  
_h h>dly any recomm5dation except t (   
great] simplicity4 ,kepl] _h j publi%$  
at ,prague 8 "w on ! planet ,m>s        
7,comm5t>ia de motibus ,/ell ,m>tis71 on
 :i* he _h be5 engag$ app>5tly = eight  
ye>s2 !re he he>d ( ,galileo's          
discov]ies1 & at l5g? 0 invit$ by       
,galileo himself1 ?r\gh a common fri5d1 
,giuliano de' ,m$ici1 ambassador ( !    
,gr&-,duke ( ,tuscany1 ,cosmo de' ,m$ici
 ,,ii41 to ! ,emp]or ,rudolph ,,ii41 to 
correspond ) ,galileo on ! subject ( ^! 
discov]ies4 ,! ,emp]or also reque/$ 8   
op9ion1 & ,kepl] accord+ly exam9$       
,galileo's ,sid]eal ,mess5g] 9 a        
pamphlet1 entitl$ ,a ,discussion ) !    
,sid]eal ,mess5g] 7,flor5ce1 #afaj74  ,9
 ?is ,discussion ,kepl] gives reasons = 
accept+ ,galileo's obs]vations--al?\gh  
he 0 n able to v]ify !m f want ( a      

telescope--& entirely supports          
,galileo's views & conclusions1 adduc+ 8
 own previ\s speculations1 or po9t+ out1
 z 9 ! case ( ,galileo's idea (         
e>?-light on ! moon1 ! previ\s          
conception ( ! same explanation ( !     
ph5om5on4 ,he rejects1 h[ev]1 ,galileo's
 explanation ( ! copp] col\r ( ! moon 9 
eclipses4 ,kepl] ends by express+       
unb\nd$ en?usiasm at ! discov]y (       
,jupit]'s satellites1 & ! argum5t x     
furni%es 9 support ( ! ,cop]nican !ory4 
,soon aft]1 9 #afaa1 ,kepl] publi%$     
ano!r pamphlet1 8 ,n>rative1 giv+ an    
acc\nt ( actual obs]vations made 9      
v]ification ( ,galileo's discov]ies by  
himself & sev]al fri5ds1 ^: names he    
gives1 ) a telescope made by ,galileo1 &
 belong+ to ,erne/1 ,elector & ,ar*bi%op
 ( ,cologne4 ,kepl] & 8 fri5ds saw !    
lun> m\nta9s & ?ree ( ! satellites (    
,jupit]1 b fail$ to make out any signs (
 ! r+ ( ,saturn correspond+ to !        
imp]fect description ( ,galileo4  ,kepl]
 _h previ\sly publi%$ a treatise on     

,optics 7,frank=t1 #afjd74 ,he n[ ext5d$
 x to ! consid]ation ( ! !ory ( !       
telescope1 & expla9$ ! pr9ciple (       
,galileo's telescope2 he also %[$ ano!r 
comb9ation ( l5ses :i* w\ld produce a   
simil> effect4 ,?is 0 ! pr9ciple ( !    
common a/ronomical telescope1 (t5 call$1
 f ?is circum/ance1 ,kepl]'s telescope1 
?\gh he did n con/ruct x4 ,! acc\nt (   
,galileo's lat] a/ronomical discov]ies (
 ,saturn's r+ & ! phases ( ,v5us is tak5
 f ! preface ( ?is "w4--7,kepl]'s       
,dioptrics2 ,augsburg1 #afaa47  ,9 #afab
 ,galileo publi%$ a s]ies ( obs]vations 
( sol> spots1 & 9 #afah "s obs]vations (
 ?ree comets4 ,!re exi/ also long s]ies 
( m9ute obs]vations ( ,jupit] & 8       
satellites1 cont9u$ to ,novemb]         
#afai4--7;,galileo's ,works2 ,flor5ce1  
#ahde47  ,fur!r a/ronomical rese>*es may
 h be5 h9d]$ by fail+ sight4 ,"o m      
a/ronomical discov]y1 h[ev]1 t ( !      
moon's librations1 0 made z late z      
#afcg1 & ! ann\ncem5t ( x is dat$ 8dalla
 mia c>c]e di ,arcetri40 ,galileo di$   

,janu>y #h1 #afdb4   ,! foll[+ editions 
h be5 us$ = ! translation3--  ,galileo's
 ,works4      #a4  ,flor5ce1 #agah4     
#b4  ,padua1 #agdd4     #c4  ,flor5ce1  
#ahdb-ef4   ,sid]eus ,nuncius4      #a4 
,v5ice1 #afaj4     #b4  ,london1 #afec4 
,kepl]'s ,works1 ed4 ,c4 ,fris*4        
,frankfurt a4 ,m41 #aheh-ga4            
,prodromus diss]tationum ma!matic>um    
cont95s ,my/]ium     ,cosmographicum de 
admirabili proportione orbium cle/ium4  
,tb+51 #aeif4      ,a/ronomia nova      
7,comm5t>ia de motibus /ell     ,m>tis74
 ,prague1 #afji4         ,,!            
,,sid]eal ,,mess5g]      ,,(            
,,galileo ,,galilei         ,,!         
,,sid]eal ,,mess5g]      ,,unfold+      
,,great ,,& ,,m>vell\s ,,sights1 ,,&    
,,propos+ ,,!m ,,to     ,,! ,,att5tion  
,,( ,,e ,,"o1 ,,b ,,especially          
,,philosoph]s ,,&     ,,a/ronom]s1      
,,be+ ,,su* ,,z ,,h ,,be5 ,,obs]v$ ,,by 
,,galileo ,,galilei      ,a ,,g5tleman  
,,( ,,flor5ce1 ,,pr(essor ,,(           
,,ma!matics ,,9 ,,! ,,univ]sity     ,,( 

,,padua1      ,,) ,,! ,,aid ,,( ,a      
,,telescope      lately inv5t$ by him1  
,respect+ ! ,moon's ,surface1 an        
innum]able numb] ( ,fix$     ,/>s1 !    
,milky ,way1 & ,nebul\s ,/>s1 b         
especially respect+     ,f\r ,planets   
:i* revolve r\nd ! ,planet ,jupit] at   
diff]5t     di/ances & 9 diff]5t p]iodic
 times1 ) amaz+ velocity1     & :i*1    
aft] rema9+ unkn[n to e "o up to ?is    
day1 !     ,au?or rec5tly discov]$1 &   
det]m9$ to "n !      ,,m$icean ,,/>s4   
,v5ice #afaj4   ,,to ,,! ,,mo/ ,,s]5e   
,,cosmo ,,de' ,,m$ici1 ,,! ,,second1    
,,f\r? ,,gr&-,,duke ,,( ,,tuscany4      
,!re is c]ta9ly some?+ v noble &        
l>ge-m9d$ 9 ! int5tion ( ^? :o h        
endeav\r$ to protect f envy ! noble     
a*ievem5ts ( di/+ui%$ m51 & to rescue _!
 names1 wor?y ( immortality1 f oblivion 
& decay4 ,?is desire has giv5 u !       
l9eam5ts ( fam\s m51 sculptur$ 9 m>ble1 
or fa%ion$ 9 bronze1 z a memorial ( !m  
to future ages2 to ! same feel+ we owe !
 erection ( /atues1 bo? ord9>y &        

eque/rian2 h5ce1 z ! poet#a says1 has   
orig9at$ exp5diture1 m\nt+ to ! />s1 ^u 
columns & pyramids2 ) ?is desire1 la/ly1
 cities h be5 built1 & di/+ui%$ by !    
names ( ^? m51 :om ! gratitude ( po/]ity
 ?\ght wor?y ( be+ h&$ d[n to all ages4 
,= ! /ate ( ! human m9d is su*1 t unless
 x be cont9ually /irr$ by ! c\nt]p>ts#b 
( matt]s1 obtrud+ !mselves ^u x f )\t1  
all recollection ( ! matt]s easily      
passes away f x4      #a ,prop]tius1    
iii4 #b4 #ag-bb4      #b ,comp>e        
,lucretius iv4 #hha3      ,dico animo   
no/ro primum simulacra me&i ,accid]e1   
atque animum     puls>e4  ,b o!rs1 hav+ 
reg>d = m /able & m la/+ monum5ts1      
secur$ ! et]nity ( ! fame ( great m5 by 
plac+ x "u ! protection1 n ( m>ble or   
bronze1 b ( ! ,muses' gu>dian%ip & !    
imp]i%able monum5ts ( lit]ature4 ,b :y d
 ,i m5tion ^! ?+s1 z if human wit1      
cont5t ) ^! regions1 did n d>e to       
advance fur!r2 :]eas1 s9ce %e well      
und]/ood t all human monum5ts d p]i% at 
la/ by viol5ce1 by wea!r1 or by age1 %e 

took a wid] view1 & inv5t$ m imp]i%able 
signs1 ov] :i* de/roy+ ,"t & envi\s ,age
 c\ld claim no rights2 s1 betak+ h]self 
to ! sky1 %e inscrib$ on ! well-kn[n    
orbs ( ! brighte/ />s--^? ev]la/+       
orbs--! names ( ^? :o1 = em95t & god-l  
de$s1 7 acc\nt$ wor?y to enjoy an       
et]nity 9 company ) ! />s4 ,:]e=e ! fame
 ( ,jupit]1 ,m>s1 ,m]cury1 ,h]cules1 & !
 re/ ( ! h]oes by ^: names ! />s are    
call$1 w n fade until ! ext9ction ( !   
spl5d\r ( ! con/ellations !mselves4  ,b 
?is inv5tion ( human %rewdness1 s       
p>ticul>ly noble & admirable1 has gone  
out ( date ages ago1 inasmu* z primeval 
h]oes are 9 possession ( ^? bright      
abodes1 & keep !m by a sort ( "r2 into  
^: company ! affection ( ,augu/us 9 va9 
attempt$ to introduce ,julius ,cs>2 = :5
 he wi%$ t ! "n ( ! ,julian con/ellation
 %\ld be giv5 to a />1 :i* appe>$ 9 8   
"t1 "o ( ^? :i* ! ,greeks & ! ,lat9s    
alike "n1 f _! hair-l tails1 comets1 x  
vani%$ 9 a %ort "t & mock$ 8 too eag]   
hope4 ,b we are able to read ! heav5s = 

y\r highness1 mo/ ,s]5e ,pr9ce1 f> m    
truly & m happily1 = sc>cely h !        
immortal graces ( y\r m9d begun to %9e  
on e>?1 :5 bright />s pres5t !mselves 9 
! heav5s1 l tongues to tell & celebrate 
y\r mo/ surpass+ virtues to all "t4     
,behold !re=e1 f\r />s res]v$ = y\r     
fam\s "n1 & ^? n belong+ to ! common &  
less conspicu\s multitude ( fix$ />s1 b 
9 ! bright ranks ( ! planets--f\r />s   
:i*1 mov+ diff]5tly f ea* o!r1 r\nd !   
planet ,jupit]1 ! mo/ glori\s ( all !   
planets1 z if !y 7 8 own *ildr51        
accompli% ! c\rses ( _! orbits )        
m>vell\s velocity1 :ile all ! :ile ) "o 
accord !y complete all toge!r mighty    
revolutions e t5 ye>s r\nd ! c5tre ( !  
univ]se1 t is1 r\nd ! ,sun4  ,b ! ,mak] 
( ! ,/>s himself seem$ to direct me by  
cle> reasons to assign ^! new planets to
 ! fam\s "n ( y\r highness 9 pref]5ce to
 all o!rs4 ,= j z ^! />s1 l *ildr5 wor?y
 ( _! sire1 nev] leave ! side ( ,jupit] 
by any appreciable di/ance1 s :o does n 
"k t clem5cy1 k9dness ( he>t1 g5tl5ess (

 mann]s1 spl5d\r ( royal blood1 nobl5ess
 9 public functions1 wide ext5t (       
influ5ce & p[] ov] o!rs1 all ( :i* h    
fix$ _! common abode & seat 9 y\r       
highness1--:o1 ,i say1 does n "k t all  
^! qualities1 accord+ to ! provid5ce (  
,god1 f :om all good ?+s d come1 emanate
 f ! b5ign /> ( ,jupit]8 ,jupit]1       
,jupit]1 ,i ma9ta91 at ! in/ant ( ! bir?
 ( y\r highness hav+ at l5g? em]g$ f !  
turbid mi/s ( ! horizon1 & be+ 9        
possession ( ! middle qu>t] ( ! heav5s1 
& illum9at+ ! ea/]n angle1 f 8 own royal
 h\se1 f t exalt$ ?rone1 look$ out ^u   
y\r mo/ happy bir?1 & p\r$ =? into a mo/
 pure atmosph]e all ! brightness ( 8    
maje/y1 9 ord] t y\r t5d] body & y\r    
m9d--?\gh t 0 already adorn$ by ,god )  
/ill m spl5did graces--might imbibe )   
y\r fir/ brea? ! :ole ( t influ5ce &    
p[]4 ,b :y %\ld ,i use only plausible   
argum5ts :5 ,i c almo/ absolutely       
demon/rate my conclusion8 ,x 0 ! w (    
,almighty ,god t ,i %\ld be judg$ by y\r
 mo/ s]5e p>5ts n unwor?y to be employ$ 

9 tea*+ y\r highness ma!matics1 :i* duty
 ,i dis*>g$1 dur+ ! f\r ye>s j pass$1 at
 t "t ( ! ye> :5 x is cu/om>y to take a 
relaxation f sev]] /udies4 ,:]e=e1 s9ce 
x evid5tly fell to my lot by ,god's w1  
to s]ve y\r highness1 & s to receive !  
rays ( y\r surpass+ clem5cy & b5efic5ce 
9 a position ne> y\r p]son1 :at wond] is
 x if y h s w>m$ my he>t t x ?9ks ab\t  
sc>cely any?+ else day & night1 b h[ ,i1
 :o am inde$ y\r subject n only by      
incl9ation1 b also by my v bir? &       
l9eage1 may be kn[n to be mo/ anxi\s =  
y\r glory1 & mo/ grateful to y8 ,& s1   
inasmu* z "u y\r patronage1 mo/ s]5e    
,cosmo1 ,i h discov]$ ^! />s1 :i* 7     
unkn[n to all a/ronom]s be=e me1 ,i h1 )
 v good "r1 det]m9$ to designate !m ) ! 
mo/ augu/ "n ( y\r family4 ,& z ,i 0 !  
fir/ to inve/igate !m1 :o c rightly     
blame me if ,i give !m a "n1 & call !m !
 ,m$icean ,/>s1 hop+ t z mu*            
consid]ation may accrue to ^! />s f ?is 
title1 z o!r />s h br\ght to o!r h]oes8 
,= n to speak ( y\r mo/ s]5e ance/ors1  

to ^: ev]la/+ glory ! monum5ts ( all    
hi/ory be> witness1 y\r virtue alone1   
mo/ mighty sire1 c conf] on ^? />s an   
immortal "n2 = :o c d\bt t y w n only   
ma9ta9 & pres]ve ! expectations1 high   
?\gh !y be1 ab\t y\rself1 :i* y h ar\s$ 
by ! v happy beg9n+ ( y\r gov]nm5t1 b t 
y w also f> surpass !m1 s t :5 y h      
conqu]$ o!rs l y\rself1 y may /ill vie )
 y\rself1 & become day by day great] ?an
 y\rself & y\r greatness8  ,accept1 !n1 
mo/ clem5t ,pr9ce1 ?is addition to !    
glory ( y\r family1 res]v$ by ! />s = y2
 & may y enjoy = _m ye>s ^? good        
bless+s1 :i* are s5t to y n s mu* f !   
/>s z f ,god1 ! ,mak] & ,gov]nor ( !    
/>s4      ,y\r ,highness's mo/ devot$   
s]vant1      ,galileo ,galilei4         
,padua1 ,m>* #ab1 #afaj4     ,,!        
,,a/ronomical ,,mess5g]       ,conta9+ &
 sett+ =? ,obs]vations lately made ) !  
aid     ( a newly inv5t$ ,telescope     
respect+ ! ,moon's ,surface1 !          
,milky ,way1 ,nebul\s ,/>s1 an          
innum]able multitude ( ,fix$ ,/>s1     &

 also respect+ ,f\r ,planets nev] be=e  
se51 :i* h be5     nam$      ,,!        
,,cosmian ,,/>s4#c      #c ,! satellites
 ( ,jupit] are "h call$ 8! ,cosmian     
,/>s0     9 hon\r ( ,cosmo de' ,m$ici1 b
 else:]e ,galileo calls !m     8!       
,m$icean ,/>s40 ,kepl] sometimes calls  
!m 8! ,m$icean     ,/>s10 b m (t5       
8satellites40  ,sid5ote3 ,introduction4 
,,9 ! pres5t small treatise ,i set =? "s
 matt]s ( great int]e/ = all obs]v]s (  
natural ph5om5a to look at & consid]4   
,!y are ( great int]e/1 ,i ?9k1 fir/1 f 
_! intr9sic excell5ce2 secondly1 f _!   
absolute novelty2 & la/ly1 also on      
acc\nt ( ! in/rum5t by ! aid ( :i* !y h 
be5 pres5t$ to my appreh5sion4  ,! numb]
 ( ! ,fix$ ,/>s :i* obs]v]s h be5 able  
to see )\t artificial p[]s ( sight up to
 ?is day c be c\nt$4 ,x is !re=e        
decid$ly a great feat to add to _!      
numb]1 & to set di/9ctly be=e ! eyes o!r
 />s 9 myriads1 :i* h nev] be5 se5 be=e1
 & :i* surpass ! old1 previ\sly kn[n1   
/>s 9 numb] m ?an t5 times4  ,aga91 x is

 a mo/ beautiful & delightful sight to  
behold ! body ( ! ,moon1 :i* is di/ant f
 u ne>ly sixty semi-diamet]s#d ( ! ,e>?1
 z ne> z if x 0 at a di/ance ( only two 
( ! same measures2 s t ! diamet] ( ?is  
same ,moon appe>s ab\t ?irty times l>g]1
 its surface ab\t n9e hundr$ times1 &   
its solid mass ne>ly #bg1jjj times l>g] 
?an :5 x is view$ only ) ! nak$ eye2 &  
consequ5tly any "o may "k ) ! c]ta9ty t 
is due to ! use ( our s5ses1 t ! ,moon  
c]ta9ly does n possess a smoo? & poli%$ 
surface1 b "o r\gh & unev51 &1 j l !    
face ( ! ,e>? itself1 is ev]y:]e full ( 
va/ protub]ances1 deep *asms1 &         
s9uosities4      #d ,galileo says1 8p]  
sex d5as f]e t]re/res diametros a       
nobis remotum0 by mi/ake =              
semi-diametros1 & ! same     mi/ake     
occurs 9 p4 #aa4  ,!n to h got rid (    
disputes ab\t ! ,galaxy or ,milky ,way1 
& to h made its nature cle> to ! v      
s5ses1 n to say to ! und]/&+1 seems by  
no means a matt] :i* ought to be        
consid]$ ( slight importance4 ,9        

addition to ?is1 to po9t out1 z ) "o's  
f+]1 ! nature ( ^? />s :i* e "o ( !     
a/ronom]s up to ?is "t has call$        
nebul\s1 & to demon/rate t x is v       
diff]5t f :at has hi!rto be5 believ$1 w 
be pleasant1 & v f9e4 ,b t :i* w excite 
! greate/ a/oni%m5t by f>1 & :i* inde$  
especially mov$ me to call ! att5tion ( 
all a/ronom]s & philosoph]s1 is ?is1    
namely1 t ,i h discov]$ f\r planets1    
nei!r kn[n nor obs]v$ by any "o ( !     
a/ronom]s be=e my "t1 :i* h _! orbits   
r\nd a c]ta9 bright />1 "o ( ^?         
previ\sly kn[n1 l ,v5us & ,m]cury r\nd !
 ,sun1 & are sometimes 9 front ( x1     
sometimes beh9d x1 ?\gh !y nev] dep>t f 
x beyond c]ta9 limits4 ,all :i* facts 7 
discov]$ & obs]v$ a few days ago by !   
help ( a telescope#e devis$ by me1 ?r\gh
 ,god's grace fir/ enlight5+ my m9d4    
#e ,! words us$ by ,galileo =           
8telescope0 are p]spicillum1            
specillum in/rum5tum1 organum1 & oc*iale
 7,ital474     ,kepl] uses also ocul>e  
tubus1 arundo dioptrica4 ,! ^w          

8telescopium0 is us$ by ,gass5di1 #afdg4
  ,p]*ance o!r discov]ies /ill m        
excell5t w be made f "t to "t by me or  
by o!r obs]v]s1 ) ! assi/ance ( a simil>
 in/rum5t1 s ,i w fir/ briefly record   
its %ape & prep>ation1 z well z !       
occasion ( its be+ devis$1 & !n ,i w    
give an acc\nt ( ! obs]vations made by  
me4  ,sid5ote3 ,galileo's acc\nt ( !    
inv5tion ( 8 telescope4  ,ab\t t5 mon?s 
ago a report rea*$ my e>s t a ,dut*man  
_h con/ruct$ a telescope1 by ! aid ( :i*
 visible objects1 al?\gh at a great     
di/ance f ! eye ( ! obs]v]1 7 se5       
di/9ctly z if ne>2 & "s pro(s ( its mo/ 
wond]ful p]=mances 7 report$1 :i* "s    
gave cr$5ce to1 b o!rs contradict$4 ,a  
few days aft]1 ,i receiv$ confirmation (
 ! report 9 a lett] writt5 f ,p>is by a 
noble ,fr5*man1 ,jaques ,badov]e1 :i*   
f9ally det]m9$ me to give myself up fir/
 to inquire into ! pr9ciple ( !         
telescope1 & !n to consid] ! means by   
:i* ,i might compass ! inv5tion ( a     
simil> in/rum5t1 :i* a little :ile aft] 

,i succe$$ 9 do+1 ?r\gh deep /udy ( !   
!ory ( ,refraction2 & ,i prep>$ a tube1 
at fir/ ( lead1 9 ! ends ( :i* ,i fitt$ 
two glass l5ses1 bo? plane on "o side1 b
 on ! o!r side "o sph]ically convex1 & !
 o!r concave4 ,!n br++ my eye to !      
concave l5s ,i saw objects              
satisfactorily l>ge & ne>1 = !y appe>$  
"o-?ird ( ! di/ance (f & n9e times l>g] 
?an :5 !y are se5 ) ! natural eye alone4
 ,i %ortly aft]w>ds con/ruct$ ano!r     
telescope ) m nicety1 :i* magnifi$      
objects m ?an sixty times4 ,at l5g?1 by 
sp>+ nei!r lab\r nor exp5se1 ,i succe$$ 
9 con/ruct+ = myself an in/rum5t s      
sup]ior t objects se5 ?r\gh x appe>     
magnifi$ ne>ly a ?\s& times1 & m ?an    
?irty times ne>] ?an if view$ by !      
natural p[]s ( sight alone4  ,sid5ote3  
,galileo's fir/ obs]vations ) 8         
telescope4  ,x w\ld be altoge!r a wa/e (
 "t to enum]ate ! numb] & importance ( !
 b5efits :i* ?is in/rum5t may be expect$
 to conf]1 :5 us$ by l& or sea4 ,b )\t  
pay+ att5tion to its use = t]re/rial    

objects1 ,i betook myself to obs]vations
 ( ! heav5ly bodies2 & fir/ ( all1 ,i   
view$ ! ,moon z ne> z if x 0 sc>cely two
 semi-diamet]s#f ( ! ,e>? di/ant4 ,aft] 
! ,moon1 ,i frequ5tly obs]v$ o!r heav5ly
 bodies1 bo? fix$ />s & planets1 )      
incr$ible delight2 &1 :5 ,i saw _! v    
great numb]1 ,i began to consid] ab\t a 
me?od by :i* ,i might be able to measure
 _! di/ances ap>t1 & at l5g? ,i f\nd "o4
 ,& "h x is fitt+ t all :o int5d to turn
 _! att5tion to obs]vations ( ?is k9d   
%\ld receive c]ta9 cautions4 ,=1 9 !    
fir/ place1 x is absolutely necess>y =  
!m to prep>e a mo/ p]fect telescope1 "o 
:i* w %[ v bright objects di/9ct & free 
f any mi/9ess1 & w magnify !m at lea/   
#djj times1 = !n x w %[ !m z if only    
"o-tw5tie? ( _! di/ance (f4 ,= unless ! 
in/rum5t be ( su* p[]1 x w be 9 va9 to  
attempt to view all ! ?+s :i* h be5 se5 
by me 9 ! heav5s1 or :i* w be enum]at$  
h]eaft]4      #f 8,vix p] duas ,telluris
 diametros10 by mi/ake =                
8semi-diametros40  ,sid5ote3 ,me?od (   

det]m9+ ! magnify+ p[] ( ! telescope4   
,b 9 ord] t any "o may be a little m    
c]ta9 ab\t ! magnify+ p[] ( 8 in/rum5t1 
he %all fa%ion two circles1 or two squ>e
 pieces ( pap]1 "o ( :i* is #djj times  
great] ?an ! o!r1 b t w be :5 ! diamet] 
( ! great] is tw5ty times ! l5g? ( !    
diamet] ( ! o!r4 ,!n he %all view f a   
di/ance simultane\sly bo? surfaces1 fix$
 on ! same wall1 ! small] ) "o eye      
appli$ to ! telescope1 & ! l>g] ) ! o!r 
eye unassi/$2 = t may be done )\t       
inconv5i5ce at "o & ! same in/ant ) bo? 
eyes op54 ,!n bo? figures w appe> ( !   
same size1 if ! in/rum5t magnifies      
objects 9 ! desir$ proportion4          
,sid5ote3 ,me?od ( measur+ small angul> 
di/ances betwe5 heav5ly bodies by ! size
 ( ! ap]ture ( ! telescope4  ,aft] su*  
an in/rum5t has be5 prep>$1 ! me?od (   
measur+ di/ances rema9s = inquiry1 & ?is
 we %all accompli% by ! foll[+          
contrivance3--  ,illu/ration  ,= ! sake 
( be+ m easily und]/ood1 ,i w suppose a 
tube ,a ,b ,c ,d4#g ,let ,e be ! eye ( !

 obs]v]2 !n1 :5 !re are no l5ses 9 !    
tube rays f ! eye to ! object ,f ,g w\ld
 be drawn 9 ! /raight l9es ,e ,c ,f1 ,e 
,d ,g1 b :5 ! l5ses h be5 ins]t$1 let ! 
rays g 9 ! b5t l9es ,e ,c ,h1 ,e ,d     
,i1--= !y are contract$1 & ^? :i*       
orig9ally1 :5 unaffect$ by ! l5ses1 7   
direct$ to ! object ,f ,g1 w include    
only ! "p ,h ,i4 ,h5ce ! ratio ( !      
di/ance ,e ,h to ! l9e ,h ,i be+ kn[n1  
we %all be able to f9d1 by means ( a    
table ( s9es1 ! magnitude ( ! angle     
subt5d$ at ! eye by ! object ,h ,i1 :i* 
we %all f9d to conta9 only "s m9utes4 ,b
 if we fit on ! l5s ,c ,d ?9 plates (   
metal1 pi]c$1 "s ) l>g]1 o!rs ) small]  
ap]tures1 by putt+ on ov] ! l5s         
sometimes "o plate1 sometimes ano!r1 z  
may be necess>y1 we %all con/ruct at our
 pleasure diff]5t subt5d+ angles ( m or 
few] m9utes1 by ! help ( :i* we %all be 
able to measure conv5i5tly ! int]vals   
betwe5 />s sep>at$ by an angul> di/ance 
( "s m9utes1 )9 an error ( "o or two    
m9utes4 ,b let x suffice = ! pres5t to h

 ?us slightly t\*$1 & z x 7 j put our   
lips to ^! matt]s1 = on "s o!r          
opportunity ,i w publi% ! !ory ( ?is    
in/rum5t 9 complet5ess4      #g         
,illu/ration      ,! l9e ,c ,h 9        
,galileo's figure repres5ts ! small     
p5cil (     rays f ,h :i*1 aft]         
refraction ?r\gh ! telescope1 rea*     !
 eye ,e4 ,! enl>g$ figure %[s t if ,o ,p
 be ! radius (     ! ap]ture employ$1 ! 
po9t ,h ( ! object w\ld be j     outside
 ! field ( view4 ,! me?od1 h[ev]1 is at 
be/ only     a v r\gh "o1 z ! b\nd>y ( !
 field ( view 9 ?is     telescope is    
unavoidably indi/9ct4  ,n[ let me review
 ! obs]vations made by me dur+ ! two    
mon?s j pa/1 aga9 invit+ ! att5tion (   
all :o are eag] = true philosophy to !  
beg9n+s :i* l$ to ! sight ( mo/         
important ph5om5a4  ,sid5ote3 ,! ,moon4 
,rugg$ness ( its surface4 ,exi/5ce (    
lun> m\nta9s & valleys4  ,let me speak  
fir/ ( ! surface ( ! ,moon1 :i* is turn$
 t[>ds u4 ,= ! sake ( be+ und]/ood m    
easily1 ,i di/+ui% two p>ts 9 x1 :i* ,i 

call respectively ! bright] & ! d>k]4 ,!
 bright] "p seems to surr\nd & p]vade ! 
:ole hemisph]e2 b ! d>k] "p1 l a sort ( 
cl\d1 discol\rs ! ,moon's surface &     
makes x appe> cov]$ ) spots4 ,n[ ^!     
spots1 z !y are some:at d>k & (         
consid]able size1 are pla9 to e "o1 & e 
age has se5 !m1 :]e=e ,i %all call !m   
great or anci5t spots1 to di/+ui% !m f  
o!r spots1 small] 9 size1 b s ?ickly    
scatt]$ t !y spr9kle ! :ole surface ( ! 
,moon1 b especially ! bright] portion ( 
x4 ,^! spots h nev] be5 obs]v$ by any "o
 be=e me2 & f my obs]vations ( !m1 (t5  
repeat$1 ,i h be5 l$ to t op9ion :i* ,i 
h express$1 namely1 t ,i feel sure t !  
surface ( ! ,moon is n p]fectly smoo?1  
free f inequalities & exactly sph]ical1 
z a l>ge s*ool ( philosoph]s consid]s ) 
reg>d to ! ,moon & ! o!r heav5ly bodies1
 b t1 on ! contr>y1 x is full (         
inequalities1 unev51 full ( holl[s &    
protub]ances1 j l ! surface ( ! ,e>?    
itself1 :i* is v>i$ ev]y:]e by l(ty     
m\nta9s & deep valleys4  ,sket*es by    

,galileo to %ew3--  ,illu/ration3 !     
ind5tation ( ! t]m9ator & illum9at$     
summits ( m\nta9s 9 ! d>k "p ( ! moon2  
,illu/ration3 ! %ape ( a lun> m\nta9 & (
 a wall$ pla94 ,galileo3 #8,sid]eus     
,nuncius1' ,v5ice #afaj4  ,! appe>ances 
f :i* we may ga!r ^! conclusions are ( !
 foll[+ nature3--,on ! f\r? or fif? day 
aft] new-moon1 :5 ! ,moon pres5ts itself
 to u ) bright horns1 ! b\nd>y :i*      
divides ! "p 9 %ad[ f ! enlight5$ "p    
does n ext5d cont9u\sly 9 an ellipse1 z 
w\ld happ5 9 ! case ( a p]fectly        
sph]ical body1 b x is m>k$ out by an    
irregul>1 unev51 & v wavy l9e1 z        
repres5t$ 9 ! figure giv51 = sev]al     
bright excresc5ces1 z !y may be call$1  
ext5d beyond ! b\nd>y ( light & %ad[    
into ! d>k "p1 & on ! o!r h& pieces (   
%ad[ encroa* ^u ! light3--nay1 ev5 a    
great quantity ( small blacki% spots1   
altoge!r sep>at$ f ! d>k "p1 spr9kle    
ev]y:]e almo/ ! :ole space :i* is at !  
"t flood$ ) ! ,sun's light1 ) !         
exception ( t "p alone :i* is occupi$ by

 ! great & anci5t spots4 ,i h notic$ t !
 small spots j m5tion$ h ?is common     
*>act]i/ic always & 9 e case1 t !y h !  
d>k "p t[>ds ! ,sun's position1 & on !  
side away f ! ,sun !y h bright]         
b\nd>ies1 z if !y 7 cr[n$ ) %9+ summits4
 ,n[ we h an appe>ance q simil> on !    
,e>? ab\t sunrise1 :5 we behold !       
valleys1 n yet flood$ ) light1 b !      
m\nta9s surr\nd+ !m on ! side opposite  
to ! ,sun already ablaze ) ! spl5d\r ( 8
 beams2 & j z ! %ad[s 9 ! holl[s ( !    
,e>? dim9i% 9 size z ! ,sun rises high]1
 s also ^! spots on ! ,moon lose _!     
blackness z ! illum9at$ "p gr[s l>g] &  
l>g]4 ,aga91 n only are ! b\nd>ies (    
light & %ad[ 9 ! ,moon se5 to be unev5 &
 s9u\s1 b--& ?is produces /ill great]   
a/oni%m5t--!re appe> v _m bright po9ts  
)9 ! d>k5$ portion ( ! ,moon1 altoge!r  
divid$ & brok5 (f f ! illum9at$ tract1 &
 sep>at$ f x by no inconsid]able        
int]val1 :i*1 aft] a little :ile1       
gradually increase 9 size & brightness1 
& aft] an h\r or two become jo9$ on to !

 re/ ( ! bright portion1 n[ become      
some:at l>g]2 b 9 ! meantime o!rs1 "o "h
 & ano!r !re1 %oot+ up z if gr[+1 are   
light$ up )9 ! %ad$ portion1 increase 9 
size1 & at la/ are l9k$ on to ! same    
lum9\s surface1 n[ /ill m ext5d$4 ,an   
example ( ?is is giv5 9 ! same figure4  
,n[1 is x n ! case on ! ,e>? be=e       
sunrise1 t :ile ! level pla9 is /ill 9  
%ad[1 ! peaks ( ! mo/ l(ty m\nta9s are  
illum9at$ by ! ,sun's rays8 ,aft] a     
little :ile does n ! light spread fur!r1
 :ile ! middle & l>g] p>ts ( ^? m\nta9s 
are becom+ illum9at$2 & at l5g?1 :5 !   
,sun has ris51 d n ! illum9at$ p>ts ( ! 
pla9s & hills jo9 toge!r8 ,! gr&eur1    
h[ev]1 ( su* prom95ces & depressions 9 !
 ,moon seems to surpass bo? 9 magnitude 
& ext5t ! rugg$ness ( ! ,e>?'s surface1 
z ,i %all h]eaft] %[4 ,& "h ,i _c refra9
 f m5tion+ :at a rem>kable spectacle ,i 
obs]v$ :ile ! ,moon 0 rapidly approa*+  
h] fir/ qu>t]1 a repres5tation ( :i* is 
giv5 9 ! same illu/ration1 plac$        
opposite page #af4 ,a protub]ance ( !   

%ad[1 ( great size1 ind5t$ ! illum9at$  
"p 9 ! neighb\rhood ( ! l[] cusp2 & :5  
,i _h obs]v$ ?is ind5tation long]1 & _h 
se5 t x 0 d>k ?r\gh\t1 at l5g?1 aft]    
ab\t two h\rs1 a bright peak began to   
arise a little bel[ ! middle ( !        
depression2 ?is by degrees increas$1 &  
pres5t$ a triangul> %ape1 b 0 z yet q   
deta*$ & sep>at$ f ! illum9at$ surface4 
,soon ar\nd x ?ree o!r small po9ts began
 to %9e1 until1 :5 ! ,moon 0 j ab\t to  
set1 t triangul> figure1 hav+ n[ ext5d$ 
& wid5$1 began to be connect$ ) ! re/ ( 
! illum9at$ "p1 &1 /ill girt ) ! ?ree   
bright peaks already m5tion$1 sudd5ly   
bur/ into ! ind5tation ( %ad[ l a va/   
promontory ( light4  ,at ! ends ( ! upp]
 & l[] cusps also c]ta9 bright po9ts1 q 
away f ! re/ ( ! bright "p1 began to    
rise out ( ! %ad[1 z is se5 depict$ 9 ! 
same illu/ration4  ,sid5ote3 ,! lun>    
spots are sugge/$ to be possibly seas   
bord]$ by ranges ( m\nta9s4  ,9 bo?     
horns also1 b especially 9 ! l[] "o1 !re
 0 a great quantity ( d>k spots1 ( :i*  

^? :i* are ne>] ! b\nd>y ( light & %ad[ 
appe> l>g] & d>k]1 b ^? :i* are m remote
 less d>k & m indi/9ct4 ,9 all cases1   
h[ev]1 j z ,i h m5tion$ be=e1 ! d>k     
portion ( ! spot faces ! position ( !   
,sun's illum9ation1 & a bright] edge    
surr\nds ! d>k5$ spot on ! side away f !
 ,sun1 & t[>ds ! region ( ! ,moon 9     
%ad[4 ,?is "p ( ! surface ( ! ,moon1 :]e
 x is m>k$ ) spots l a peacock's tail ) 
its azure eyes1 is r5d]$ l ^? glass     
vases :i*1 ?r\gh be+ plung$ :ile /ill   
hot f ! kiln into cold wat]1 acquire a  
crackl$ & wavy surface1 f :i*           
circum/ance !y are commonly call$ fro/$ 
glasses4#h ,n[ ! great spots ( ! ,moon  
obs]v$ at ! same "t are n se5 to be at  
all simil>ly brok51 or full (           
depressions & prom95ces1 b r to be ev5 &
 uni=m2 = only "h & !re "s spaces1 r    
bright] ?an ! re/1 crop up2 s t if any  
"o wi%es to revive ! old op9ion ( !     
,py?agoreans1 t ! ,moon is ano!r ,e>?1 s
 to say1 ! bright] portion may v fitly  
repres5t ! surface ( ! l&1 & ! d>k] !   

expanse ( wat]4 ,inde$1 ,i h nev] d\bt$ 
t if ! sph]e ( ! ,e>? 7 se5 f a di/ance1
 :5 flood$ ) ! ,sun's rays1 t "p ( !    
surface :i* is l& w\ld pres5t itself to 
view z bright]1 & t :i* is wat] z d>k] 9
 comp>ison4 ,moreov]1 ! great spots 9 ! 
,moon are se5 to be m depress$ ?an !    
bright] tracts2 = 9 ! ,moon1 bo? :5     
cresc5t & :5 wan+1 on ! b\nd>y betwe5 ! 
light & %ad[1 :i* projects 9 "s places  
r\nd ! great spots1 ! adjac5t regions   
are always bright]1 z ,i h notic$ 9     
draw+ my illu/rations1 & ! edges ( !    
spots ref]r$ to are n only m depress$   
?an ! bright] p>ts1 b are m ev51 & are n
 brok5 by ridges or rugg$nesses4 ,b !   
bright] "p /&s out mo/ ne> ! spots1 s t 
bo? be=e ! fir/ qu>t] & ab\t ! ?ird     
qu>t] also1 ar\nd a c]ta9 spot 9 ! upp] 
"p ( ! figure1 t is1 occupy+ ! nor!rn   
region ( ! ,moon1 "s va/ prom95ces on ! 
upp] & l[] sides ( x rise to an enorm\s 
elevation1 z ! illu/rations %[4 ,?is    
same spot be=e ! ?ird qu>t] is se5 to be
 wall$ r\nd ) b\nd>ies ( a deep] %ade1  

:i* j l v l(ty m\nta9 summits appe> d>k]
 on ! side away f ! ,sun1 & bright] on !
 side :]e !y face ! ,sun2 b 9 ! case ( !
 cavities ! opposite happ5s1 = ! "p ( !m
 away f ! ,sun appe>s brilliant1 & t "p 
:i* lies ne>] to ! ,sun d>k & 9 %ad[4   
,aft] a "t1 :5 ! enlight5$ portion ( !  
,moon's surface has dim9i%$ 9 size1 z   
soon z ! :ole or ne>ly s ( ! spot       
already m5tion$ is cov]$ ) %ad[1 !      
bright] ridges ( ! m\nta9s m\nt high    
above ! %ade4 ,^! two appe>ances are %[n
 9 ! illu/rations :i* are giv54      #h 
,specim5s ( fro/$ or crackl$ ,v5etian   
glass are to be     se5 9 ! ,slade      
,collection1 ,briti% ,museum1 & fully   
ju/ify     ,galileo's comp>ison4        
,sid5ote3 ,description ( a lun> crat]1  
p]haps ,ty*o4#i      #i ,webb1 ,cele/ial
 ,objects = ,common ,telescopes1 p4     
#ajd1     sugge/s ?is id5tification4    
,!re is "o o!r po9t :i* ,i mu/ on no    
acc\nt =get1 :i* ,i h notic$ & r wond]$ 
at4 ,x is ?is3--,! middle ( ! ,moon1 z x
 seems1 is occupi$ by a c]ta9 cavity    

l>g] ?an all ! re/1 & 9 %ape p]fectly   
r\nd4 ,i h look$ at ?is depression ne>  
bo? ! fir/ & ?ird qu>t]s1 & ,i h        
repres5t$ x z well z ,i c 9 ! second    
illu/ration already giv54 ,x produces ! 
same appe>ance z to effects ( light &   
%ade z a tract l ,bohemia w\ld produce  
on ! ,e>?1 if x 7 %ut 9 on all sides by 
v l(ty m\nta9s arrang$ on ! circumf]5ce 
( a p]fect circle2 = ! tract 9 ! ,moon  
is wall$ 9 ) peaks ( su* enorm\s height 
t ! fur!/ side adjac5t to ! d>k portion 
( ! ,moon is se5 ba!d 9 sunlight be=e ! 
b\nd>y betwe5 light & %ade rea*es       
half-way across ! circul> space4 ,b     
accord+ to ! *>act]i/ic prop]ty ( ! re/ 
( ! spots1 ! %ad$ portion ( ?is too     
faces ! ,sun1 & ! bright "p is t[>ds !  
d>k side ( ! ,moon1 :i* = ! ?ird "t ,i  
advise to be c>efully notic$ z a mo/    
solid pro( ( ! rugg$nesses & unev5nesses
 spread ov] ! :ole ( ! bright region ( !
 ,moon4 ,( ^! spots1 moreov]1 ! d>ke/   
are always ^? :i* are ne> to !          
b\nd>y-l9e betwe5 ! light & ! %ad[1 b ^?

 fur!r (f appe> bo? small] 9 size & less
 decid$ly d>k2 s t at l5g?1 :5 ! ,moon  
at opposition becomes full1 ! d>kness ( 
! cavities diff]s f ! brightness ( !    
prom95ces ) a subdu$ & v slight         
diff]5ce4  ,sid5ote3 ,reasons = believ+ 
t !re is a diff]5ce ( con/itution 9     
v>i\s p>ts ( ! ,moon's surface4  ,^!    
ph5om5a :i* we h review$ are obs]v$ 9 ! 
bright tracts ( ! ,moon4 ,9 ! great     
spots we d n see su* diff]5ces (        
depressions & prom95ces z we are        
compell$ to recognise 9 ! bright] p>ts1 
ow+ to ! *ange ( _! %apes "u diff]5t    
degrees ( illum9ation by ! ,sun's rays  
accord+ to ! manifold v>iety ( ! ,sun's 
position ) reg>d to ! ,moon4 ,/ill1 9 ! 
great spots !re d exi/ "s spaces r less 
d>k ?an ! re/1 z ,i h not$ 9 !          
illu/rations1 b ^! spaces always h !    
same appe>ance1 & ! dep? ( _! %ad[ is   
nei!r int5sifi$ nor dim9i%$2 !y d appe> 
inde$ sometimes a little m %ad$1        
sometimes a little less1 b ! *ange (    
col\r is v slight1 accord+ z ! ,sun's   

rays fall ^u !m m or less obliquely2 &  
besides1 !y are jo9$ to ! adjac5t p>ts (
 ! spots ) a v gradual connection1 s t  
_! b\nd>ies m+le & melt into ! surr\nd+ 
region4 ,b x is q diff]5t ) ! spots :i* 
occupy ! bright] p>ts ( ! ,moon's       
surface1 =1 j z if !y 7 precipit\s crags
 ) num]\s rugg$ & jagg$ peaks1 !y h     
well-def9$ b\nd>ies ?r\gh ! %>p contra/ 
( light & %ade4 ,moreov]1 inside ^?     
great spots c]ta9 o!r tracts are se5    
bright] ?an ! surr\nd+ region1 & "s ( !m
 v bright inde$1 b ! appe>ance ( ^!1 z  
well z ( ! d>k] p>ts1 is always ! same2 
!re is no *ange ( %ape or brightness or 
dep? ( %ad[1 s t x becomes a matt] (    
c]ta9ty & beyond d\bt t _! appe>ance is 
ow+ to real dissimil>ity ( p>ts1 & n to 
unev5nesses only 9 _! configuration1    
*ang+ 9 diff]5t ways ! %ad[s ( ! same   
p>ts accord+ to ! v>iations ( _!        
illum9ation by ! ,sun1 :i* really happ5s
 9 ! case ( ! o!r small] spots occupy+ !
 bright] portion ( ! ,moon1 = day by day
 !y *ange1 increase1 decrease1 or       

disappe>1 inasmu* z !y d]ive _! orig9   
only f ! %ad[s ( prom95ces4  ,sid5ote3  
,explanation ( ! ev5ness ( ! illum9at$  
"p ( ! circumf]5ce ( ! ,moon's orb by ! 
analogy ( t]re/rial ph5om5a1 or by a    
possible lun> atmosph]e4  ,b "h ,i feel 
t "s p may be tr\bl$ ) grave d\bt1 &    
p]haps seiz$ ) a difficulty s s]i\s z to
 compel !m to feel unc]ta9 ab\t !       
conclusion j expla9$ & support$ by s _m 
ph5om5a4 ,= if t "p ( ! ,moon's surface 
:i* reflects ! ,sun's rays mo/ brightly 
is full ( s9uosities1 protub]ances1 &   
cavities innum]able1 :y1 :5 ! ,moon is  
increas+1 does ! out] edge :i* looks    
t[>d ! we/1 :5 ! ,moon is wan+1 ! o!r   
half-circumf]5ce t[>ds ! ea/1 & at      
full-moon ! :ole circle1 appe> n unev51 
rugg$1 & irregul>1 b p]fectly r\nd &    
circul>1 z %>ply def9$ z if m>k$ out ) a
 pair ( compasses1 & )\t ! ind5tations (
 any protub]ances or cavities8 ,& mo/   
rem>kably s1 because ! :ole unbrok5 edge
 belongs to t "p ( ! ,moon's surface :i*
 possesses ! prop]ty ( appe>+ bright]   

?an ! re/1 :i* ,i h said to be ?r\gh\t  
full ( protub]ances & cavities4 ,= n "o 
( ! ,great ,spots ext5ds q to !         
circumf]5ce1 b all ( !m are se5 to be   
toge!r away f ! edge4 ,( ?is ph5om5on1  
:i* af=ds a h&le = su* s]i\s d\bt1 ,i   
produce two causes1 & s two solutions ( 
! difficulty4  ,! fir/ solution :i* ,i  
(f] is ?is3--,if ! protub]ances &       
cavities 9 ! body ( ! ,moon exi/$ only  
on ! edge ( ! circle t b\nds ! hemisph]e
 :i* we see1 !n ! ,moon might1 or r mu/1
 %[ itself to u ) ! appe>ance ( a too!d 
:eel1 be+ b\nd$ ) an irregul> & unev5   
circumf]5ce2 b if1 in/ead ( a s+le set (
 prom95ces arrang$ along ! actual       
circumf]5ce only1 v _m ranges ( m\nta9s 
) _! cavities & rugg$nesses are set "o  
beh9d ! o!r along ! extreme edge ( !    
,moon1 & t too n only 9 ! hemisph]e :i* 
we see1 b also 9 t :i* is turn$ away f  
u1 b /ill ne> ! b\nd>y ( ! hemisph]e1 !n
 ! eye1 view+ !m af> (f1 w n at all be  
able to detect ! diff]5ces ( prom95ces &
 cavities1 = ! int]vals betwe5 ! m\nta9s

 situat$ 9 ! same circle1 or 9 ! same   
*a91 are hidd5 by ! jutt+ =w>d ( o!r    
prom95ces situat$ 9 o!r ranges1 &       
especially if ! eye ( ! obs]v] is plac$ 
9 ! same l9e ) ! tops ( ! prom95ces     
m5tion$4 ,s on ! ,e>?1 ! summits ( a    
numb] ( m\nta9s close toge!r appe>      
situat$ 9 "o plane1 if ! spectator is a 
long way (f & /&+ at ! same elevation4  
,s :5 ! sea is r\gh1 ! tops ( ! waves   
seem to =m "o plane1 al?\gh betwe5 !    
bill[s !re is _m a gulf & *asm1 s deep t
 n only ! hulls1 b ev5 ! bulw>ks1 ma/s1 
& sails ( /ately %ips are hidd5 among/  
!m4 ,!re=e1 z )9 ! ,moon1 z well z r\nd 
h] circumf]5ce1 !re is a manifold       
arrangem5t ( prom95ces & cavities1 & !  
eye1 reg>d+ !m f a great di/ance1 is    
plac$ 9 ne>ly ! same plane ) _! summits1
 no "o ne$ ?9k x /range t !y pres5t     
!mselves to ! visual ray :i* j grazes !m
 z an unbrok5 l9e q free f unev5nesses4 
,to ?is explanation may be add$ ano!r1  
namely1 t !re is r\nd ! body ( ! ,moon1 
j z r\nd ! ,e>?1 an envelope ( "s       

sub/ance d5s] ?an ! re/ ( ! e!r1 :i* is 
suffici5t to receive & reflect ! ,sun's 
rays1 al?\gh x does n possess s mu*     
opaqu5ess z to be able to prev5t our    
see+ ?r\gh x--especially :5 x is n      
illum9at$4 ,t envelope1 :5 illum9at$ by 
! ,sun's rays1 r5d]s ! body ( ! ,moon   
app>5tly l>g] ?an x really is1 & w\ld be
 able to /op our sight f p5etrat+ to !  
solid body ( ! ,moon1 if its ?ickness 7 
great]2 n[1 x is ( great] ?ickness ab\t 
! circumf]5ce ( ! ,moon1 great]1 ,i     
mean1 n 9 actual ?ickness1 b ) ref]5ce  
to our sight-rays1 :i* cut x obliquely2 
& s x may /op our vision1 especially :5 
x is 9 a /ate ( brightness1 & may       
conceal ! true circumf]5ce ( ! ,moon on 
! side t[>ds ! ,sun4  ,illu/ration  ,?is
 may be und]/ood m cle>ly f ! adjo9+    
figure1 9 :i* ! body ( ! ,moon1 ,a ,b   
,c1 is surr\nd$ by an envelop+          
atmosph]e1 ,d ,e ,g4 ,an eye at ,f      
p5etrates to ! middle p>ts ( ! ,moon1 z 
at ,a1 ?r\gh a ?ickness1 ,d ,a1 ( !     
atmosph]e2 b t[>ds ! extreme p>ts a mass

 ( atmosph]e ( great] dep?1 ,e ,b1 %uts 
out its b\nd>y f our sight4 ,an argum5t 
9 fav\r ( ?is is1 t ! illum9at$ portion 
( ! ,moon appe>s ( l>g] circumf]5ce ?an 
! re/ ( ! orb :i* is 9 %ad[4  ,p]haps   
also "s w ?9k t ?is same cause af=ds a v
 reasonable explanation :y ! great]     
spots on ! ,moon are n se5 to rea* to ! 
edge ( ! circumf]5ce on any side1 al?\gh
 x might be expect$ t "s w\ld be f\nd   
ab\t ! edge z well z else:]e2 & x seems 
cr$ible t !re are spots !re1 b t !y _c  
be se5 because !y are hidd5 by a mass ( 
atmosph]e too ?ick & too bright = !     
sight to p5etrate4  ,illu/ration        
,sid5ote3 ,calculation to %[ t ! height 
( "s lun> m\nta9s exce$s f\r ,italian   
miles#aj 7#bb1jjj ,briti% feet74        
#aj ,9 ! li/ ( ! heights ( lun> m\nta9s 
det]m9$ by     ,be] & ,ma$l]1 giv5 9 _! 
"w ,d] ,mond 7,b]l91 #ahcg71     !re are
 six :i* exce$ #cjjj toises1 or #ai1jjj 
,briti% feet4  ,i ?9k t x has be5       
suffici5tly made cle>1 f ! explanation (
 ph5om5a :i* h be5 giv51 t ! bright] "p 

( ! ,moon's surface is dott$ ev]y:]e )  
protub]ances & cavities2 x only rema9s =
 me to speak ab\t _! size1 & to %[ t !  
rugg$nesses ( ! ,e>?'s surface are f>   
small] ?an ^? ( ! ,moon's2 small]1 ,i   
mean1 absolutely1 s to say1 & n only    
small] 9 proportion to ! size ( ! orbs  
on :i* !y are4 ,& ?is is pla9ly %[n     
?us3--,z ,i (t5 obs]v$ 9 v>i\s positions
 ( ! ,moon ) ref]5ce to ! ,sun1 t "s    
summits )9 ! portion ( ! ,moon 9 %ad[   
appe>$ illum9$1 al?\gh at "s di/ance f !
 b\nd>y ( ! light 7! t]m9ator71 by      
comp>+ _! di/ance ) ! complete diamet] (
 ! ,moon1 ,i le>nt t x sometimes exce$$ 
! "o-tw5tie? 7#a_/bj?7 "p ( ! diamet]4  
,suppose ! di/ance to be exactly #a_/bj?
 "p ( ! diamet]1 & let ! diagram        
repres5t ! ,moon's orb1 ( :i* ,c ,a ,f  
is a great circle1 ,e its c5tre1 & ,c ,f
 a diamet]1 :i* consequ5tly be>s to !   
diamet] ( ! ,e>? ! ratio #b3g2 & s9ce ! 
diamet] ( ! ,e>?1 accord+ to ! mo/ exact
 obs]vations1 conta9s #gjjj ,italian    
miles1 ,c ,f w be #bjjj1 & ,c ,e #ajjj1 

& ! #a_/bj? "p ( ! :ole1 ,c ,f1 #ajj    
miles4 ,also let ,c ,f be a diamet] ( ! 
great circle :i* divides ! bright "p ( !
 ,moon f ! d>k "p 7=1 ow+ to ! v great  
di/ance ( ! ,sun f ! ,moon ?is circle   
does n diff] s5sibly f a great "o71 &   
let ! di/ance ( ,a f ! po9t ,c be       
#a_/bj? "p ( t diamet]2 let ! radius ,e 
,a be drawn1 & let x be produc$ to cut !
 tang5t l9e ,g ,c ,d1 :i* repres5ts !   
ray t illum9es ! summit1 9 ! po9t ,d4   
,!n ! arc ,c ,a or ! /raight l9e ,c ,d w
 be #ajj ( su* units1 z ,c ,e conta9s   
#ajjj4 ,! sum ( ! squ>es ( ,d ,c1 ,c ,e 
is !re=e #a1jaj1jjj1 & ! squ>e ( ,d ,e  
is equal to ?is2 !re=e ! :ole ,e ,d w be
 m ?an #ajjd2 & ,a ,d w be m ?an #d (   
su* units1 z ,c ,e conta9$ #ajjj4 ,!re=e
 ! height ( ,a ,d 9 ! ,moon1 :i*        
repres5ts a summit rea*+ up to ! ,sun's 
ray1 ,g ,c ,d1 & sep>at$ f ! extremity  
,c by ! di/ance ,c ,d1 is m ?an #d      
,italian miles2 b 9 ! ,e>? !re are no   
m\nta9s :i* rea* to ! p]p5dicul> height 
ev5 ( "o mile4 ,we are !re=e left to    

conclude t x is cle> t ! prom95ces ( !  
,moon are l(ti] ?an ^? ( ! ,e>?4        
,sid5ote3 ,! fa9t illum9ation ( !       
,moon's disc ab\t new-moon expla9$ to be
 due to e>?-light4  ,i wi% 9 ?is place  
to assign ! cause ( ano!r lun> ph5om5on 
well wor?y ( notice1 & al?\gh ?is       
ph5om5on 0 obs]v$ by me n lately1 b _m  
ye>s ago1 & has be5 po9t$ out to "s ( my
 intimate fri5ds & pupils1 expla9$1 &   
assign$ to its true cause1 yet z !      
obs]vation ( x is r5d]$ easi] & m vivid 
by ! help ( a telescope1 ,i h consid]$ t
 x w\ld n be unsuitably introduc$ 9 ?is 
place1 b ,i wi% to introduce x *iefly 9 
ord] t ! connection & resemblance betwe5
 ! ,moon & ! ,e>? may appe> m pla9ly4   
,:5 ! ,moon1 bo? be=e & aft]            
conjunction1 is f\nd n f> f ! ,sun1 n   
only does its orb %[ itself to our sight
 on ! side :]e x is furni%$ ) %9+ horns1
 b a slight & fa9t circumf]5ce is also  
se5 to m>k out ! circle ( ! d>k "p1 t   
"p1 namely1 :i* is turn$ away f ! ,sun1 
& to sep>ate x f ! d>k] backgr\nd ( !   

sky4 ,b if we exam9e ! matt] m closely1 
we %all see t n only is ! extreme edge (
 ! "p 9 %ad[ %9+ ) a fa9t brightness1 b 
t ! entire face ( ! ,moon1 t side1 t is1
 :i* does n feel ! ,sun's gl>e1 is      
illum9at$ ) a pale light ( consid]able  
brightness4 ,at ! fir/ glance only a f9e
 circumf]5ce appe>s %9+1 on acc\nt ( !  
d>k] "p ( ! sky adjac5t to x2 :]eas1 on 
! contr>y1 ! re/ ( ! surface appe>s d>k1
 on acc\nt ( ! contiguity ( ! %9+ horns1
 :i* de/roys ! cle>ness ( our sight4 ,b 
if any "o *ooses su* a position =       
himself1 t by ! int]position ( a ro(1 or
 a *imney1 or "s o!r object betwe5 8    
sight & ! ,moon1 b at a consid]able     
di/ance f 8 eye1 ! %9+ horns are hidd51 
& ! re/ ( ! ,moon's orb is left expos$  
to 8 view1 !n he w f9d t ?is tract ( !  
,moon also1 al?\gh depriv$ ( sunlight1  
gleams ) consid]able light1 & p>ticul>ly
 s if ! gloom ( ! night has already     
deep5$ ?r\gh ! abs5ce ( ! ,sun2 = ) a   
d>k] backgr\nd ! same light appe>s      
bright]4 ,moreov]1 x is f\nd t ?is      

second>y brightness ( ! ,moon1 z ,i may 
call x1 is great] 9 proportion z ! ,moon
 is less di/ant f ! ,sun2 = x abates m &
 m 9 proportion to ! ,moon's di/ance f t
 body1 s mu* s t aft] ! fir/ qu>t]1 &   
be=e ! end ( ! second1 x is f\nd to be  
weak & v fa9t1 al?\gh x be obs]v$ 9 a   
d>k] sky2 :]eas1 at an angul> di/ance ( 
#fj or less1 ev5 dur+ twilight1 x is    
wond]fully bright1 s bright inde$ t1 ) !
 help ( a good telescope1 ! great spots 
may be di/+ui%$ 9 x4  ,?is /range       
brightness has af=d$ no small p]plexity 
to philosophical m9ds2 & "s h publi%$ "o
 ?+1 "s ano!r1 z ! cause to be alleg$ = 
x4 ,"s h said t x is ! inh]5t & natural 
brightness ( ! ,moon2 "s t x is imp>t$  
to t body by ! planet ,v5us2 or1 z o!rs 
ma9ta91 by all ! />s2 :ile "s h said t x
 comes f ! ,sun1 ^: rays1 !y say1 f9d a 
way ?r\gh ! solid mass ( ! ,moon4 ,b    
/atem5ts ( ?is k9d are disprov$ )\t mu* 
difficulty1 & conv9c+ly demon/rat$ to be
 false4 ,= if ?is k9d ( light 7 !       
,moon's own1 or 7 contribut$ by ! />s1 !

 ,moon w\ld reta9 x1 p>ticul>ly 9       
eclipses1 & w\ld %[ x !n1 :5 left 9 an  
unusually d>k sky1 b ?is is contr>y to  
exp]i5ce4 ,= ! brightness :i* is se5 on 
! ,moon 9 eclipses is f> less int5se1   
be+ some:at r$di%1 & almo/ copp]-col\r$1
 :]eas ?is is bright] & :it]2 besides1 !
 brightness se5 dur+ an eclipse is      
*angeable & %ift+1 = x w&]s ov] ! face (
 ! ,moon1 s t t "p :i* is ne> !         
circumf]5ce ( ! circle ( %ad[ ?r[n by ! 
,e>? is bright1 b ! re/ ( ! ,moon is    
always se5 to be d>k4 ,f :i* circum/ance
 we und]/& )\t hesitation t ?is         
brightness is due to ! proximity ( !    
,sun's rays com+ into contact ) "s d5s] 
region :i* surr\nds ! ,moon z an        
envelope2 ow+ to :i* contact a sort (   
dawn-light is diffus$ ov] ! neighb\r+   
regions ( ! ,moon1 j z ! twilight       
spreads 9 ! morn+ & ev5+ on ! ,e>?3#aa b
 ,i w treat m fully ( ?is matt] 9 my    
book ^u ! ,sy/em ( ! ,univ]se4#ab       
#aa ,! illum9ation ( ! ,moon 9 eclipses1
 notic$ by ,galileo1     is n[ ref]r$ to

 ! refraction ( ! sunlight by ! e>?'s   
atmosph]e1 & ! r$di% col\r ( ! light is 
expla9$ by     ,h]s*el 7,outl9es (      
,a/ronomy1 *4 vii47 to be due to !      
absorption ( ! violet & blue rays by !  
aque\s vap\r ( !     ,e>?'s atmosph]e4  
,! idea ( a s5sible lun> atmosph]e is n 
9 accordance ) ! obs]v$ ph5om5a ( !     
occultations (     />s4      #ab        
,galileo's ,sy/ema ,mundi4 ,ow+ to !    
viol5t opposition     provok$ by !      
discussion ( ! discov]ies ( ,galileo1 & 
_! be>+ on ! ,cop]nican sy/em (         
a/ronomy1 ,galileo seems     to h f\nd x
 necess>y to delay ! publication ( ?is  
"w     until #afcb1 :51 believ+ himself 
safe "u ! fri5d%ip &     patronage (    
,pope ,urban ,,viii4 & o!rs 9 p[] at    
,rome1 he     at l5g? publi%$ x4 ,urban1
 h[ev]1 n[ turn$ aga9/ him1     d5\nc$ !
 book & its au?or1 & summon$ him to     
,rome1 :]e     ! well-kn[n incid5ts ( 8 
trial & condemnation took place4  ,aga91
 to ass]t t ?is sort ( light is imp>t$  
to ! ,moon by ! planet ,v5us is s *ildi%

 z to be undes]v+ ( an answ]2 = :o is s 
ignorant z n to und]/& t at conjunction 
& )9 an angul> di/ance ( #fj x is q     
impossible = ! "p ( ! ,moon turn$ away f
 ! ,sun to be se5 by ! planet ,v5us8  ,b
 t ?is light is d]iv$ f ! ,sun p5etrat+ 
) its light ! solid mass ( ! ,moon1 &   
r5d]+ x lum9\s1 is equally unt5able4 ,= 
!n ?is light w\ld nev] less51 s9ce !    
hemisph]e ( ! ,moon is always illum9$ by
 ! ,sun1 except at ! mom5t ( a lun>     
eclipse1 yet really x quickly decreases 
:ile ! ,moon is draw+ ne> to ! end ( h] 
fir/ qu>t]1 & :5 %e has pass$ h] fir/   
qu>t] x becomes q dull4 ,s9ce1 !re=e1   
?is k9d ( second>y brightness is n      
inh]5t & ! ,moon's own1 nor borr[$ f any
 ( ! />s1 nor f ! ,sun1 & s9ce !re n[   
rema9s 9 ! :ole univ]se no o!r body     
:atev] except ! ,e>?1 :at1 pray1 mu/ we 
conclude8 ,:at mu/ we ass]t8 ,%all we   
ass]t t ! body ( ! ,moon1 or "s o!r d>k 
& sunless orb1 receives light f ! ,e>?8 
,:y %\ld x n be ! ,moon8 ,& mo/ c]ta9ly 
x is4 ,! ,e>?1 ) fair & grateful        

ex*ange1 pays back to ! ,moon an        
illum9ation l t :i* x receives f ! ,moon
 ne>ly ! :ole "t dur+ ! d>ke/ gloom (   
night4 ,let me expla9 ! matt] m cle>ly4 
,at conjunction1 :5 ! ,moon occupies a  
position betwe5 ! ,sun & ! ,e>?1 ! ,moon
 is illum9at$ by ! ,sun's rays on h]    
half t[>ds ! ,sun :i* is turn$ away f ! 
,e>?1 & ! o!r half1 ) :i* %e reg>ds !   
,e>?1 is cov]$ ) d>kness1 & s 9 no      
degree illum9es ! ,e>?'s surface4 ,:5 ! 
,moon has slightly sep>at$ f ! ,sun1    
/raightway %e is p>tly illum9$ on ! half
 direct$ t[>ds u2 %e turns t[>ds u a    
sl5d] silv]y cresc5t1 & slightly        
illum9es ! ,e>?2 ! ,sun's illum9ation   
increases ^u ! ,moon z %e approa*es h]  
fir/ qu>t]1 & ! reflexion ( t light     
increases on ! ,e>?2 ! brightness 9 !   
,moon next ext5ds beyond ! semicircle1 &
 our nights gr[ bright]2 at l5g? !      
entire face ( ! ,moon look+ t[>ds ! ,e>?
 is irradiat$ ) ! mo/ int5se brightness 
by ! ,sun1 :i* happ5s :5 ! ,sun & ,moon 
are on opposite sides ( ! ,e>?2 !n f> & 

wide ! surface ( ! ,e>? %9es ) ! flood (
 moonlight2 aft] ?is ! ,moon1 n[ wan+1  
s5ds out less p[]ful beams1 & ! ,e>? is 
illum9$ less p[]fully2 at l5g? ! ,moon  
draws ne> h] fir/ position ( conjunction
 ) ! ,sun1 & =?) black night invades !  
,e>?4 ,9 su* a cycle ! moonlight gives u
 ea* mon? alt]nations ( bright] & fa9t] 
illum9ation4 ,b ! b5efit ( h] light to !
 ,e>? is balanc$ & repaid by ! b5efit ( 
! light ( ! ,e>? to h]2 = :ile ! ,moon  
is f\nd ne> ! ,sun ab\t ! "t (          
conjunction1 %e has 9 front ( h] !      
entire surface ( t hemisph]e ( ! ,e>?   
:i* is expos$ to ! ,sun1 & vividly      
illum9$ ) 8 beams1 & s receives light   
reflect$ f ! ,e>?4 ,ow+ to su*          
reflexion1 ! hemisph]e ( ! ,moon ne>] to
 u1 ?\gh depriv$ ( sunlight1 appe>s (   
consid]able brightness4 ,aga91 :5 remov$
 f ! ,sun ?r\gh a quadrant1 ! ,moon sees
 only "o-half ( ! ,e>?'s hemisph]e      
illum9at$1 namely ! we/]n half1 = ! o!r1
 ! ea/]n1 is cov]$ ) ! %ades ( night2 ! 
,moon is1 !re=e1 less brightly enlight5$

 by ! ,e>?1 & accord+ly t second>y light
 appe>s fa9t] to u4 ,b if y imag9e !    
,moon to be set on ! opposite side ( !  
,e>? to ! ,sun1 %e w see ! hemisph]e ( !
 ,e>?1 n[ betwe5 ! ,moon & ! ,sun1 q    
d>k1 & /eep$ 9 ! gloom ( night2 if1     
!re=e1 an eclipse %\ld accompany su* a  
position ( ! ,moon1 %e w receive no     
light at all1 be+ depriv$ ( !           
illum9ation ( ! ,sun & ,e>? toge!r4 ,9  
any o!r position1 ) reg>d to ! ,e>? & ! 
,sun1 ! ,moon receives m or less light  
by reflexion f ! ,e>?1 accord+ z %e sees
 a great] or small] portion ( !         
hemisph]e ( ! ,e>? illum9at$ by ! ,sun2 
= su* a law is obs]v$ betwe5 ^! two     
orbs1 t at :atev] times ! ,e>? is mo/   
brightly enlight5$ by ! ,moon1 at ^?    
times1 on ! contr>y1 ! ,moon is lea/    
enlight5$ by ! ,e>?2 & contr>iwise4 ,let
 ^! few words on ?is subject suffice 9  
?is place2 = ,i w consid] x m fully 9 my
 ,sy/em ( ! ,univ]se1 :]e1 by v _m      
argum5ts & exp]im5tal pro(s1 !re is %[n 
to be a v /rong reflexion ( ! ,sun's    

light f ! ,e>?1 = ! b5efit ( ^? :o urge 
t ! ,e>? mu/ be sep>at$ f ! />ry ho/1   
*iefly = ! reason t x has nei!r motion  
nor light1 = ,i w prove t ! ,e>? has    
motion1 & surpasses ! ,moon 9           
brightness1 & is n ! place :]e ! dull   
refuse ( ! univ]se has settl$ d[n2 & ,i 
w support my demon/ration by a ?\s&     
argum5ts tak5 f natural ph5om5a4        
,sid5ote3 ,/>s4 ,_! appe>ance 9 !       
telescope4  ,hi!rto ,i h spok5 ( !      
obs]vations :i* ,i h made conc]n+ !     
,moon's body2 n[ ,i w briefly ann\nce ! 
ph5om5a :i* h be51 z yet1 se5 by me )   
ref]5ce to ! ,fix$ ,/>s4 ,& fir/ ( all !
 foll[+ fact is wor?y (                 
consid]ation3--,! />s1 fix$ z well z    
erratic1 :5 se5 ) a telescope1 by no    
means appe> to be increas$ 9 magnitude 9
 ! same proportion z o!r objects1 & !   
,moon h]self1 ga9 increase ( size2 b 9 !
 case ( ! />s su* increase appe>s mu*   
less1 s t y may consid] t a telescope1  
:i* 7= ! sake ( illu/ration7 is p[]ful  
en\gh to magnify o!r objects a hundr$   

times1 w sc>cely r5d] ! />s magnifi$ f\r
 or five times4 ,b ! reason ( ?is is z  
foll[s3--,:5 />s are view$ ) our natural
 eyesight !y d n pres5t !mselves to u ( 
_! b>e1 real size1 b beam+ ) a c]ta9    
vividness1 & fr+$ ) sp>kl+ rays1        
especially :5 ! night is f> advanc$2 & f
 ?is circum/ance !y appe> mu* l>g] ?an  
!y w\ld if !y 7 /ripp$ ( ^? adv5titi\s  
fr+es1 = ! angle :i* !y subt5d at ! eye 
is det]m9$ n by ! prim>y disc ( ! />1 b 
by ! brightness :i* s widely surr\nds x4
 ,p]haps y w und]/& ?is mo/ cle>ly f !  
well-kn[n circum/ance t :5 />s rise j at
 sunset1 9 ! beg9n+ ( twilight1 !y appe>
 v small1 al?\gh !y may be />s ( ! fir/ 
magnitude2 & ev5 ! planet ,v5us itself1 
on any occasion :5 x may pres5t itself  
to view 9 broad daylight1 is s small to 
see t x sc>cely seems to equal a /> ( ! 
la/ magnitude4 ,x is diff]5t 9 ! case ( 
o!r objects1 & ev5 ( ! ,moon1 :i*1 :e!r 
view$ 9 ! light ( midday or 9 ! dep? (  
night1 always appe>s ( ! same size4 ,we 
conclude !re=e t ! />s are se5 at       

midnight 9 uncurtail$ glory1 b _! fr+es 
are ( su* a nature t ! daylight c cut !m
 (f1 & n only daylight1 b any slight    
cl\d :i* may be int]pos$ betwe5 a /> & !
 eye ( ! obs]v]4 ,a d>k veil or col\r$  
glass has ! same effect1 =1 ^u plac+ !m 
be=e ! eye betwe5 x & ! />s1 all ! blaze
 t surr\nds !m leaves !m at once4 ,a    
telescope also accompli%es ! same       
result1 = x removes f ! />s _!          
adv5titi\s & accid5tal spl5d\rs be=e x  
enl>ges _! true discs 7if inde$ !y are (
 t %ape71 & s !y seem less magnifi$ ?an 
o!r objects1 = a /> ( ! fif? or six?    
magnitude se5 ?r\gh a telescope is %[n z
 ( ! fir/ magnitude only4  ,! diff]5ce  
betwe5 ! appe>ance ( ! planets & ! fix$ 
/>s seems also des]v+ ( notice4 ,!      
planets pres5t _! discs p]fectly r\nd1 j
 z if describ$ ) a pair ( compasses1 &  
appe> z s _m little moons1 completely   
illum9at$ & ( a globul> %ape2 b ! fix$  
/>s d n look to ! nak$ eye b\nd$ by a   
circul> circumf]5ce1 b r l blazes (     
light1 %oot+ out beams on all sides & v 

sp>kl+1 & ) a telescope !y appe> ( !    
same %ape z :5 !y are view$ by simply   
look+ at !m1 b s mu* l>g] t a /> ( !    
fif? or six? magnitude seems to equal   
,sirius1 ! l>ge/ ( all ! fix$ />s4#ac   
#ac ,! imm5se di/ance ( />s makes x     
impossible = !m to     be magnifi$ by   
any telescope1 h[ev] p[]ful2 ! app>5t or
     spuri\s disc is an optical effect1 
:i* dep5ds on ! telescope     us$1 & is 
smalle/ ) ! l>ge/ ap]ture4              
,illu/ration3 ,orion's ,belt & ,sword2  
#hc ,/>s  ,illu/ration3 ,pleiades2 #cf  
,/>s  ,galileo3 8,sid]eus ,nuncius40    
,sid5ote3 ,telescopic ,/>s3 _! inf9ite  
multitude4 ,z examples1 ,orion's ,belt &
 ,sword & ! ,pleiades are describ$ z se5
 by ,galileo4  ,b beyond ! />s ( ! six? 
magnitude y w behold ?r\gh ! telescope a
 ho/ ( o!r />s1 :i* escape ! unassi/$   
sight1 s num]\s z to be almo/ beyond    
belief1 = y may see m ?an six o!r       
diff]5ces ( magnitude1 & ! l>ge/ ( ^!1  
:i* ,i may call />s ( ! sev5? magnitude1
 or ( ! fir/ magnitude ( invisible />s1 

appe> ) ! aid ( ! telescope l>g] &      
bright] ?an />s ( ! second magnitude se5
 ) ! unassi/$ sight4 ,b 9 ord] t y may  
see "o or two pro(s ( ! inconceivable   
mann] 9 :i* !y are cr[d$ toge!r1 ,i h   
det]m9$ to make out a case aga9/ two    
/>-clu/]s1 t f !m z a specim5 y may     
decide ab\t ! re/4  ,z my fir/ example  
,i _h det]m9$ to depict ! entire        
con/ellation ( ,orion1 b ,i 0 ov]:elm$  
by ! va/ quantity ( />s & by want ( "t1 
& s ,i h def]r$ attempt+ ?is to ano!r   
occasion1 = !re are adjac5t to1 or      
scatt]$ among1 ! old />s m ?an five     
hundr$ new />s )9 ! limits ( "o or two  
degrees4 ,= ?is reason ,i h select$ !   
?ree />s 9 ,orion's ,belt & ! six 9 8   
,sword1 :i* h be5 long well-kn[n gr\ps1 
& ,i h add$ eighty o!r />s rec5tly      
discov]$ 9 _! vic9ity1 & ,i h pres]v$ z 
exactly z possible ! int]vals betwe5 !m4
 ,! well-kn[n or old />s1 = ! sake (    
di/9ction1 ,i h depict$ ( l>g] size1 &  
,i h outl9$ !m ) a d\ble l9e2 ! o!rs1   
invisible to ! nak$ eye1 ,i h m>k$      

small] & ) "o l9e only4 ,i h also       
pres]v$ ! diff]5ces ( magnitude z mu* z 
,i c\ld4  ,z a second example ,i h      
depict$ ! six />s ( ! con/ellation      
,taurus1 call$ ! ,pleiades 7,i say six  
int5tionally1 s9ce ! sev5? is sc>cely   
ev] visible71 a gr\p ( />s :i* is       
enclos$ 9 ! heav5s )9 v n>r[ prec9cts4  
,ne> ^! !re lie m ?an =ty o!rs invisible
 to ! nak$ eye1 no "o ( :i* is mu* m ?an
 half a degree (f any ( ! a=esaid six2 (
 ^! ,i h notic$ only ?irty-six 9 my     
diagram4 ,i h pres]v$ _! int]vals1      
magnitudes1 & ! di/9ction betwe5 ! old &
 ! new />s1 j z 9 ! case ( !            
con/ellation ,orion4  ,sid5ote3 ,!      
,milky ,way consi/s entirely ( />s 9    
c\ntless numb]s & ( v>i\s magnitudes4   
,! next object :i* ,i h obs]v$ is !     
ess5ce or sub/ance ( ! ,milky ,way4 ,by 
! aid ( a telescope any "o may behold   
?is 9 a mann] :i* s di/9ctly appeals to 
! s5ses t all ! disputes :i* h torm5t$  
philosoph]s ?r\gh s _m ages are explod$ 
at once by ! irrefragable evid5ce ( our 

eyes1 & we are fre$ f wordy disputes ^u 
?is subject1 = ! ,galaxy is no?+ else b 
a mass ( innum]able />s plant$ toge!r 9 
clu/]s4 ,^u :atev] "p ( x y direct !    
telescope /raightway a va/ cr[d ( />s   
pres5ts itself to view2 _m ( !m are     
tol]ably l>ge & extremely bright1 b !   
numb] ( small ones is q beyond          
det]m9ation4  ,illu/ration3 ,/>-clu/] 9 
,orion's ,head  ,illu/ration3 ,/>-clu/] 
( ,praesepe 9 ,canc]  ,galileo3         
8,sid]eus ,nuncius10 ,v5ice1 #afaj4     
,sid5ote3 ,nebul resolv$ into clu/]s (  
/>s3 z examples1 ! nebul 9 ,orion's     
,head & ,prsepe4  ,& :]eas t milky      
brightness1 l ! brightness ( a :ite     
cl\d1 is n only to be se5 9 ! ,milky    
,way1 b sev]al spots ( a simil> col\r   
%9e fa9tly "h & !re 9 ! heav5s1 if y    
turn ! telescope ^u any ( !m y w f9d a  
clu/] ( />s pack$ close toge!r4         
,fur!r--& y w be m surpris$ at ?is1--!  
/>s :i* h be5 call$ by e "o ( !         
a/ronom]s up to ?is day nebul\s1 are    
gr\ps ( small />s set ?ick toge!r 9 a   

wond]ful way1 & al?\gh ea* "o ( !m on   
acc\nt ( its smallness1 or its imm5se   
di/ance f u1 escapes our sight1 f !     
comm+l+ ( _! rays !re arises t          
brightness :i* has hi!rto be5 believ$ to
 be ! d5s] "p ( ! heav5s1 able to       
reflect ! rays ( ! />s or ! ,sun4  ,i h 
obs]v$ "s ( ^!1 & ,i wi% to subjo9 !    
/>-clu/]s ( two ( ^! nebul4 ,fir/1 y h a
 diagram ( ! nebula call$ t ( ,orion's  
,head1 9 :i* ,i h c\nt$ tw5ty-"o />s4   
,! second clu/] conta9s ! nebula call$  
,prsepe1 :i* is n "o /> only1 b a mass (
 m ?an =ty small />s4 ,i h notic$       
?irty-six />s1 besides ! ,aselli1       
arrang$ 9 ! ord] ( ! accompany+ diagram4
  ,sid5ote3 ,discov]y ( ,jupit]'s       
satellites1 ,jan4 #g1 #afaj3 record (   
,galileo's obs]vations dur+ two mon?s4  
,i h n[ f9i%$ my brief acc\nt ( !       
obs]vations :i* ,i h ?us f> made ) reg>d
 to ! ,moon1 ! ,fix$ ,/>s1 & ! ,galaxy4 
,!re rema9s ! matt]1 :i* seems to me to 
des]ve to be consid]$ ! mo/ important 9 
?is "w1 namely1 t ,i %\ld disclose &    

publi% to ! _w ! occasion ( discov]+ &  
obs]v+ f\r ,,planets1 nev] se5 f ! v    
beg9n+ ( ! _w up to our own times1 _!   
positions1 & ! obs]vations made dur+ !  
la/ two mon?s ab\t _! movem5ts & _!     
*anges ( magnitude2 & ,i summon all     
a/ronom]s to apply !mselves to exam9e & 
det]m9e _! p]iodic times1 :i* x has n   
be5 p]mitt$ me to a*ieve up to ?is day1 
ow+ to ! re/riction ( my "t4 ,i give !m 
w>n+ h[ev] aga91 s t !y may n approa*   
su* an inquiry to no purpose1 t !y w    
want a v accurate telescope1 & su* z ,i 
h describ$ 9 ! beg9n+ ( ?is acc\nt4  ,on
 ! #g? day ( ,janu>y 9 ! pres5t ye>1    
#afaj1 9 ! fir/#ad h\r ( ! foll[+ night1
 :5 ,i 0 view+ ! con/ellations ( !      
heav5s ?r\gh a telescope1 ! planet      
,jupit] pres5t$ itself to my view1 & z  
,i _h prep>$ = myself a v excell5t      
in/rum5t1 ,i notic$ a circum/ance :i* ,i
 _h nev] be5 able to notice be=e1 ow+ to
 want ( p[] 9 my o!r telescope1 namely1 
t ?ree little />s1 small b v bright1 7  
ne> ! planet2 & al?\gh ,i believ$ !m to 

belong to ! numb] ( ! fix$ />s1 yet !y  
made me some:at wond]1 because !y seem$ 
to be arrang$ exactly 9 a /raight l9e1  
p>allel to ! ecliptic1#ae & to be       
bright] ?an ! re/ ( ! />s1 equal to !m 9
 magnitude4 ,! position ( !m ) ref]5ce  
to "o ano!r & to ,jupit] 0 z foll[s     
7,fig4 #a74      #ad ,! times (         
,galileo's obs]vations are to be        
und]/ood z     reckon$ f sunset4        
#ae ,! satellites ( ,jupit] revolve 9   
planes v ne>ly1     al?\gh n exactly1   
co9cid5t ) t ( ! equator ( !     planet1
 :i* is incl9$ #c #e #cj to ! orbit ( ! 
planet1     & ! plane ( ! orbit is      
incl9$ #a #ah #ea to ! ecliptic4  ,on ! 
ea/ side !re 7 two />s1 & a s+le "o     
t[>ds ! we/4 ,! /> :i* 0 fur!/ t[>ds !  
ea/1 & ! we/]n />1 appe>$ r l>g] ?an !  
?ird4  ,i sc>cely tr\bl$ at all ab\t !  
di/ance betwe5 !m & ,jupit]1 =1 z ,i h  
already said1 at fir/ ,i believ$ !m to  
be fix$ />s2 b :5 on ,janu>y #h?1 l$ by 
"s fatality1 ,i turn$ aga9 to look at ! 
same "p ( ! heav5s1 ,i f\nd a v diff]5t 

/ate ( ?+s1 = !re 7 ?ree little />s all 
we/ ( ,jupit]1 & ne>] toge!r ?an on !   
previ\s night1 & !y 7 sep>at$ f "o ano!r
 by equal int]vals1 z ! accompany+      
illu/ration 7,fig4 #b7 %[s4  ,at ?is    
po9t1 al?\gh ,i _h n turn$ my ?\ghts at 
all ^u ! approximation ( ! />s to "o    
ano!r1 yet my surprise began to be      
excit$1 h[ ,jupit] c\ld "o day be f\nd  
to ! ea/ ( all ! a=esaid fix$ />s :5 !  
day be=e x _h be5 we/ ( two ( !m2 & =?) 
,i became afraid le/ ! planet might h   
mov$ diff]5tly f ! calculation (        
a/ronom]s1 & s _h pass$ ^? />s by its   
own prop] motion4 ,i !re=e wait$ = !    
next night ) ! mo/ int5se long+1 b ,i 0 
disappo9t$ ( my hope1 = ! sky 0 cov]$ ) 
cl\ds 9 e direction4  ,b on ,janu>y #aj?
 ! />s appe>$ 9 ! foll[+ position )     
reg>d to ,jupit]2 !re 7 two only1 & bo? 
on ! ea/ side ( ,jupit]1 ! ?ird1 z ,i   
?\ght1 be+ hidd5 by ! planet 7,fig4 #c74
 ,!y 7 situat$ j z be=e1 exactly 9 !    
same /raight l9e ) ,jupit]1 & along !   
,zodiac4  ,:5 ,i _h se5 ^! ph5om5a1 z ,i

 knew t correspond+ *anges ( position   
c\ld n by any means belong to ,jupit]1 &
 z1 moreov]1 ,i p]ceiv$ t ! />s :i* ,i  
saw _h be5 always ! same1 = !re 7 no    
o!rs ei!r 9 front or beh9d1 )9 a great  
di/ance1 along ! ,zodiac1--at l5g?1     
*ang+ f d\bt into surprise1 ,i discov]$ 
t ! int]*ange ( position :i* ,i saw     
belong$ n to ,jupit]1 b to ! />s to :i* 
my att5tion _h be5 drawn1 & ,i ?\ght    
!re=e t !y ought to be obs]v$ h5ce=w>d )
 m att5tion & precision4  ,accord+ly1 on
 ,janu>y #aa? ,i saw an arrangem5t ( !  
foll[+ k9d 7,fig4 #d71 namely1 only two 
/>s to ! ea/ ( ,jupit]1 ! ne>] ( :i* 0  
di/ant f ,jupit] ?ree times z f> z f !  
/> fur!r to ! ea/2 & ! /> fur!/ to ! ea/
 0 ne>ly twice z l>ge z ! o!r "o2 :]eas 
on ! previ\s night !y _h appe>$ ne>ly ( 
equal magnitude4 ,i !re=e conclud$1 &   
decid$ unhesitat+ly1 t !re are ?ree />s 
9 ! heav5s mov+ ab\t ,jupit]1 z ,v5us & 
,m]cury r\nd ! ,sun2 :i* at l5g? 0      
e/abli%$ z cle> z daylight by num]\s o!r
 subsequ5t obs]vations4 ,^! obs]vations 

also e/abli%$ t !re are n only ?ree1 b  
f\r1 erratic sid]eal bodies p]=m+ _!    
revolutions r\nd ,jupit]1 obs]vations ( 
^: *anges ( position made ) m exactness 
on succe$+ nights ! foll[+ acc\nt w     
supply4 ,i h measur$ also ! int]vals    
betwe5 !m ) ! telescope 9 ! mann]       
already expla9$4 ,besides ?is1 ,i h giv5
 ! times ( obs]vation1 especially :5    
sev]al 7 made 9 ! same night1 = !       
revolutions ( ^! planets are s swift t  
an obs]v] may g5]ally get diff]5ces (   
position e h\r4  ,jan4 #ab4--;,at ! fir/
 h\r ( ! next night ,i saw ^! heav5ly   
bodies arrang$ 9 ?is mann] 7,fig4 #e74  
,! satellite#af fur!/ to ! ea/ 0 great] 
?an ! satellite fur!/ to ! we/2 b bo? 7 
v conspicu\s & bright2 ! di/ance ( ea*  
"o f ,jupit] 0 two m9utes4 ,a ?ird      
satellite1 c]ta9ly n 9 view be=e1 began 
to appe> at ! ?ird h\r2 x ne>ly t\*$    
,jupit] on ! ea/ side1 & 0 exce$+ly     
small4 ,!y 7 all arrang$ 9 ! same       
/raight l9e1 along ! ecliptic4      #af 
,galileo cont9ues to call ^! bodies />s1

 p]haps     mean+ 8,m$icean />s10       
?r\gh\t ! description ( _!              
configurations1 b z he _h n[ detect$ _! 
nature1 x is m     conv5i5t to call !m  
satellites1 ! t]m introduc$ by ,kepl]4  
,jan4 #ac4--;,= ! fir/ "t f\r satellites
 7 9 view 9 ! foll[+ position ) reg>d to
 ,jupit] 7,fig4 #f74  ,!re 7 ?ree to !  
we/1 & "o to ! ea/2 !y made a /raight   
l9e ne>ly1 b ! middle satellite ( ^? to 
! we/ deviat$ a little f ! /raight l9e  
t[>ds ! nor?4 ,! satellite fur!/ to !   
ea/ 0 at a di/ance ( #b f ,jupit]2 !re 7
 int]vals ( #a only betwe5 ,jupit] & !  
ne>e/ satellite1 & betwe5 ! satellites  
!mselves1 we/ ( ,jupit]4 ,all !         
satellites appe>$ ( ! same size1 & ?\gh 
small !y 7 v brilliant1 & f> out%one !  
fix$ />s ( ! same magnitude4  ,jan4     
#ad4--,! wea!r 0 cl\dy4  ,jan4          
#ae4--;,at ! ?ird h\r ( ! night ! f\r   
satellites 7 9 ! /ate depict$ 9 ! next  
diagram 7,fig4 #g7 ) ref]5ce to ,jupit]4
  ,all 7 to ! we/1 & arrang$ ne>ly 9 !  
same /raight l9e2 b ! satellite :i*     

c\nt$ ?ird f ,jupit] 0 rais$ a little to
 ! nor?4 ,! ne>e/ to ,jupit] 0 ! smalle/
 ( all2 ! re/ appe>$ l>g] & 9 ord] (    
magnitude2 ! int]vals betwe5 ,jupit] & !
 ?ree ne>e/ satellites 7 all equal1 & 7 
( ! magnitude ( #b ea*2 b ! satellite   
fur!/ to ! we/ 0 di/ant #d f ! satellite
 ne>e/ to x4 ,!y 7 v brilliant1 & n at  
all tw9kl+1 z !y h always appe>$ bo?    
be=e & s9ce4 ,b at ! sev5? h\r !re 7    
only ?ree satellites1 pres5t+ ) ,jupit] 
an appe>ance ( ! foll[+ k9d 7,fig4 #h74 
,!y 71 t is to say1 9 ! same /raight l9e
 to a hair2 ! ne>e/ to ,jupit] 0 v      
small1 & di/ant f ! planet #c2 ! di/ance
 ( ! second f ?is "o 0 #a2 & ( ! ?ird f 
! second #d #cj4 ,b aft] ano!r h\r ! two
 middle satellites 7 /ill ne>]1 = !y 7  
only #cj1 or less1 ap>t4  ,jan4         
#af4--;,at ! fir/ h\r ( ! night ,i saw  
?ree satellites arrang$ 9 ?is ord]      
7,fig4 #i74 ,jupit] 0 betwe5 two ( !m1  
:i* 7 at a di/ance ( #j #dj f ! planet  
on ei!r side1 & ! ?ird 0 we/ ( ,jupit]  
at a di/ance ( #h4 ,! satellites ne> to 

,jupit] appe>$ bright] ?an ! satellite  
fur!r (f1 b n l>g]4  ,jan4 #ag1 aft]    
sunset #j h\rs #cj m9utes1 !            
configuration 0 ( ?is k9d 7,fig4 #aj74  
,!re 0 "o satellite only to ! ea/1 at a 
di/ance ( #c f ,jupit]2 to ! we/        
likewise !re 0 only "o satellite1 di/ant
 #aa f ,jupit]4 ,! satellite on ! ea/   
appe>$ twice z l>ge z ! satellite to !  
we/2 & !re 7 no m ?an ^! two4 ,b f\r    
h\rs aft]1 t is1 ne>ly at ! fif? h\r1 a 
?ird satellite began to em]ge on ! ea/  
side1 :i*1 be=e its appe>ance1 z ,i ?9k1
 _h be5 jo9$ ) ! =m] ( ! two o!r        
satellites1 & ! position 0 ( ?is k9d    
7,fig4 #aa74 ,! middle satellite 0 v ne>
 inde$ to ! satellite on ! ea/1 & 0 only
 #bj f x2 & 0 a little t[>ds ! s\? ( !  
/raight l9e drawn ?r\gh ! two extreme   
satellites & ,jupit]4  ,jan4 #ah1 at #j 
h4 #bj m4 aft] sunset1 ! appe>ance 0 su*
 z ?is 7,fig4 #ab74 ,! satellite to !   
ea/ 0 l>g] ?an ! we/]n "o1 & 0 at a     
di/ance f ,jupit] ( #h1 ! we/]n "o be+  
at a di/ance ( #aj4  ,jan4 #ai4--;,at ! 

second h\r ( ! night ! relative position
 ( ! satellites 0 su* z ?is 7,fig4 #ac72
 t is1 !re 7 ?ree satellites exactly 9 a
 /raight l9e ) ,jupit]1 "o to ! ea/1 at 
a di/ance ( #f f ,jupit]2 betwe5 ,jupit]
 & ! fir/ satellite to ! we/ 9 ord]1 !re
 0 an int]val ( #e2 ?is satellite 0 #d  
(f ! o!r "o m to ! we/4 ,at t "t ,i 0   
d\btful :e!r or no !re 0 a satellite    
betwe5 ! satellite to ! ea/ & ,jupit]1 b
 s v close to ,jupit] z almo/ to t\* !  
planet2 b at ! fif? h\r ,i saw ?is      
satellite di/9ctly1 by t "t occupy+     
exactly ! middle position betwe5 ,jupit]
 & ! ea/]n satellite1 s t !             
configuration 0 ?us 7,fig4 #ad74        
,moreov]1 ! satellite :i* _h j come into
 view 0 v small2 yet at ! six? h\r x 0  
ne>ly z l>ge z ! re/4  ,jan4 #bj3 #a h4 
#ae m4--,a simil> arrangem5t 0 se5      
7,fig4 #ae74 ,!re 7 ?ree satellites1 s  
small z sc>cely to be di/+ui%able2 _!   
di/ances f ,jupit]1 & f "o ano!r1 7 n m 
?an #a4 ,i 0 d\btful :e!r on ! we/]n    
side !re 7 two satellites or ?ree4 ,ab\t

 ! six? h\r !y 7 gr\p$ 9 ?is way 7,fig4 
#af74 ,! ea/]n satellite 0 twice z f>   
away f ,jupit] z be=e1 t is #b2 on !    
we/]n side1 ! satellite 9 ! middle 0    
di/ant f ,jupit] #j #dj1 & f ! satellite
 /ill fur!r to ! we/ #j #bj2 at l5g?1 at
 ! sev5? h\r1 ?ree satellites 7 se5 on !
 we/]n side 7,fig4 #ag74 ,! satellite   
ne>e/ to ,jupit] 0 di/ant f ! planet #j 
#bj2 betwe5 ?is "o & ! satellite fur!/  
to ! we/ !re 0 an int]val ( #dj1 b      
betwe5 ^! ano!r satellite 0 9 view      
slightly s\?w>d ( !m1 & n m ?an #aj (f !
 mo/ we/]ly satellite4  ,jan4 #ba3 #j h4
 #cj m4--,!re 7 ?ree satellites on ! ea/
 side2 ! satellites & ,jupit] 7 at equal
 di/ances ap>t 7,fig4 #ah74 ,! int]vals 
7 by e/imation #ej ea*4 ,!re 0 also "o  
satellite on ! we/1 di/ant #d f ,jupit]4
 ,! satellite on ! ea/ side ne>e/ to    
,jupit] 0 ! lea/ ( all4  ,jan4 #bb3 #b  
h4--,! gr\p+ ( ! satellites 0 simil>    
7,fig4 #ai74 ,!re 0 an int]val ( #e f ! 
satellite on ! ea/ to ,jupit]2 f ,jupit]
 to ! satellite fur!/ to ! we/ #g4 ,!   

two int]ior satellites on ! we/]n side 7
 #j #dj ap>t1 & ! satellite ne>] to     
,jupit] 0 #a f ! planet4 ,! inn]        
satellites 7 small] ?an ! out] ones1 b  
!y 7 situat$ all 9 ! same /raight l9e1  
along ! ecliptic1 except t ! middle ( ! 
?ree we/]n satellites 0 slightly to !   
s\? ( x1 b at ! six? h\r ( ! night !y   
appe>$ 9 ?is position 7,fig4 #bj74 ,!   
satellite on ! ea/ 0 v small1 at a      
di/ance f ,jupit] ( #e z be=e2 b ! ?ree 
satellites on ! we/ 7 sep>at$ by equal  
di/ances f ,jupit] & f ea* o!r2 & !     
int]vals 7 ne>ly #a #bj ea*4 ,!         
satellite ne>e/ ,jupit] appe>$ small]   
?an ! o!r two on ! same side1 b !y all  
appe>$ arrang$ exactly 9 ! same /raight 
l9e4  ,jan4 #bc1 at #j h4 #dj m4 aft]   
sunset1 ! gr\p+ ( ! satellites 0 ne>ly  
aft] ?is fa%ion 7,fig4 #ba74 ,!re 7 ?ree
 satellites ) ,jupit] 9 a /raight l9e   
along ! ecliptic1 z !y always h be52 two
 7 on ! ea/ ( ! planet1 "o on ! we/2 !  
satellite fur!/ to ! ea/ 0 #g f ! next  
"o1 & ?is satellite #b #dj f ,jupit]2   

,jupit] 0 #c #bj f ! satellite on ! we/2
 & !y 7 all ( ne>ly ! same size4 ,b at !
 fif? h\r ! two satellites :i* _h be5   
previ\sly ne> ,jupit] 7 no long]        
visible1 be+1 z ,i suppose1 hidd5 beh9d 
,jupit]1 & ! appe>ance pres5t$ 0 su* z  
?is 7,fig4 #bb74  ,jan4 #bd4--,?ree     
satellites1 all on ! ea/ side1 7        
visible1 & ne>ly1 b n q1 9 ! same       
/raight l9e ) ,jupit]1 = ! satellite 9 !
 middle 0 slightly to ! s\? ( x 7,fig4  
#bc74 ,! satellite ne>e/ to ,jupit] 0 #b
 di/ant f ! planet2 ! next 9 ord] #j #cj
 f ?is satellite1 & ! ?ird 0 #i fur!r (f
 /ill2 !y 7 all v bright4 ,b at ! six?  
h\r two satellites only pres5t$ !mselves
 to view 9 ?is position1 namely 9 ! same
 /raight l9e ) ,jupit] exactly1 & !     
di/ance ( ! ne>e/ to ! planet 0 l5g!n$  
to #c2 ! next 0 #b fur!r (f1 & unless ,i
 am mi/ak51 ! two satellites previ\sly  
obs]v$ 9 ! middle _h come toge!r1 &     
appe>$ z "o4  ,jan4 #be1 at #a h4 #dj   
m41 ! satellites 7 gr\p$ ?us 7,fig4     
#bd74 ,!re 7 only two satellites on !   

ea/ side1 & ^! 7 r l>ge4 ,! satellite   
fur!/ to ! ea/ 0 #e f ! satellite 9 !   
middle1 & x 0 #f f ,jupit]4  ,jan4 #bf1 
at #j h4 #dj m41 ! relative positions ( 
! satellites 7 ?us 7,fig4 #be74 ,?ree   
satellites 7 9 view1 ( :i* two 7 ea/ & !
 ?ird we/ ( ,jupit]2 ?is "o 0 di/ant #c 
f ! planet4 ,on ! ea/ side ! satellite 9
 ! middle 0 at a di/ance ( #e #bj2 !    
fur!r satellite 0 #f beyond2 !y 7       
arrang$ 9 a /raight l9e1 & 7 ( ! same   
size4 ,at ! fif? h\r ! arrangem5t 0     
ne>ly ! same1 ) ?is diff]5ce only1 t !  
f\r? satellite 0 em]g+ on ! ea/ side ne>
 ,jupit]4 ,x 0 small] ?an ! re/1 & 0 !n 
at a di/ance ( #j #cj f ,jupit]2 b 0    
rais$ a little above ! /raight l9e t[>ds
 ! nor?1 z ! accompany+ figure %[s      
7,fig4 #bf74  ,jan4 #bg1 #a h4 aft]     
sunset1 a s+le satellite only 0 9 view1 
& t on ! ea/ side ( ,jupit] 9 ?is       
position 7,fig4 #bg74 ,x 0 v small1 & at
 a di/ance ( #g f ,jupit]4  ,jan4 #bh & 
#bi4--,ow+ to ! int]v5tion ( cl\ds1 ,i  
c\ld make no obs]vation4  ,jan4         

#cj4--;,at ! fir/ h\r ( ! night !       
satellites 7 9 view1 arrang$ 9 ! foll[+ 
way 7,fig4 #bh74 ,!re 0 "o satellite on 
! ea/ side1 at a di/ance ( #b #cj f     
,jupit]2 & !re 7 two satellites on !    
we/1 ( :i* ! "o ne>] to ,jupit] 0 #c (f 
! planet1 & ! o!r satellite #a fur!r4 ,!
 places ( ! out] satellites & ,jupit] 7 
9 ! same /raight l9e2 b ! satellite 9 ! 
middle 0 a little above x to ! nor?4 ,! 
satellite fur!/ to ! we/ 0 small] ?an ! 
re/4  ,on ! la/ day ( ! mon?1 at !      
second h\r1 two satellites on ! ea/ side
 7 visible1 & "o on ! we/ 7,fig4 #bi74  
,( ! satellites ea/ ( ! planet1 ! "o 9 !
 middle 0 #b #bj di/ant f ,jupit]2 & !  
satellite fur!r to ! ea/ 0 #j #cj f !   
middle satellite2 ! satellite on ! we/ 0
 at a di/ance ( #aj f ,jupit]4 ,!y 7 9 !
 same /raight l9e ne>ly1 & w\ld h be5   
exactly s1 only ! satellite on ! ea/    
ne>e/ to ,jupit] 0 rais$ a little t[>ds 
! nor?4 ,at ! f\r? h\r1 ! two satellites
 on ! ea/ 7 /ill ne>] toge!r1 = !y 7    
only #bj ap>t 7,fig4 #cj74 ,! we/]n     

satellite appe>$ r small 9 ^! two       
obs]vations4  ,feb4 #a4--;,at ! second  
h\r ( ! night ! arrangem5t 0 simil>     
7,fig4 #ca74 ,! satellite fur!/ to ! ea/
 0 at a di/ance ( #f f ,jupit]1 & !     
we/]n satellite #h4 ,on ! ea/ side !re 0
 a v small satellite1 at a di/ance ( #bj
 f ,jupit]4 ,!y made a p]fectly /raight 
l9e4  ,feb4 #b4--,! satellites 7 se5    
arrang$ ?us 7,fig4 #cb74 ,!re 0 "o only 
on ! ea/1 at a di/ance ( #f f ,jupit]4  
,jupit] 0 #d f ! ne>e/ satellite on !   
we/2 betwe5 ?is satellite & ! satellite 
fur!r to ! we/ !re 0 an int]val ( #h2 !y
 7 9 ! same /raight l9e exactly1 & 7    
ne>ly ( ! same magnitude4 ,b at ! sev5? 
h\r f\r satellites 7 !re--two on ea*    
side ( ,jupit] 7,fig4 #cc74 ,( ^!       
satellites1 ! mo/ ea/]ly 0 at a di/ance 
( #d f ! next2 ?is satellite 0 #a #dj f 
,jupit]2 ,jupit] 0 #f f ! ne>e/         
satellite on ! we/1 & ?is "o f !        
satellite fur!r to ! we/1 #h2 & !y 7 all
 alike 9 ! same /raight l9e1 drawn 9 !  
direction ( ! ,zodiac4  ,feb4 #c3 #g    

h4--,! satellites 7 arrang$ 9 ! foll[+  
way 7,fig4 #cd73--,! satellite on ! ea/ 
0 at a di/ance ( #a #cj f ,jupit]2 !    
ne>e/ satellite on ! we/1 #b1 & !re 0 a 
long di/ance1 #aj1 f ?is satellite to ! 
satellite fur!r to ! we/4 ,!y 7 exactly 
9 ! same /raight l9e1 & ( equal         
magnitude4  ,feb4 #d3 #b h4--,f\r       
satellites att5d$ ,jupit]1 two on ! ea/ 
& two on ! we/1 arrang$ 9 "o p]fectly   
/raight l9e1 z 9 ! adjo9+ figure 7,fig4 
#ce74 ,! satellite fur!/ to ! ea/ 0 at a
 di/ance ( #c f ! next satellite4 ,?is  
"o 0 #j #dj f ,jupit]2 ,jupit] #d f !   
ne>e/ satellite on ! we/2 & ?is "o f !  
satellite fur!r to ! we/ #f4 ,9         
magnitude !y 7 ne>ly equal2 ! satellite 
ne>e/ to ,jupit] 0 r small] 9 appe>ance 
?an ! re/4 ,b at ! sev5? h\r 7,fig4 #cf7
 ! ea/]n satellites 7 at a di/ance (    
only #j #cj ap>t4 ,jupit] 0 #b f ! ne>e/
 satellite on ! ea/2 & f ! satellite on 
! we/1 next 9 ord]1 #d2 ?is "o 0 di/ant 
#c f ! satellite fur!r to ! we/4 ,!y 7  
all equal 9 magnitude1 & 9 a /raight    

l9e1 drawn 9 ! direction ( ! ecliptic4  
,feb4 #e4--,! sky 0 cl\dy4  ,feb4       
#f4--,two satellites only appe>$1 )     
,jupit] betwe5 !m1 z is se5 9 !         
accompany+ figure 7,fig4 #cg74 ,!       
satellite on ! ea/ 0 #b f ,jupit]1 & t  
on ! we/ #c4 ,!y 7 9 ! same /raight l9e 
) ,jupit]1 & 7 equal 9 magnitude4  ,feb4
 #g4--,!re 7 two satellites by ! side ( 
,jupit]1 & bo? ( !m on ! ea/ ( ! planet1
 arrang$ 9 ?is mann] 7,fig4 #ch74 ,!    
int]vals betwe5 ! satellites & ,jupit] 7
 equal1 & ( #a ea*2 & a /raight l9e w\ld
 g ?r\gh !m & ! c5tre ( ,jupit]4  ,feb4 
#h3 #a h4--,?ree satellites 7 !re1 all  
on ! ea/ side ( ,jupit]1 z 9 ! diagram  
7,fig4 #ci74 ,! ne>e/ to ,jupit]1 a r   
small "o1 0 di/ant f ! planet #a #bj2 ! 
middle "o 0 #d f ?is satellite1 & 0 r   
l>ge2 ! satellite fur!/ to ! ea/1 a v   
small "o1 0 at a di/ance ( #j #bj f ?is 
satellite4 ,x 0 d\btful :e!r !re 0 "o   
satellite ne> to ,jupit] or two1 =      
sometimes x seem$ t !re 0 ano!r         
satellite by its side t[>ds ! ea/1      

wond]fully small1 & only #aj f x4 ,!y 7 
all situat$ at po9ts 9 a /raight l9e    
drawn 9 ! direction ( ! ,zodiac4 ,at !  
?ird h\r ! satellite ne>e/ to ,jupit] 0 
almo/ t\*+ ! planet1 = x 0 only di/ant  
#aj f x2 b ! o!rs _h become fur!r (f1 = 
! middle "o 0 #f f ,jupit]4 ,at l5g?1 at
 ! f\r? h\r1 ! satellite :i* 0 previ\sly
 ! ne>e/ to ,jupit] jo9$ ) ! planet &   
disappe>$4  ,feb4 #i3 #j h4 #cj m4--,!re
 7 two satellites on ! ea/ side (       
,jupit]1 & "o on ! we/1 9 an arrangem5t 
su* z ?is 7,fig4 #dj74 ,! satellite     
fur!/ to ! ea/1 :i* 0 a r small "o1 0   
di/ant #d f ! next satellite2 !         
satellite 9 ! middle 0 l>g]1 & at a     
di/ance ( #g f ,jupit]4 ,jupit] 0 di/ant
 #d f ! we/]n satellite1 :i* 0 a small  
"o4  ,feb4 #aj3 #a h4 #cj m4--,a pair ( 
satellites1 v small1 & bo? on ! ea/ ( ! 
planet1 7 visible1 9 ! foll[+ position  
7,fig4 #da74 ,! fur!r satellite 0 di/ant
 f ,jupit] #aj1 ! ne>] #j #bj1 & !y 7 9 
! same /raight l9e2 b at ! f\r? h\r !   
satellite ne>e/ to ,jupit] no long]     

appe>$1 & ! o!r seem$ s dim9i%$ t x c\ld
 sc>cely be kept 9 sight1 al?\gh !      
atmosph]e 0 q cle>1 & ! satellite 0     
fur!r f ,jupit] ?an be=e1 s9ce its      
di/ance 0 n[ #ab4  ,feb4 #aa3 #a        
h4--,!re 7 two satellites on ! ea/1 & "o
 on ! we/ 7,fig4 #db74 ,! we/]n         
satellite 0 at a di/ance ( #d f ,jupit]4
 ,! satellite on ! ea/1 ne>e/ to !      
planet1 0 likewise #d f ,jupit]2 b !    
satellite fur!r to ! ea/ 0 at a di/ance 
f ?is "o ( #h2 !y 7 fairly cle> to view1
 & 9 ! same /raight l9e2 b at ! ?ird h\r
 ! f\r? satellite 0 visible ne> to      
,jupit] on ! ea/1 less 9 magnitude ?an !
 re/1 sep>at$ f ,jupit] by a di/ance (  
#j #cj1 & slightly to ! nor? out ( !    
/raight l9e drawn ?r\gh ! re/ 7,fig4    
#dc74 ,!y 7 all v bright & extremely    
di/9ct1 b at #e h4 #cj m4 ! satellite on
 ! ea/ ne>e/ to ,jupit] _h mov$ fur!r   
away f ! planet1 & 0 occupy+ a position 
midway betwe5 ! planet & ! neighb\r+    
satellite fur!r to ! ea/4 ,!y 7 all 9 ! 
same /raight l9e exactly1 & ( ! same    

magnitude1 z may be se5 9 ! accompany+  
diagram 7,fig4 #dd74  ,feb4 #ab3 #j h4  
#dj m4--,a pair ( satellites on ! ea/1 a
 pair likewise on ! we/1 7 ne> ! planet 
7,fig4 #de74 ,! satellite on ! ea/ fur!/
 remov$ f ,jupit] 0 at a di/ance ( #aj1 
& ! fur!r ( ! satellites on ! we/ 0 #h  
(f4 ,!y 7 bo? fairly di/9ct4 ,! o!r two 
7 v ne> to ,jupit]1 & v small1          
especially ! satellite to ! ea/1 :i* 0  
at a di/ance ( #j #dj f ,jupit]4 ,!     
di/ance ( ! we/]n satellite 0 #a4 ,b at 
! f\r? h\r ! satellite :i* 0 ne>e/ to   
,jupit] on ! ea/ 0 visible no long]4    
,feb4 #ac3 #j h4 #cj m4--,two satellites
 7 visible 9 ! ea/1 two also 9 ! we/    
7,fig4 #df74 ,! satellite on ! ea/ ne>  
,jupit] 0 fairly di/9ct2 its di/ance f !
 planet 0 #b4 ,! satellite fur!r to !   
ea/ 0 less noticeable2 x 0 di/ant #d f !
 o!r4 ,( ! satellites on ! we/1 ! "o    
fur!/ f ,jupit]1 :i* 0 v di/9ct1 0 p>t$ 
f ! planet #d4 ,betwe5 ?is satellite &  
,jupit] int]v5$ a small satellite close 
to ! mo/ we/]ly satellite1 be+ n m ?an  

#j #c (f4 ,!y 7 all 9 ! same /raight    
l9e1 correspond+ exactly to ! direction 
( ! ecliptic4  ,feb4 #ae 7= on ! #ad? ! 
sky 0 cov]$ ) cl\ds71 at ! fir/ h\r1 !  
position ( ! satellites 0 ?us 7,fig4    
#dg72 t is1 !re 7 ?ree satellites on !  
ea/1 b none 7 visible on ! we/4 ,!      
satellite on ! ea/ ne>e/ to ,jupit] 0 at
 a di/ance ( #j #ej f ! planet2 ! next 9
 ord] 0 #j #bj f ?is satellite1 & !     
fur!/ to ! ea/ 0 #b f ! second          
satellite1 & x 0 l>g] ?an ! o!rs1 = ^?  
ne>] to ,jupit] 7 v small4 ,b ab\t !    
fif? h\r only "o ( ! satellites :i* _h  
be5 ne> to ,jupit] 0 to be se52 its     
di/ance f ,jupit] 0 #j #cj4 ,! di/ance (
 ! satellite fur!/ to ! ea/ f ,jupit] _h
 increas$1 = x 0 !n #d 7,fig4 #dh74 ,b  
at ! six? h\r1 besides ! two situat$ z j
 describ$ on ! ea/1 "o satellite 0      
visible t[>ds ! we/1 v small1 at a      
di/ance ( #b f ,jupit] 7,fig4 #di74     
,feb4 #af3 #f h4--,_! places 7 arrang$ z
 foll[s 7,fig4 #ej72 t is1 ! satellite  
on ! ea/ 0 #g f ,jupit]1 ,jupit] #e f ! 

next satellite on ! we/1 & ?is #c f !   
rema9+ satellite /ill fur!r to ! we/4   
,!y 7 all ( ! same magnitude ne>ly1 r   
bright1 & 9 ! same /raight l9e1         
correspond+ accurately to ! direction ( 
! ,zodiac4  ,feb4 #ag3 #a h4--,two      
satellites 7 9 view1 "o on ! ea/1 di/ant
 #c f ,jupit]2 ! o!r on ! we/1 di/ant   
#aj 7,fig4 #ea74 ,! latt] 0 some:at less
 ?an ! satellite on ! ea/2 b at ! six?  
h\r ! ea/]n satellite 0 ne>] to ,jupit]1
 be+ at a di/ance ( #j #ej1 & ! we/]n   
satellite 0 fur!r (f1 namely #ab4 ,at   
bo? obs]vations !y 7 9 ! same /raight   
l9e ) ,jupit]1 & 7 bo? r small1         
especially ! ea/]n satellite 9 ! second 
obs]vation4  ,feb4 #ah3 #a h4--,?ree    
satellites 7 9 view1 ( :i* two 7 on !   
we/ & "o on ! ea/2 ! di/ance ( ! ea/]n  
satellite f ,jupit] 0 #c1 & ( ! ne>e/   
satellite on ! we/ #b2 ! rema9+         
satellite1 /ill fur!r to ! we/1 0 #h f !
 middle satellite 7,fig4 #eb74 ,!y 7 all
 9 ! same /raight l9e exactly1 & ( ab\t 
! same magnitude4 ,b at ! second h\r !  

satellites ne>e/ to ! planet 7 at equal 
di/ances f ,jupit]1 = ! we/]n satellite 
0 n[ also #c f ! planet4 ,b at ! six?   
h\r ! f\r? satellite 0 visible betwe5 ! 
satellite on ! ea/ & ,jupit]1 9 ! foll[+
 configuration 7,fig4 #ec74 ,! satellite
 fur!/ to ! ea/ 0 at a di/ance ( #c f ! 
next 9 ord]2 ?is "o 0 at a di/ance ( #a 
#ej f ,jupit]2 ,jupit] 0 at a di/ance ( 
#c f ! next satellite on ! we/1 & ?is #g
 f ! satellite /ill fur!r to ! we/4 ,^! 
7 ne>ly equal 9 magnitude1 only !       
satellite on ! ea/ ne>e/ to ,jupit] 0 a 
little small] ?an ! re/1 & !y 7 all 9 ! 
same /raight l9e p>allel to ! ecliptic4 
,feb4 #ai3 #j h4 #dj m4--,two satellites
 only 7 9 view1 we/ ( ,jupit]1 r l>ge1 &
 arrang$ exactly 9 ! same /raight l9e ) 
,jupit]1 9 ! direction ( ! ecliptic     
7,fig4 #ed74 ,! ne>] satellite 0 at a   
di/ance ( #g f ,jupit] & ( #f f !       
satellite fur!r to ! we/4  ,feb4        
#bj4--,! sky 0 cl\dy4  ,feb4 #ba3 #a h4 
#cj m4--,?ree satellites1 r small1 7 9  
view1 plac$ ?us 7,fig4 #ee74 ,!         

satellite to ! ea/ 0 #b f ,jupit]2      
,jupit] 0 #c f ! next1 :i* 0 on ! we/2 &
 ?is "o 0 #g f ! satellite fur!r to !   
we/4 ,!y 7 exactly 9 ! same /raight l9e 
p>allel to ! ecliptic4  ,feb4 #be3 #a h4
 #cj m4 7= on ! ?ree previ\s nights !   
sky 0 ov]ca/74--,?ree satellites appe>$1
 two on ! ea/1 :i* 7 at a di/ance ( #d  
ap>t1 ! same z ! di/ance ( ! ne>]       
satellite f ,jupit]2 on ! we/ !re 0 "o  
satellite at a di/ance ( #b f ,jupit]4  
,!y 7 exactly 9 ! same /raight l9e 9 !  
direction ( ! ecliptic 7,fig4 #ef74     
,feb4 #bf3 #j h4 #cj m4--,a pair (      
satellites only 7 pres5t1 "o on ! ea/1  
di/ant #aj f ,jupit]2 ! o!r 0 on ! we/1 
at a di/ance ( #f 7,fig4 #eg74 ,! ea/]n 
satellite 0 slightly small] ?an ! we/]n4
 ,at ! fif? h\r ?ree satellites 7       
visible2 =1 besides ! two already       
notic$1 a ?ird satellite 0 9 view1 on ! 
we/1 ne> ,jupit]1 v small1 :i* previ\sly
 _h be5 hidd5 beh9d ,jupit]1 & x 0 at a 
di/ance ( #a f ! planet 7,fig4 #eh74  ,b
 ! satellite on ! ea/ 0 se5 to be fur!r 

(f ?an be=e1 be+ at a di/ance ( #aa f   
,jupit]4 ,on ?is night1 = ! fir/ "t1 ,i 
det]m9$ to obs]ve ! motion ( ,jupit] & !
 adjac5t planets 78 satellites7 along ! 
zodiac1 by ref]5ce to "s fix$ />2 = !re 
0 a fix$ /> 9 view1 ea/w>ds ( ,jupit]1  
at a di/ance ( #aa f ! satellite on !   
ea/1 & a little to ! s\?1 9 ! foll[+    
mann] 7,fig4 #ei74  ,feb4 #bg3 #a h4 #d 
m4--,! satellites appe>$ 9 ! foll[+     
configuration4 ,! satellite fur!/ to !  
ea/ 0 at a di/ance ( #aj f ,jupit]2 !   
next 9 ord] 0 ne> ,jupit]1 be+ at a     
di/ance ( #j #cj f ! planet4 ,! next    
satellite 0 on ! we/]n side1 at a       
di/ance ( #b #cj f ,jupit]2 & !         
satellite fur!r to ! we/ 0 at a di/ance 
( #a f ?is4 ,! two satellites ne> to    
,jupit] appe>$ small1 especially !      
satellite on ! ea/2 b ! satellites fur!/
 (f 7 v bright1 p>ticul>ly t on ! we/1 &
 !y made a /raight l9e 9 ! direction ( !
 ecliptic exactly4 ,! motion ( ! planets
 t[>ds ! ea/ 0 pla9ly se5 by ref]5ce to 
! a=esaid fix$ />1 = ,jupit] & 8        

att5dant satellites 7 ne>] to x1 z may  
be se5 9 ! accompany+ figure 7,fig4     
#fj74 ,at ! fif? h\r ! satellite on !   
ea/1 ne> to ,jupit]1 0 #a f ! planet4   
,feb4 #bh3 #a h4--,only two satellites 7
 visible1 "o on ! ea/1 at a di/ance ( #i
 f ,jupit]1 & ano!r on ! we/1 at a      
di/ance ( #b2 !y 7 bo? r bright1 & 9 !  
same /raight l9e ) ,jupit]1 & a /raight 
l9e drawn f ! fix$ /> p]p5dicul> to ?is 
/raight l9e fell ^u ! satellite on !    
ea/1 z 9 ! figure 7,fig4 #fa74 ,at !    
fif? h\r a ?ird satellite 0 se5 at a    
di/ance ( #b f ,jupit]1 on ! ea/1 9 !   
position %[n 9 ! figure 7,fig4 #fb74    
,m>* #a3 #j h4 #dj m4--,f\r satellites1 
all on ! ea/ ( ! planet1 7 se52 !       
satellite ne>e/ to ,jupit] 0 #b f !     
planet2 ! next #a f ?is2 ! ?ird 0 #j #bj
 f ! second1 & 0 bright] ?an ! o!rs2 & !
 satellite /ill fur!r to ! ea/ 0 at a   
di/ance ( #d f x1 & 0 small] ?an ! o!rs 
7,fig4 #fc74 ,!y made a /raight l9e v   
ne>ly1 only ! satellite ?ird f ,jupit] 0
 slightly above ! l9e4 ,! fix$ /> =m$ ) 

,jupit] & ! mo/ ea/]ly satellite an     
equilat]al triangle1 z 9 ! figure4  ,m>*
 #b3 #j h4 #dj m4--,?ree satellites 7 9 
att5dance1 two on ! ea/ & "o on ! we/1 9
 ! configuration %[n 9 ! diagram 7,fig4 
#fd74 ,! satellite fur!/ to ! ea/ 0 #g f
 ,jupit]2 f ?is satellite ! next 0      
di/ant #j #cj1 & ! satellite on ! we/ 0 
sep>at$ f ,jupit] by an int]val ( #b4 ,!
 satellites fur!/ (f 7 bright] & l>g]   
?an ! rema9+ satellite1 :i* appe>$ v    
small4 ,! satellite fur!/ to ! ea/ seem$
 to be rais$ a little t[>ds ! nor?1 out 
( ! /raight l9e drawn ?r\gh ! o!r       
satellites & ,jupit]4  ,! fix$ />       
already notic$ 0 at a di/ance ( #h f !  
we/]n satellite1 t is1 f ! p]p5dicul>   
drawn f t satellite to ! /raight l9e    
drawn ?r\gh all ! sy/em1 z %[n 9 !      
figure giv54  ,^! det]m9ations ( !      
motion ( ,jupit] & ! adjac5t planets 78 
satellites7 by ref]5ce to a fix$ />1 ,i 
h ?\ght well to pres5t to ! notice (    
a/ronom]s1 9 ord] t any "o may be able  
to und]/& f !m t ! movem5ts ( ^! planets

 7,jupit]'s satellites7 bo? 9 longitude 
& 9 latitude agree exactly ) ! motions (
 ,jupit] :i* are extract$ f tables4  ,^!
 are my obs]vations ^u ! f\r ,m$icean   
planets1 rec5tly discov]$ = ! fir/ "t by
 me2 & al?\gh x is n yet p]mitt$ me to  
d$uce by calculation f ^! obs]vations ! 
orbits ( ^! bodies1 yet ,i may be all[$ 
to make "s /atem5ts1 bas$ ^u !m1 well   
wor?y ( att5tion4  ,sid5ote3 ,d$uctions 
f ! previ\s obs]vations conc]n+ ! orbits
 & p]iods ( ,jupit]'s satellites4  ,&1 9
 ! fir/ place1 s9ce !y are sometimes    
beh9d1 sometimes be=e ,jupit]1 at l     
di/ances1 & )draw f ?is planet t[>ds !  
ea/ & t[>ds ! we/ only )9 v n>r[ limits 
( div]g5ce1 & s9ce !y accompany ?is     
planet alike :5 its motion is retrograde
 & direct1 x c be a matt] ( d\bt to no  
"o t !y p]=m _! revolutions ab\t ?is    
planet1 :ile at ! same "t !y all        
accompli% toge!r orbits ( twelve ye>s'  
l5g? ab\t ! c5tre ( ! _w4 ,moreov]1 !y  
revolve 9 unequal circles1 :i* is       
evid5tly ! conclusion to be drawn f !   

fact t ,i h nev] be5 p]mitt$ to see two 
satellites 9 conjunction :5 _! di/ance f
 ,jupit] 0 great1 :]eas ne> ,jupit] two1
 ?ree1 & sometimes all 7f\r71 h be5 f\nd
 closely pack$ toge!r4 ,moreov]1 x may  
be detect$ t ! revolutions ( !          
satellites :i* describe ! smalle/       
circles r\nd ,jupit] are ! mo/ rapid1 = 
! satellites ne>e/ to ,jupit] are (t5 to
 be se5 9 ! ea/1 :5 ! day be=e !y h     
appe>$ 9 ! we/1 & contr>iwise4 ,also !  
satellite mov+ 9 ! greate/ orbit seems  
to me1 aft] c>efully weigh+ ! occasions 
( its return+ to positions previ\sly    
notic$1 to h a p]iodic "t ( half a      
mon?4#ag ,besides1 we h a notable &     
spl5did argum5t to remove ! scruples (  
^? :o c tol]ate ! revolution ( ! planets
 r\nd ! ,sun 9 ! ,cop]nican sy/em1 yet  
are s di/urb$ by ! motion ( "o ,moon    
ab\t ! ,e>?1 :ile bo? accompli% an orbit
 ( a ye>'s l5g? ab\t ! ,sun1 t !y       
consid] t ?is !ory ( ! con/itution ( !  
univ]se mu/ be upset z impossible2 = n[ 
we h n "o planet only revolv+ ab\t      

ano!r1 :ile bo? trav]se a va/ orbit ab\t
 ! ,sun1 b our s5se ( sight pres5ts to u
 f\r satellites circl+ ab\t ,jupit]1 l !
 ,moon ab\t ! ,e>?1 :ile ! :ole sy/em   
travels ov] a mighty orbit ab\t ! ,sun 9
 ! space ( twelve ye>s4      #ag ,9 !   
edition ( ,galileo's works publi%$ at   
,flor5ce1     #ahed1 !re are giv5 !     
tables ( ! h\rly movem5ts ( !           
satellites ( ,jupit]1 f :i* ,galileo    
det]m9$ _! p]iods     ( revolution4 ,9 !
 beg9n+ ( 8 treatise on float+ bodies1  
,discorso intorno i ,galleggianti1      
#afaa-ab1 ,galileo gives ! times     (  
rotation z approximately1 7i47 #a d4    
#ah-a_/b h42 7ii47 #c d4     #ac-a_/c   
h42 7iii47 #g d4 #d h42 7iv47 #af d4 #ah
 h42 he also publi%$     configurations 
( ! satellites calculat$ = ,m>*1 ,april1
     & a "p ( ,may #afac4 ,! p]iodic    
times ( ! satellites1 z     correct$ by 
lat] obs]v]s1 are1 7i47 #a d4 #ah h4 #bh
 m42 7ii47 #c     d4 #ac h4 #ae m42     
7iii47 #g d4 #c h4 #dc m42 7iv47 #af d4 
#af h4 #cb m4  ,sid5ote3 ,explanation ( 

! v>iations 9 brightness ( ,jupit]'s    
satellites4  ,la/ly1 ,i mu/ n pass ov] !
 consid]ation ( ! reason :y x happ5s t !
 ,m$icean />s1 9 p]=m+ v small          
revolutions ab\t ,jupit]1 seem sometimes
 m ?an twice z l>ge z at o!r times4 ,we 
c by no means look = ! explanation 9 !  
mi/s ( ! ,e>?'s atmosph]e1 = !y appe>   
increas$ or dim9i%$1 :ile ! discs (     
,jupit] & neighb\r+ fix$ />s are se5 q  
unalt]$4 ,t !y approa* & rec$e f ! ,e>? 
at ! po9ts ( _! revolutions ne>e/ to &  
fur!/ f ! ,e>? to su* an ext5t z to     
acc\nt = s great *anges seems altoge!r  
unt5able1 = a /rict circul> motion c by 
no means %[ ^? ph5om5a2 & an elliptical 
motion 7:i* 9 ?is case w\ld be ne>ly    
rectil9e>7 seems to be bo? unt5able & by
 no means 9 h>mony ) ! ph5om5a obs]v$4  
,b ,i gladly publi% ! explanation :i*   
has occurr$ to me ^u ?is subject1 &     
submit x to ! judgm5t & criticism ( all 
true philosoph]s4 ,x is c]ta9 t :5      
atmosph]ic mi/s int]v5e ! ,sun & ,moon  
appe> l>g]1 b ! fix$ />s & planets less 

?an !y really are2 h5ce ! =m] lum9>ies1 
:5 ne> ! horizon1 are l>g] ?an at o!r   
times1 b />s appe> small]1 & are        
frequ5tly sc>cely visible2 also !y are  
/ill m dim9i%$ if ^? mi/s are ba!d 9    
light2 s />s appe> v small by day & 9 ! 
twilight1 b ! ,moon does n appe> s1 z ,i
 h previ\sly rem>k$4 ,moreov]1 x is     
c]ta9 t n only ! ,e>?1 b also ! ,moon1  
has its own vapor\s sph]e envelop+ x1 = 
! reasons :i* ,i h previ\sly m5tion$1 & 
especially = ^? :i* %all be /at$ m fully
 9 my ,sy/em2 & we may consi/5tly decide
 t ! same is true ) reg>d to ! re/ ( !  
planets2 s t x seems to be by no means  
an unt5able op9ion to place r\nd ,jupit]
 also an atmosph]e d5s] ?an ! re/ ( !   
e!r1#ah ab\t :i*1 l ! ,moon ab\t ! sph]e
 ( ! elem5ts1 ! ,m$icean planets        
7,jupit]'s satellites7 revolve2 & t by !
 int]v5tion ( ?is atmosph]e !y appe>    
small] :5 !y are 9 apogee2 b :5 9       
p]igee1 ?r\gh ! abs5ce or att5uation ( t
 atmosph]e1 !y appe> l>g]4 ,want ( "t   
prev5ts my go+ fur!r into ^! matt]s2 my 

read]s may expect fur!r rem>ks ^u ^!    
subjects 9 a %ort "t4      #ah ,mod]n   
a/ronom]s agree 9 assign+ an atmosph]e  
to     ,jupit]1 b consid] x n ext5sive  
en\gh to affect !     brightness ( !    
satellites4--7,,webb1 ,cele/ial ,objects
 = ,common     ,telescopes47 ,_!        
absolute magnitudes are diff]5t1 & _!   
surfaces h be5 obs]v$ to be obscur$ by  
spots1 :i* may     acc\nt = ! v>iations 
( _! brightness4 ,^! spots1 l     ! lun>
 spots1 are probably due to v>iations ( 
reflective     p[] at diff]5t p>ts ( _! 
surfaces1 = z !y always     turn ! same 
face to ,jupit]1 !y pres5t diff]5t      
portions (     _! surfaces to u         
p]iodically1 & x has be5 asc]ta9$     by
 obs]vation t 8^! fluctuations 9 _!     
brightness are     p]iodical1 dep5d+ on 
_! position ) respect to !              
,sun40--7,,h]s*el1 ,outl9es ( ,a/ronomy2
 ,,arago1 ,a/ronomie     ,populaire1    
#ahed47  ,orig9al ,configurations (     
,jupit]'s ,satellites obs]v$ by ,galileo
 9 ! mon?s ( ,janu>y1 ,febru>y1 & ,m>*  

#afaj1 & publi%$ ) ! #a/ edition ( 8    
book ,sid]eus ,nuncius1 ,v5ice1 #afaj4  
----------------------------------------
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----------------------         ,a ,,"p  
,,( ,,! ,,preface ,,to     ,,kepl]',s   
,,dioptrics      ,,=m+      ,a          
,,cont9uation ,,( ,,galileo',s          
,,sid]eal ,,mess5g]4       ,9 ! preface 
to ,kepl]'s ,dioptrics !re are introduc$

 lett]s     ( ,galileo ab\t ! new &     
a/oni%+ discov]ies :i* he     _h made 9 
! heav5s by ! aid ( ! telescope s9ce !  
publication ( 8 "w1 ,! ,sid]eal         
,mess5g]4 ,! portion     ( ! preface :i*
 ref]s to ,galileo1 conta9+ ^! lett]s   
& ,kepl]'s rem>ks ^u !m1 is add$ "h1 z  
cont9u+ !     orig9al acc\nt (          
,galileo's a/ronomical discov]ies4      
,extract f ! ,preface ( ,kepl]'s        
,dioptrics4 ,augsburg1 #afaa4           
,sid5ote3 ,kepl] rem>ks on ! importance 
( ! application ( ! telescope to        
a/ronomical inve/igations z indicat$ by 
,galileo's discov]ies1 publi%$ 9 8      
,sid]eal ,mess5g]4  8,! ,sid]eal        
,mess5g]0 ( ,galileo has be5 = a long "t
 9 ev]ybody's h&s1 also my 8,discussion1
 su* z x is1 ) ?is ,mess5g]10 & my      
,brief ,n>rative 9 confirmation (       
,galileo's ,sid]eal ,mess5g]1 s any     
read] may briefly weigh ! *ief po9ts ( t
 ,mess5g] & see ! nature & ! value ( !  
discov]ies made by ! aid ( ! telescope1 
! !ory ( :i* ,i am int5d+ to demon/rate 

9 ?is treatise4 ,actual sight te/ifi$ t 
!re is a c]ta9 bright heav5ly body :i*  
we call ! ,moon4 ,x 0 demon/rat$ f !    
laws ( optics t ?is body is r\nd2 also  
,a/ronomy1 by "s argum5ts f\nd$ ^u      
optics1 _h built up ! conclusion t its  
di/ance f ! e>? is ab\t sixty           
semi-diamet]s ( ! e>?4 ,v>i\s spots %[$ 
!mselves 9 t body2 & ! result 0 a dubi\s
 op9ion among a few philosoph]s1 d]iv$ f
 ,hecatu' acc\nt ( ! /ories ab\t ! isl& 
( ! ,hyp]boreans1#ai t ! reflect$ images
 ( m\nta9s & valleys1 sea & l&1 7 se5   
!re2 b n[ ! telescope places all ^!     
matt]s be=e our eyes 9 su* a way t he   
mu/ be an intellectual c[>d :o1 :ile    
enjoy+ su* a view1 /ill ?9ks t ! matt]  
is op5 to d\bt4 ,no?+ is m c]ta9 ?an t !
 s\!rn p>ts ( ! moon teem ) m\nta9s1 v  
_m 9 numb]1 & va/ 9 size2 & t ! nor!rn  
p>ts1 inasmu* z !y are l[]1 receive 9   
mo/ ext5sive lakes ! wat] fl[+ d[n f !  
s\?4 ,! conclusions :i* previ\sly ,p5a  
publi%$ z disclos$ by ! aid ( optics1   
/>t$ inde$ f c]ta9 slight supports1 r   

?an f\ndations1 af=d$ by actual sight1 b
 7 prov$ by long argum5ts dep5d+ "o ^u  
ano!r1 s t !y might be assign$ to human 
reason r ?an to sight2 b n[ our v eyes1 
z if a new door ( heav5 _h be5 op5$1 are
 l$ to ! view ( matt]s once hidd5 f !m4 
,b if x %\ld please any "o to exhau/ !  
=ce ( reason+ ^u ^! new obs]vations1 :o 
does n see h[ f> ! contemplation (      
nature w ext5d h] b\nd>ies1 :5 we ask1  
8,:at is ! use ( ! tracts ( m\nta9s &   
valleys1 & ! v wide expanse ( seas 9 !  
moon80 & 8,may n "s creature less noble 
?an man be imag9$ su* z might inhabit ^?
 tracts80      #ai ,diodorus ,siculus1  
ii4 #dg4  ,) no less c]ta9ty also d we  
decide by ! use ( ?is in/rum5t ev5 t    
fam\s "q1 :i*1 coeval ) philosophy      
itself1 is disput$ to ?is day by !      
noble/ intellects--,i mean1 :e!r ! e>? c
 move 7z ! !ory ( ! ,planets greatly    
requires7 )\t ! ov]?r[ ( all bodies t h 
weight1 or ! confusion ( ! motion ( !   
elem5ts8 ,= if ! e>? 7 bani%$ f ! c5tre 
( ! univ]se1 "s fe> le/ ! wat] %\ld     

leave ! orb ( ! e>? & fl[ to ! c5tre ( !
 univ]se2 & yet we see t 9 ! moon1 z    
well z 9 ! e>?1 !re is a quantity (     
moi/ure occupy+ ! sunk5 holl[s ( t      
globe2 & al?\gh ?is orb revolves        
actually 9 ! e!r1 & outside ! c5tres n  
m]ely ( ! univ]se1 b ev5 ( our e>?1 yet 
! mass ( wat] 9 ! moon is n at all h9d]$
 f cleav+ inv>iably to ! orb ( ! moon1 &
 t5d+ to ! c5tre ( ! body to :i* x      
belongs4 ,s1 by ?is in/ance ( ! ph5om5a 
( ! moon1 ! sci5ce ( optics am5ds !     
receiv$ !ory ( me*anics1 & confirms on  
?is po9t my introduction to my          
,comm5t>ies ^u ! ,motions ( ! ,planet   
,m>s4#bj      #bj ,kepl] says 9 8       
introduction to 8 ,comm5t>ies ^u     !  
,motions ( ! ,planet ,m>s1 t ! !ory (   
gravitation     dep5ds on c]ta9 axioms1 
"o ( :i* is t 8heavy bodies d     n t5d 
to ! c5tre ( ! univ]se1 suppos+ ! e>? to
 be     plac$ !re1 because t po9t is !  
c5tre ( ! univ]se1     b because x is ! 
c5tre ( ! e>?4 ,s1 :]ev] ! e>?     be   
set1 or :i!rsoev] x be transport$1 heavy

 bodies h a     cont9ual t5d5cy to x40  
,kepl]'s object 9 ?is "w 0 to           
correct ! me?ods = det]m9+ ! app>5t     
places ( !     planets accord+ to ! ?ree
 !ories !n curr5t--! ,ptolemaic1     !  
,cop]nican1 & t ( ,ty*o ,brahe4      ,9 
#aeic ! obs]v$ place ( ! planet ,m>s    
diff]$ by ne>ly     #e f ! place        
calculat$ = x4 ,kepl] accord+ly /udi$   
! motions ( ?is planet1 & 8by mo/       
labori\s demon/rations     & discussions
 ( _m obs]vations10 arriv$ at !         
conclusions     kn[n z ,kepl]'s fir/ &  
second laws2 accord+ to :i* !           
,cop]nican sy/em ( ecc5trics & epicycles
 0 replac$ by an     ellipse ^: c5tre & 
ecc5tricity 7 ! same z ! c5tre     &    
ecc5tricity ( ! ecc5tric 9 ! old] me?od1
 & ! ,sun     !re=e 0 9 "o ( ! foci4    
,also ! motion ( ! planet 9     its     
orbit 0 su* t equal areas 7 describ$    
ab\t ! ,sun by     ! radius vector ( !  
planet 9 equal times4--,,kepl]1         
,a/ronomia     ,nova  7,prague71 #afji4 
,! foll[]s ( ! ,samian philosophy 7= ,i 

may use ?is epi!t to designate !        
philosophy orig9at$ by ! ,samians1      
,py?agoras & ,ari/>*us7 h a /rong       
argum5t aga9/ ! app>5t immobility ( !   
e>? provid$ 9 ! ph5om5a ( ! moon4 ,= we 
are taught by optics t if any "o ( u 0 9
 ! moon1 to him ! moon1 8 abode1 w\ld   
seem q immovable1 b our e>? & sun & all 
! re/ ( ! heav5ly bodies movable2 = !   
conclusions ( sight are ?us relat$4     
,p5a has notic$ h[ a/ronom]s1 us+ !     
pr9ciples ( optics1 h by mo/ labori\s   
reason+ remov$ ! ,milky ,way f !        
elem5t>y univ]se1 :]e ,ari/otle _h plac$
 x1 into ! highe/ region ( ! e!r2 b n[1 
by ! aid ( ! telescope lately inv5t$1 ! 
v eyes ( a/ronom]s are conduct$ /raight 
to a ?or\gh survey ( ! sub/ance ( !     
,milky ,way2 & :oev] enjoys ?is sight is
 compell$ to confess t ! ,milky ,way is 
no?+ else b a mass ( extremely small    
/>s4  ,aga91 up to ?is "t ! nature (    
nebul\s />s _h be5 entirely unkn[n2 b if
 ! telescope be direct$ to "o ( su*     
nebul\s balls1 z ,ptolemy calls !m1 x   

aga9 %[s1 z 9 ! case ( ! ,milky ,way1   
?ree or f\r v bright />s clu/]$ v close 
toge!r4  ,aga91 :o )\t ?is in/rum5t w\ld
 h believ$ t ! numb] ( ! fix$ />s 0 t5  
times1 or p]haps tw5ty times1 m ?an t   
:i* is giv5 9 ,ptolemy's description ( !
 fix$ />s8 ,& :5ce1 pray1 %\ld we seek =
 conclusive evid5ce ab\t ! end or b\nd>y
 ( ?is visible univ]se1 prov+ t x is    
actually ! sph]e ( ! fix$ />s1 & t !re  
is no?+ beyond1 except f ?is v discov]y 
by ! telescope ( ?is multitude ( fix$   
/>s1 :i* is1 z x 71 ! vault+ ( ! mobile 
univ]se8 ,aga91 h[ greatly an a/ronom]  
w\ld g wrong 9 det]m9+ ! magnitude ( !  
fix$ />s1 except he %\ld survey ! />s   
all ov] aga9 ) a telescope1 also may be 
se5 9 ,galileo's treatise1 & we w also  
h]eaft] produce 9 pro( a lett] f a      
,g]man a/ronom]4  ,b no words c express 
my admiration ( t *apt] ( ! ,sid]eal    
,mess5g] :]e ! /ory is told ( !         
discov]y1 by ! aid ( a v highly f9i%$   
telescope1 ( ano!r _w1 z x 71 9 ! planet
 ,jupit]4 ,! m9d ( ! philosoph] almo/   

reels z he consid]s t !re is a va/ orb1 
:i* is equal 9 mass to f\rte5 orbs l !  
e>? 7unless on ?is po9t ! telescope (   
,galileo %all %ortly reveal some?+ m    
exact ?an ! measurem5ts ( ,ty*o ,brahe7 
r\nd :i* circle f\r moons1 n unlike ?is 
moon ( ours2 ! sl[e/ revolv+ 9 ! space (
 f\rte5 ( our days1 z ,galileo has      
publi%$2 ! next to ?is1 by f> ! brighte/
 ( ! f\r1 9 ! space ( eight days1 z ,i  
detect$ 9 la/ ,april & ,may2 ! o!r two 9
 /ill %ort] p]iods4 ,& "h ! reason+ ( my
 ,comm5t>ies ab\t ! ,planet ,m>s1 appli$
 to a simil> case1 induces me to        
conclude also t ! actual orb ( ,jupit]  
rotates ) v great rapidity1 mo/ c]ta9ly 
fa/] ?an once 9 ! space ( "o ( our days2
 s t ?is rotation ( ! mighty orb ^u its 
own axis is accompani$ :]ev] x goes by !
 p]petual circuits ( ^? f\r moons4      
,moreov]1 ?is sun ( ours1 ! common s\rce
 ( heat & light = ?is t]re/rial _w z    
well z = t _w ( ,jupit]1 :i* we consid] 
to be ( ! angul> magnitude ( #cj at mo/1
 !re sc>cely subt5ds m ?an #f or #g1 &  

is f\nd aga9 9 ! same position among !  
fix$ />s1 hav+ complet$ ! zodiac 9 !    
int]val1 aft] a p]iod ( twelve ( our    
ye>s4#ba ,accord+ly1 ! creatures :i*    
live on t orb ( ,jupit]1 :ile !y        
contemplate ! v swift c\rses ( ^? f\r   
moons among ! fix$ />s1 :ile !y behold  
!m & ! sun ris+ & sett+ day by day1 w\ld
 swe> by ,jupit]-9-/one1 l ! ,romans 7= 
,i h lately return$ f ^? p>ts71 t _! orb
 ( ,jupit] rema9s immovable 9 "o spot1 &
 t ! fix$ />s & ! sun1 :i* are ! bodies 
really at re/1 no less ?an ^? f\r moons 
( !irs1 revolve r\nd t abode ( !irs )   
manifold v>iety ( motions4 ,& f ?is     
in/ance n[1 mu* m ?an be=e f ! in/ance (
 ! moon1 any foll[] ( ! ,samian         
philosophy w le>n :at reply may be made 
to any "o object+ to ! !ory ( ! motion (
 ! e>? z absurd1 & alleg+ ! evid5ce (   
our sight4 ,o telescope1 in/rum5t ( mu* 
k1 m preci\s ?an any sceptre6 ,is n he  
:o holds !e 9 8 h& made k+ & "l ( !     
works ( ,god8 ,truly      8,all t is    
ov]head1 ! mighty orbs     ,) all _!    

motions1 ?\ do/ subjugate     ,to man's 
intellig5ce40  ,if !re is any "o 9 "s   
degree fri5dly to ,cop]nicus & ! lights 
( ! ,samian philosophy1 :o f9ds ?is     
difficulty only1 t he d\bts h[ x c      
happ51 suppos+ ! e>? to p]=m aga9 & aga9
 h] c\rse among ! planets ?r\gh ! e!real
 pla9s1 t ! moon %\ld keep s con/antly  
by h] side1 l an insep>able companion1 &
 at ! same "t fly r\nd & r\nd ! actual  
orb ( ! e>?1 j l a fai?ful dog :i* goes 
r\nd & r\nd 8 ma/] on "s j\rney1 n[     
runn+ 9 front1 n[ deviat+ to ?is side or
 t1 9 ev]-v>y+ mazes1 let him look at ! 
planet ,jupit]1 :i*1 z ?is telescope    
%[s1 c]ta9ly c>ries 9 its tra9 n "o su* 
companion only1 l ! e>?1 z ,cop]nicus   
%[$1 b actually f\r1 t nev] leave x1    
?\gh all ! "t ha/5+ ea* 9 its own orbit4
      #ba ,! degree ( accuracy atta9$ by
 ,kepl] & ,galileo )     _! imp]fect    
in/rum5ts w be appreciat$ by comp>+     
^! /atem5ts ) ! det]m9ations ( lat]     
a/ronom]s4     ,jupit] is ab\t #acjj    
times ! size ( ! ,e>?4 ,its diamet] is  

ab\t #hg1jjj miles2 "t ( rotation1 #i h4
 #ee m4 #ba sec42 "t (     revolution1  
#dccc days ne>ly4 ,! angul> diamet] ( ! 
sun1 se5     f ,jupit]1 is betwe5 #f &  
#g4 ,! times ( revolution ( !     f\r   
satellites are1 z already giv53 7i47 #a 
d4 #ah h4 #bh m41 7ii47     #c d4 #ac h4
 #ae m41 7iii47 #g d4 #c h4 #dc m41     
7iv47 #af d4 #af h4 #cb m4  ,b en\gh has
 be5 said ab\t ^! matt]s 9 my           
,discussion ) ! ,sid]eal ,mess5g]4 ,x is
 "t t ,i %\ld turn to ^? discov]ies :i* 
h be5 made s9ce ! publication (         
,galileo's ,sid]eal ,mess5g]1 & s9ce my 
,discussion ) x1 by means ( ?is         
telescope4  ,sid5ote3 ,galileo's        
discov]y ( ,saturn's r+ 7imp]fectly74   
,x is n[ j a ye> s9ce ,galileo wrote to 
,prague1 & gave full notice t he _h     
detect$ some?+ new 9 ! heav5s beyond 8  
=m] discov]ies2 & t !re might n be any  
"o :o1 ) ! int5tion ( detract+ f 8      
cr$it1 %\ld try to pass himself (f z an 
e>li] obs]v] ( ! ph5om5on1 ,galileo gave
 a c]ta9 space ( "t = ! publication ( ! 

new ph5om5a :i* any "o _h se52 he       
himself mean:ile describ$ 8 discov]y 9  
lett]s transpos$ 9 ?is mann]3 s m a i s 
m r m i l m e p o e t a l e u m i b u n 
e n u g t t a u i r a s4 ,out ( ^!      
lett]s ,i made an unc\? v]se :i* ,i     
ins]t$ 9 my ,%ort ,acc\nt 9 ! mon? (    
,septemb] ( la/ ye>3--      ,salve      
umbi/9eum#bb gem9atum ,m>tia proles4    
,hail1 tw9 companion%ip1 *ildr5 ( ,m>s4 
#bb ,umbi/9eum4 ,app>5tly ?is is "s     
,g]man ^w ) a     ,lat9 end+1 su* z     
um-bei-/ehn2 ,kepl] fanci$ t ,galileo   
_h discov]$ two satellites ( ,m>s4  ,b  
,i 0 a v long way f ! mean+ ( ! lett]s2 
x conta9$ no?+ to d ) ,m>s2 &1 n to     
deta9 y1 read]1 "h is ! solution ( !    
riddle 9 ! words ( ,galileo himself1 !  
au?or ( x3#bc--      8,di ,fir5ze li #ac
 di ,novembre #afaj4--,ma pass&o ad     
altro1 giac*     il ,sig4 ,kepl]o ha 9  
que/a sua ultima n>razione /ampate le   
lett]e *e io m&ai traspo/e a ,vo/ra     
,signoria ,illu/rissima     e           
,rev]5dissima v55domi anco significato  

come ,sua ,mae/     ne desid]a il s5so1 
ecco *e io lo m&o a ,vo/ra ,signoria    
,illu/rissima p] p>ticip>lo con ,sua    
,mae/ col ,sig4 ,kepl]o e     con *i    
piac] a ,vo/ra ,signoria ,illu/rissima  
bram&o io *e     lo sappia ognuno4 ,le  
lett]e dunque comb9ate nel lor v]o s5so 
dicono cos1          ,altissimum        
planetam t]gem9um obs]vavi4      ,que/o 
1 *e ,saturno con mia gr&issima         
ammirazione ho oss]vato     ess]e non   
una /ella sola1 ma tre insieme1 le quali
 quasi si     toccano2 e sono tr di loro
 totalm5te immobili1 e con/ituite     9 
que/a guisa oo4 ,quella di mezzo  assai 
pi gr&e delle     lat]ali2 sono situate 
una da ori5te1 l'altra da occid5te1     
nella     m$esima l9ea retta a capello2 
non sono giu/am5te secondo la           
dirittura del ,zodiaco1 ma l'occid5tale 
si eleva alquanto v]so     ,borea2 =se  
sono p>allele all',equ9oziale4 ,se si   
gu>d]anno     con un oc*iale *e non sia 
di gr&issima moltiplicazione1 non       
app>iranno tre /elle b5 di/9te1 ma p>r1 

*e ,saturno sia una     /ella lunghetta 
9 =ma di un'oliva1 cos1 4 ,ma s]v5dosi  
di un oc*iale *e moltipli*i pi di mille 
volte 9 sup]ficie1     si v$ranno tre   
globi di/9tissimi1 *e quasi si toccano1 
non     app>5do tr essi maggior         
divisione di un sottil filo oscuro4 ,or 
ecco trovata la corte a ,giove1 e due   
,s]vi a que/o ,vec*io *e     l'aiutano a
 camm9>e n mai se gli /accano dal       
fianco4 ,intorno     agli altri ,pianeti
 non ci  novit alcuna1 ec40      #bc ,! 
text ( ! f\r lett]s ( ,galileo foll[$ "h
 is t     giv5 9 ! edition ( ,galileo's 
works publi%$ at ,flor5ce1     #ahdb-ef2
 t 9 ! edition ( ,kepl]'s ,dioptrics1   
publi%$ at     ,augsburg1 #afaa1 is v   
inaccurate4 ,^! lett]s 7 writt5 to      
,giuliano de' ,m$ici1 ambassador ( !    
,gr&-,duke ( ,tuscany to !     ,emp]or  
,rudolf ,,ii4 at ,prague4  ,al?\gh ^!   
words diff] little f ,lat91 yet ,i w    
translate !m t no difficulty may h9d] my
 read] f foll[+ me4 ,?us !n ,galileo    
writes3--8,b to come n[ to my second    

topic4 ,s9ce ,kepl] has publi%$ 9 t     
rec5t #8,n>rative' ( 8 ! lett]s :i* ,i  
s5t z an anagram to y\r illu/ri\s       
,lord%ip1 & s9ce an intimation has be5  
giv5 me t 8 ,maje/y desires to be taught
 ! mean+ ( ^? lett]s1 ,i s5d x to y\r   
illu/ri\s ,lord%ip1 t y\r ,lord%ip may  
communicate x to 8 ,maje/y1 to ,kepl]1 &
 to any "o y\r ,lord%ip may wi%4  8,!   
lett]s :5 jo9$ toge!r z !y ought to be1 
say ?is1     #8,altissimum planetam     
t]gem9um obs]vavi1'     #8,i h obs]v$ ! 
mo/ di/ant ( ! planets to h a triple    
=m4'      8,= 9 tru? ,i h f\nd out ) !  
mo/ int5se surprise     t ! planet      
,saturn is n m]ely "o s+le />1 b ?ree   
/>s v close toge!r1 s mu* s t !y are all
 b 9     contact "o ) ano!r4 ,!y are q  
immovable ) reg>d to     ea* o!r1 & are 
arrang$ 9 ?is mann]1 oo4 ,! middle />   
( ! ?ree is by f> great] ?an ! two on   
ei!r side4 ,!y     are situat$ "o t[>ds 
! ea/1 ! o!r t[>ds ! we/1 9     "o      
/raight l9e to a hair's-bread?2 n1      
h[ev]1 exactly 9     ! direction ( !    

,zodiac1 = ! /> fur!/ to ! we/     rises
 some:at t[>ds ! nor?2 p]haps !y are    
p>allel to     ! equator4 ,if y look at 
!m ?r\gh a glass t does n     multiply  
mu*1 ! />s w n appe> cle>ly sep>ate f "o
     ano!r1 b ,saturn's orb w appe>     
some:at elongat$1 ( !     %ape ( an     
olive1 ?us1 4 ,b if y %\ld use a glass  
:i*     multiplies a surface m ?an a    
?\s& times1 !re w appe>     v di/9ctly  
?ree orbs1 almo/ t\*+ "o ano!r2 & !y    
w be ?\ght to be n f>!r ap>t ?an !      
bread? ( a v     f9e & sc>cely visible  
?read4 ,s y see a gu>d ( satellites     
has be5 f\nd = ,jupit]1 & = ! decrepit  
little old man two     s]vants to help 8
 /eps & nev] leave 8 side4 ,conc]n+ !   
re/ ( ! planets ,i h f\nd no?+ new40  ,s
 says ,galileo2 b if ,i may d s1 ,i w n 
make an old dot>d out ( ,saturn1 & two  
s]vants = him out ( 8 companion orbs1 b 
r out ( ^? ?ree unit$ bodies ,i w make a
 triple ,g]yon1 out ( ,galileo ,h]cules1
 & out ( ! telescope 8 club1 arm$ ) :i*1
 ,galileo has conqu]$ t mo/ di/ant ( !  

planets1 drawn x out ( ! fur!/ recesses 
( nature1 dragg$ x d[n to e>?1 & expos$ 
x to ! gaze ( u all4 ,x pleases me too1 
n[ t ! ne/ has be5 f\nd1 to consid] )   
curiosity :at k9d ( brood mu/ be 9 x1   
:at k9d ( life1 if !re be any life !re1 
betwe5 orbs :i* all b t\* ea* o!r two & 
two1 :]e n ev5                          
8a space     ,( sky ext5ds n m ?an ?ree 
ells wide10#bd  b :]e !re is sc>cely a  
*9k ( a nail's-bread? all r\nd4      #bd
 ,virgil1 ,eclog4 iii4 #aje4  ,d inde$ !
 a/rolog]s rightly ascribe to ,saturn ! 
gu>dian%ip ( m9]s1 :o1 accu/om$ to sp5d 
_! lives1 l moles1 und]gr\nd1 seldom    
brea! ! free air "u ! op5 sky8 ,al?\gh !
 d>kness "h is r m supportable ?an 9    
,saturn1 because ! sun1 :i* appe>s !re  
only z l>ge z ,v5us appe>s to u on !    
e>?1 cont9ually ca/s its rays ?r\gh !   
spaces betwe5 ! diff]5t orbs 9 su* a way
 t ^? inhabitants :o are situat$ on "o  
orb are cov]$ by ! o!r z by a ceil+2    
:ile ^? on ! latt] orb1 on ! top ( ?is  
ro( ( !irs1 expos$ z x is to ! full     

light ( ! sun1 receive a gl>e z if f v  
firebr&s4 ,b ,i mu/ draw 9 ! re9s & *eck
 my m9d 9 its enjoym5t ( ! free fields (
 e!r2 = fe>1 p]*ance1 lat] obs]vations  
%\ld report some?+ diff]5t f ! fir/     
acc\nt1 some?+ *ang$ 9 c\rse ( "t4#be   
#be ,! completion ( ,galileo's          
obs]vations on ,saturn dep5d$     on !  
improvem5t ( a/ronomical in/rum5ts1 z w 
be evid5t     f ! foll[+ sket*4 ,galileo
 made out ! fir/ indications     (      
,saturn's r+ 9 #afaj1 z n>rat$ 9 8      
lett]1 ) a p[]     ( ?irty2 b 9 ,decemb]
 #afab he wrote to "o ( 8 fri5ds1       
,m>co ,vels]i1 t he c\ld no long] see ^!
 indications1     & began to imag9e t 8 
telescope _h deceiv$ him1 &     app>5tly
 ab&on$ fur!r rese>*es4 ,hevelius 9     
#afdb saw     ! r+ m cle>ly1 b figur$ x 
z two cresc5ts atta*$     to ,saturn by 
_! cusps4 ,at l5g?1 9 #afec1 ,huygh5s   
provid$     himself ) a p[] ( "o hundr$1
 hav+ made ! l5ses )     8 own h&s1 &   
imm$iately discov]$ ! explanation ( !   
ph5om5a :i* _h baffl$ previ\s obs]v]s4  

,he publi%$ 8     explanation (         
,saturn's r+1 & 8 discov]y ( ! fir/     
satellite1 9 8 ,sy/ema ,saturnium1      
#afei4 ,cass9i1 ) /ill     m p[]ful     
in/rum5ts1 discov]$ f\r m satellites 9  
#afga1 #afgb1 #afhd4 ,sir ,william      
,h]s*el 9 #aghi detect$ two     m1 8:i* 
c only be se5 ) telescopes ( extraord9>y
     p[] & p]fection1 & "u ! mo/        
fav\rable atmosph]ic                    
circum/ances40--7,,h]s*el1 ,outl9es (   
,a/ronomy1  #edh47 ,& !     la/ ( !     
eight satellites 0 discov]$ 9 #ahdh by  
,lassell (     ,liv]pool1 & ,bond (     
,cambridge1 ,u4,s41 simultane\sly4  ,at 
! end ( 8 lett] ,galileo seem$ to ?9k t 
he _h come to ! end ( 8 reports ab\t !  
planets1 & obs]vations ( new ph5om5a    
respect+ !m1 b ev] on ! wat*1 t eye ( 81
 t "o n ( ,nature's mak+--,i mean 8     
telescope--9 a %ort "t made m           
discov]ies1 conc]n+ :i* read ! foll[+   
lett] ( ,galileo3--  ,sid5ote3 ,acc\nt (
 ,galileo's discov]y ( ! phases ( ,v5us4
      8,di ,fir5ze li #aa di ,decembre  

#afaj4--,/o con desid]io1 att5d5do      
la rispo/a a due mie scritte ultimam5te 
p] s5tire quello1 *e     av] detto il   
,sig4 ,kepl]o della /ravaganza di       
,saturno4 ,intanto     m&o a ,vo/ra     
,signoria ,illu/rissima e ,rev]5dissima 
la cifra     di un altro p>ticol>e      
oss]vato da me nuovam5te1 il quale si   
tira dietro la decisione di gr&issime   
controv]sie 9 ,a/ronomia1     ed 9      
p>ticol>e conti5e 9 se un gagli>do      
argom5to p] la     con/itutione         
,pitagorica e ,cop]nicana dell',univ]so2
 e a suo     tempo pubbli*] la          
decif]azione ed altri p>ticol>i4 ,sp]o  
*e     av] trovato il metodo p] def9ire 
i p]iodi dei quattro ,pianeti           
,m$icei1 /imati con gran ragione quasi  
inesplicabili dal ,sig4     ,kepl]o1 al 
quale piac]1 ec4      8,le lett]e       
traspo/e sono que/e3      8,haec        
immatura a me jam fru/ra leguntur1 o4y40
  ,:i* may be translat$ ?us3--      8,i 
am anxi\sly look+ = an answ] to my la/  
two lett]s1 t     ,i may le>n :at ,kepl]

 says ab\t ! m>vels ( ,saturn's orb4    
,9 ! meantime ,i s5d him a riddle       
conc]n+ a c]ta9 new &     spl5did       
obs]vation :i* t5ds to decide great     
controv]sies 9     a/ronomy2 &          
especially conta9s a f9e argum5t 9 fav\r
 ( !     ,py?agorean & ,cop]nican sy/em 
( ! univ]se4 ,at ! prop]     "t ,i w    
publi% ! solution ( ! riddle1 & "s o!r  
p>ticul>s4 ,i hope t ,i h f\nd a me?od (
 det]m9+ !     p]iodic times ( ! f\r    
,m$icean planets1 :i* ,kepl]1 n     )\t 
v good reason1 ?\ght inexplicable1 etc4 
8,! lett]s turn$ into an anagram1 are   
^!3      8,haec immatura a me jam fru/ra
 leguntur1 o4y40  ,s f> ,galileo4 ,b if1
 read]1 ?is lett] has fill$ y ) a desire
 to "k ! mean+ conta9$ 9 ^? lett]s1 !n y
 mu/ read ano!r lett] ( ,galileo :i*    
foll[s4  ,illu/ration3 ,fig4 #a4  ,e !  
,e>? 7c5tre ( univ]se74 ,s ! ,sun4 ,c   
c5tre ( ecc5tric4 ,d c5tre ( planet's   
epicycle4 ,,vv' /ation>y po9ts4 s v v'  
projections ( ,,svv' on ! ecliptic ( :i*
 ,e is ! c5tre4  ,illu/ration3 ,fig4 #b4

  ,s ! ,sun1 c5tre ( sol> sy/em4 v e    
positions ( planet & ,e>? at            
conjunction4 ,,vv' /ation>y po9ts (     
planet4 ,,ee' correspond+ positions ( ! 
,e>?4   ,b be=e y d s1 ,i %\ld l y to   
notice1 by ! way1 :at ,galileo says ab\t
 ! ,py?agorean & ,cop]nican sy/em ( !   
univ]se4 ,= he po9ts to my ,my/]y ( !   
,univ]se1#bf publi%$ f\rte5 ye>s ago1 9 
:i* ,i took ! dim5sions ( ! ,planet>y   
orbits accord+ to ! a/ronomy (          
,cop]nicus1 :o makes ! sun immovable 9 !
 c5tre1 & ! e>? movable bo? r\nd ! sun &
 ^u its own axis2 & ,i %[$ t ! diff]5ces
 ( _! orbits correspond$ to ! five      
regul> ,py?agorean figures1 :i* _h be5  
already di/ribut$ by _! au?or among !   
elem5ts ( ! _w1 ?\gh ! attempt 0        
admirable r ?an happy or legitimate1 & =
 :i* figures' sake ,euclid wrote ! :ole 
( 8 ,geometry4 ,n[1 9 t ,my/]y y may f9d
 a sort ( comb9ation ( ,a/ronomy &      
,euclid's ,geometry1 & ?r\gh ?is        
comb9ation a mo/ ?or\gh completion &    
f9i%+ ( !m bo?2 & ?is 0 ! reason :y ,i  

wait$ ) int5se long+ to see :at sort (  
an argum5t ,galileo w\ld produce 9 fav\r
 ( ! ,py?agorean sy/em ( ! univ]se4     
,aft] ?is explanation1 ,galileo's lett] 
ab\t ?is argum5t 0 z foll[s3--      #bf 
,kepl]1 9 8 ,my/]y ( ! ,univ]se1        
endeav\r$ to     connect ! orbits ( !   
planets ) ! five regul> solids1     ?us3
 ,if 9 a sph]e 7i47 a cube be inscrib$1 
& 9 ! cube     a sph]e 7ii472 & 9 t     
sph]e a tetrah$ron1 & 9 !     tetrah$ron
 a sph]e 7iii472 & 9 t sph]e a          
dodecah$ron1     & 9 ! dodecah$ron a    
sph]e 7iv472 & 9 t sph]e an             
icosah$ron1 & 9 ! icosah$ron a sph]e    
7v472 & 9 t     sph]e an octah$ron1 & 9 
! octah$ron a sph]e 7vi471     !        
diamet]s ( ^! six sph]es w be           
proportional to !     diamet]s ( !      
orbits ( ,saturn1 ,jupit]1 ,m>s1 ! ,e>?1
 ,v5us1     & ,m]cury respectively2 or1 
z ,kepl] expresses x1 ! common     c5tre
 ( ^! sph]es repres5ts ! position ( !   
,sun1 & !     six sph]es repres5t !     
sph]es ( ! planets4      ,by ^!         

consid]ations1 h[ev]1 ,kepl] 0 l$ to    
enunciate     8 ?ird law1 t ! squ>es ( !
 p]iodic times ( planets     are        
proportional to ! cubes ( _! mean       
di/ances f !     sun4--,,kepl]1         
,prodromus ,diss]tationum ,ma!matic>um  
cont95s     ,my/]ium ,cosmographicum1   
etc4 7,tb+51 #aeif47      8,illu/rissimo
 e ,rev]5dissimo ,signore mio           
col5dissimo4      8 tempo *e io decif]i 
a ,vo/ra ,signoria ,illu/rissima e      
,rev]5dissima e p] lei al ,sig4 ,kepl]o 
le lett]e traspo/e     le quali alcune  
settimane sono le inviai2  tempo dico1  
giac*     sono int]am5te *i>o della v]it
 del fatto1 sic* non ci     re/a un     
m9imo scrupolo1 o dubbio4 ,sapranno     
dunque come circa a     tre mesi fa     
v$5dosi ,v5]e vesp]t9a la com9ciai ad   
oss]v>     dilig5tem5te coll'oc*iale1 p]
 v$] col s5so /esso     quello di *e non
 dubitava punto l'intelletto4 ,la vidi  
dunque sul     pr9cipio di figura       
rotonda1 pulita e t]m9ata1 ma molto     
picciola2     di tal figura si mant5ne  

s9o *e com9ci ad avvic9>si alla     sua 
massima digressione1 ma tra tanto &     
cresc5do 9 mole4     ,com9ci poi a      
manc>e dalla rotondit nella sua p>te    
ori5tale     ed avv]sa al ,sole1 e 9    
po*i giorni si ridusse ad ess] un mezzo 
c]*io p]fettissimo1 e tale si mant5ne1  
s5za punto alt]>si1     f9* incom9ci    
ritir>si v]so il ,sole1 allontan&osi    
dalla tang5te4 ,ora va cal&o dal mezzo  
c]*io1 e si mo/ra     cornicolata1 e &] 
assottigli&osi s9o all'occultazione1    
riduc5dosi allora con corna             
sottilissime4 ,qu9di pass&o all'        
app>izione mattut9a1 la v$remo pur      
falcata1 e sottilissima e     colle     
corna avv]se al ,sole2 &] poi cresc5do  
f9o alla massima     digressione1 dove  
app>ir semicircol>e1 e tale s5za alt]>si
 si     mant]r molti giorni1 e poi dal  
mezzo c]*io pass] pre/o al     tutto    
tondo1 e cos rotonda si cons]v] poi p]  
molti mesi4 ,il     suo diametro adesso 
circa c9que volte maggiore di quello1 *e
     si mo/rava nella sua prima         

app>izione vesp]t9a2 dalla quale        
mirabile esp]i5za abbiamo s5sata1 e c]ta
 dimo/razione di due     gran que/ioni  
/ate f9 qui dubbie tr i maggiori +egni  
del     ,mondo4 ,l'una 1 *e i ,pianeti  
tutti son di lor natura t5ebrosi        
7accad5do anco a ,m]curio l'i/esso1 *e a
 ,v5]e74 ,l'altra1 *e     ,v5]e         
necess>issimam5te si volge intorno al   
,sole1 come anco     ,m]curio1 cosa1 *e 
degli altri ,pianeti1 fu cr$uta da'     
,pitagorici1     dal ,cop]nico1 dal     
,kepl]o e da' loro seguaci1 ma non      
s5satam5te     provata1 come ora 9      
,v5]e1 ed 9 ,m]curio4      8,av]anno    
dunque il ,sig4 ,kepl]o1 e gli altri    
,cop]nicani da     glori>si di av]      
cr$uto e filos(ato b5e1 sebb5e ci       
toccato1     e ci  p] tocc>e ancora ad  
ess] reputati dall' univ]sit dei        
,filos(i 9 libris1 p] poco int5d5ti1 e  
poco m5o *e /olti4      8,le p>ole      
dunque1 *e m&ai traspo/e1 e *e dicevano1
          ,haec immatura a me jam fru/ra
 leguntur1 o4y4      dicono ord9ate     

,cyn?iae figuras aemulatur mat] amorum4 
8,cio1 *e ,v5]e imita le figure della   
,luna4 ,oss]vai tre notti     sono      
l'ecclisse1 nella quale non vi  cosa    
notabile1 solo si v$e     il taglio     
dell'ombra indi/9to1 confuso e come     
annebbiato1     e que/o p] d]iv>e essa  
ombra dalla ,t]ra lontanissima da       
essa ,luna4 ,voleva scriv]e altri       
p>ticol>i1 ma ess5do /ato     tratt5uto 
molto da alcuni g5tiluom9i1 ed ess5do   
l'ora     t>dissima1 son =zato a f9ire4 
,favoriscami salut>e 9 mio nome     i   
,,ss4 ,kepl]o1 ,asdale e ,segheti1 ed a 
,vo/ra ,signoria ,illu/rissima     con  
ogni rev]5za bacio le mani1 e dal       
,signore ,dio gli prego     felicit4 ,di
 ,fir5ze il primo di ,g5naio #afaj4 ,ab 
,inc>natione4      8,di ,vo/ra ,signoria
 ,illu/rissima e ,rev]5dissima ,s]vidore
     obbligatissimo4      ,galileo      
,galilei40  ,su* is ,galileo's lett]2 b 
let me give y ! sub/ance ( x3--      8,x
 is "t = me to disclose ! me?od ( read+ 
! lett]s     :i* "s weeks s9ce ,i s5t y 

z an anagram4 ,x is "t n[1 ,i     mean1 
aft] ,i h become q c]ta9 ab\t ! matt]1 s
 mu*     s t ,i h no long] ev5 a %ad[ ( 
d\bt4 ,y mu/ "k !n     t ab\t ?ree mon?s
 ago1 :5 ! /> ( ,v5us c\ld be se51      
,i began to look at x ?r\gh a telescope 
) great att5tion1     s t ,i might grasp
 ) my physical s5ses an idea :i* ,i 0   
ent]ta9+ z c]ta94 ,at fir/ !n y mu/ "k !
 planet     ,v5us appe>$ ( a p]fectly   
circul> =m1 accurately s1 &     b\nd$ by
 a di/9ct edge1 b v small2 ?is figure   
,v5us kept     until x began to approa* 
its greate/ di/ance f ! sun1     &      
mean:ile ! app>5t size ( its orb kept on
 increas+4     ,f t "t x began to lose  
its r\ndness on ! ea/]n side1     :i* 0 
turn$ away f ! sun1 & 9 a few days x    
contract$     its visible portion into  
an exact semicircle2 t figure la/$      
)\t ! smalle/ alt]ation until x began to
 return t[>ds     ! sun :]e x leaves !  
tang5t drawn to its epicycle4#bg     ,at
 ?is "t x loses ! semicircul> =m m & m1 
&     keeps on dim9i%+ t figure until   

its conjunction1 :5 x     w wane to a v 
?9 cresc5t4 ,aft] complet+ its passage  
pa/ ! sun1 x w appe> to u1 at its       
appe>ance z a morn+     />1 z only      
sickle-%ap$1 turn+ a v ?9 cresc5t away f
     ! sun2 aft]w>ds ! cresc5t w fill up
 m & m until     ! planet rea*es its    
greate/ di/ance f ! sun1 9 :i*          
position x w appe> semicircul>1 & t     
figure w la/     = _m days )\t          
appreciable v>iation4 ,!n by degrees1 f 
be+ semicircul> x w *ange to a full orb1
 & w keep t     p]fectly circul> figure 
= sev]al mon?s2 b at ?is in/ant     !   
diamet] ( ! orb ( ,v5us is ab\t five    
times z l>ge z     t :i* x %[$ at its   
fir/ appe>ance z an ev5+ />4       8,f !
 obs]vation ( ^! wond]ful ph5om5a we are
 suppli$     ) a det]m9ation mo/        
conclusive1 & appeal+ to ! evid5ce     (
 our s5ses1 ( two v important problems1 
:i* up to ?is     day 7 discuss$ by !   
greate/ intellects ) diff]5t            
conclusions4 ,"o is t ! planets are     
bodies n self-lum9\s     7if we may     

ent]ta9 ! same views ab\t ,m]cury z we d
 ab\t     ,v5us74 ,! second is t we are 
absolutely compell$ to say     t ,v5us  
7& ,m]cury also7 revolves r\nd ! sun1 z 
d also     all ! re/ ( ! planets4 ,a    
tru? believ$ inde$ by !     ,py?agorean 
s*ool1 by ,cop]nicus1 & by ,kepl]1 b    
nev] prov$     by ! evid5ce ( our s5ses1
 z x is n[ prov$ 9 ! case (     ,v5us & 
,m]cury4 ,kepl] !re=e & ! re/ ( ! s*ool 
( ,cop]nicus h good reason = boa/+ t !y 
h %[n     !mselves good philosoph]s1 & t
 _! belief 0 n devoid     ( f\ndation2  
h[ev] mu* x has be5 _! lot1 & may ev5   
h]eaft] be _! lot1 to be reg>d$ by !    
philosoph]s ( our     times1 :o         
philosophise on pap]1 ) an univ]sal     
agreem5t1 z     m5 ( no intellect1 &    
little bett] ?an absolute fools4        
8,! words :i* ,i s5t ) _! lett]s        
transpos$1 & :i*     said1        ,haec 
immatura a me jam fru/ra leguntur1 o4y4 
:5 r$uc$ to _! prop] ord]1 read ?us1    
,cyn?iae figuras aemulatur mat] amorum3 
,! "m ( ! ,loves rivals ! phases (      

,cyn?ia3      t is1        ,v5us        
imitates ! phases ( ! ,moon4      8,?ree
 days ago ,i obs]v$ an eclipse ( ! moon1
 b n any?+     wor?y ( special notice   
occurr$ 9 x4 ,only ! edge ( !     %ad[  
appe>$ indi/9ct1 blurr$1 & hazy2 ! cause
 ( !     ph5om5on no d\bt is t ! %ad[   
has its orig9 at ! e>?1     at a great  
di/ance f ! body ( ! moon4      8,i h "s
 o!r p>ticul>s1 b ,i am prev5t$ by "t f 
writ+ ab\t !m1 etc40  ,s writes         
,galileo4      #bg ,9 ! ,ptolemaic sy/em
 ! e>?'s c5tre 0 reg>d$ z !     c5tre ( 
! univ]se1 & ! movem5ts ( ! heav5ly     
bodies     7 expla9$ by ecc5trics &     
epicycles4 ,! sun 0 conceiv$     to     
describe a circle ab\t a po9t n exactly 
co9cid+ ) !     c5tre ( ! e>?1 call$ !  
sun's ecc5tric4 ,! planets     describ$ 
epicycles 7circles7 ^: c5tres describ$  
ecc5trics     7circles71 & ! c5tres ( ^!
 ecc5trics co9cid$ ) !     c5tre ( !    
sun's ecc5tric4 ,9 ! case ( ,m]cury &   
,v5us     ! c5tre ( ! epicycle 0 always 
on ! l9e drawn f !     c5tre ( !        

ecc5tric to ! sun's c5tre4 ,9 ! case ( !
     o!r planets ! con/ruction 0 m      
complicat$4 ,! /ation>y     po9ts 7     
det]m9$ by draw+ tang5ts f ! e>?'s c5tre
     7or ! obs]v]7 to ! epicycle1 z 9 ! 
figure 7#a74--7;,,gass5di1              
,in/itutio ,a/ronomica1 #afdg47 ,?is w  
expla9 ,kepl]'s     description ( !     
/ation>y po9ts z ! po9ts :]e !          
planet leaves ! tang5t to its epicycle1 
suppos+ t he uses     ! t]ms ( ! curr5t 
7i4e4 ,ptolemaic7 a/ronomy4 ,cop]nicus  
plac$ ! sun in/ead ( ! e>? at ! c5tre ( 
! univ]se1     b to det]m9e ! positions 
( ! planets at any giv5 "t     ) z mu*  
accuracy z 0 atta9able ) ! ,ptolemaic   
sy/em1     he 0 oblig$ to use a simil>  
me?od ( ecc5trics & epicycles1     s t  
,kepl]'s expression may be und]/ood to  
describe !     /ation>y po9ts accord+ to
 ! ,cop]nican !ory1 ?\gh x     is /ill  
/range t he %\ld n recognise !          
elliptical =m     ( ! planet>y orbits1  
:i* he _h lately demon/rat$ aft]     mo/
 labori\s reason+ 9 8 ,comm5t>ies on !  

,motion ( !     ,planet ,m>s1 #afji4    
,galileo's own expression seems to      
describe !     /ation>y po9ts accord+ to
 ! ,cop]nican sy/em1 z w\ld be          
expect$1 z ! po9ts :]e ! planet leaves !
 tang5t drawn     to its orbit f ! e>?  
7,fig4 #b74  ,:at n[1 de> read]1 %all we
 make out ( our telescope8 ,%all we make
 a ,m]cury's magic-w& to cross ! liquid 
e!r )1 &1 l ,lucian1#bh lead a colony to
 ! un9habit$ ev5+ />1 allur$ by !       
sweetness ( ! place8 or %all we make x a
 ,cupid's arr[1 :i*1 ent]+ by our eyes1 
has pi]c$ our inmo/ m9d1 & fir$ u ) a   
love ( ,v5us8 ,= :at language is too    
/rong = ! m>vell\s beauty ( ?is orb1 if1
 hav+ no light ( its own1 x c atta9     
simply by ! borr[$ light ( ! sun to su* 
spl5d\r1 z ,jupit] has n1 nor ! moon1   
?\gh enjoy+ a proximity to ! sun z close
 z ,v5us2 = if ! moon's light be comp>$ 
) ! light ( ,v5us1 x w be se5 to be     
c]ta9ly great] on acc\nt ( ! app>5t     
magnitude ( ! moon1 b1 9 comp>ison ) !  
light ( ,v5us1 dull1 dead1 & lead54 ,o  

truly gold5 ,v5us6 ,w any "o d\bt any m 
t ! :ole orb ( ,v5us is wr\ght mo/      
smoo?ly out ( pure unalloy$ gold1 s9ce  
its surface1 :5 only plac$ 9 ! sunlight1
 reflects a spl5d\r s int5se6 ,& "h let 
me add my exp]im5ts ab\t ! alt]ation ( !
 light ( ,v5us on bl9k+ ! eye1 :i* ,i h 
exam9$ 9 ! "p ( my ,a/ronomy :i* treats 
( ,optics4 ,reason+ w be able to        
conclude no?+ else b ?is1 t ! orb (     
,v5us turns on its own axis ) an        
exce$+ly swift rotation1 display+ "o    
aft] ano!r diff]5t p>ts ( its surface   
:i* are m or less capable ( reta9+ !    
sun's light4#bi      #bh ,lucian1 ,v]4  
,hi/4 i4 #ab4      #bi ,! fir/ sci5tific
 det]m9ation ( ! p]iod ( !     rotation 
( ,v5us 0 made by ,dom9ique ,cass9i 9   
#afff1 f     obs]vations ( spots on !   
planet1 & conclud$ to be ab\t #bd       
h\rs2 b 9 #agbf ,bian*9i d$uc$ a p]iod (
 #bd d4 #h h4 f     simil> obs]vations4 
,! true p]iod is consid]$ to be #bc h4  
#ba     m41 det]m9$ by ,s*roet] by a    
s]ies ( obs]vations la/+     f #aghh to 

#agic on ! p]iodicity ( ! de=mation ( ! 
horns ( ,v5us4--7,,arago1 ,a/ronomie    
,populaire1 #ahed47      ,kepl]'s       
/atem5ts c only be reg>d$ z             
anticipations (     ph5om5a n yet       
actually obs]v$4  ,b en\gh ( my own     
conclusions4 ,let u n[ he> z an epilogue
 ,galileo's conclusions built up out (  
all ! obs]vations :i* he has made ) 8   
telescope1 & ann\nc$ f "t to "t4 ,?us he
 writes once m3--  ,sid5ote3 ,galileo's 
conclusions ) reg>d to ! inh]5t nature (
 ! brightness ( ! />s4                  
8,illu/rissimo e ,rev]5dissimo ,signore 
mio col5dissimo4      8,ho ricevuto     
gu/o1 e cont5to p>ticol>issimo nella    
lettura     dell' ultima di ,vo/ra      
,signoria ,illu/rissima e ,rev]5dissima 
delli #g /ante1 ed 9 p>ticol>e 9 quella 
p>te dove ella     m'acc5na la          
favorevole incl9azione dell' ,illu/riss4
 ,sig4     ,cons4 ,wackh]1 v]so di me1  
la quale io inf9itam5te /imo1     ed    
apprezzo2 e poi* quella ha pr9cipalm5te 
orig9e dall'     av] io incontrate      

oss]vazioni necess>iam5te dimo/ranti    
conclusioni p] avanti t5ute v]e da sua  
,signoria ,illu/rissima     p] conf]m>mi
 maggiorm5te il possesso di grazia tanto
 pregiata     da me1 prego ,vo/ra       
,signoria ,illu/rissima e ,rev]5dissima 
a     f>gli int5d]e p] mia p>te come    
con=me alla cr$5za di     ,sua ,signoria
 ,illu/rissima ho dimo/razione c]ta1 *e 
siccome     tutti i ,pianeti ricevono il
 lume dal ,sole1 ess5do p] se /essi     
t5ebrosi1 e opa*i2 cos le ,/elle fisse  
rispl5dono p] lor     natura1 non       
bisognose dell' illu/razione de' raggi  
sol>i1 li     quali1 ,dio sa1 se arriv9o
 a tanta altezza1 pi di quello1 *e      
arrivi a noi il lume di una di esse     
fisse4 ,il pr9cipal fondam5to     del   
mio discorso  nell' oss]v>e io molto    
evid5tem5te con     gli oc*iali *e quei 
,pianeti di mano 9 mano1 *e si trovano  
pi vic9i a noi1 o al ,sole1 ricevono    
maggiore spl5dore1 e pi     illu/rem5te 
ce lo riv]b]ano2 e p]ci ,m>te p]igeo1 e 
a noi     vic9issimo si v$e assai pi    

spl5dido1 *e ,giove2 b5* a     quello di
 mole assai inf]iore2 e difficilm5te se 
gli pu coll'     oc*iale lev>e quella   
irradiazione1 *e imp$isce il v$]e il suo
     disco t]m9ato1 e rotondo2 il *e 9  
,giove non accade1 v$5dosi              
esquisitam5te circol>e4 ,saturno poi p] 
la sua gran lontananza     si v$e       
esattam5te t]m9ato1 s la ,/ella maggiore
 di mezzo1     come le due piccole      
lat]ali2 ed app>e il suo lume languido1 
ed     abbac9ato e s5za niuna           
irradiazione1 *e imp$isca il di/+u]e    
i suoi tre piccoli globi t]m9atissimi4  
,ora poi* ap]tam5te     veggiamo1 *e il 
,sole molto spl5didam5te illu/ra ,m>te  
vic9o1     e *e molto pi languido  il   
lume di ,giove 7sebb5e s5za lo          
/rum5to app>e assai *i>o1 il *e accade  
p] la gr&ezza1 e     c&ore della ,/ella7
 languidissimo1 e fosco quello di       
,saturno1     come molto pi lontano1    
quali dov]iano app>irci le ,/elle       
fisse lontane indicibilm5te pi di       
,saturno1 qu&o il lume loro     d]ivasse

 dal ,sole8 ,c]tam5te debolissime1      
torbide e smorte4 ,ma     tutto         
l'opposito si v$e1 p]oc* se rimir]emo p]
 esempio il     ,cane1 incontr]emo un   
fulgore vivissimo1 *e quasi ci toglie la
     vi/a1 con una vibrazione di raggi  
tanto fi]a1 e poss5te1 *e     9         
comp>azione di quello rimangono i       
,pianeti1 e dico ,giove e     ,v5]e     
/essa1 come un impurissimo vetro        
appresso un limpidissimo     e f9issimo 
diamante4 ,e b5* il disco di esso ,cane 
app>isca non     maggiore della         
c9quantesima p>te di quello di ,giove1  
tuttavia la     sua irradiazione  gr&e1 
e fi]a 9 modo1 *e l'i/esso globo     tra
 i proprii cr9i s'implica1 e quasi si   
p]de1 e con qual*e     difficolt si     
di/+ue2 dove *e ,giove 7e molto pi      
,saturno7     si v$ono e t]m9ati1 e di  
una luce languida1 e p] cos dire        
quieta4 ,e p] tanto io /imo1 *e b5e     
filos(]emo1 ref]5do la     causa della  
sc9tillazione delle ,/elle fisse1 al    
vibr>e1 *e elle     fanno dello spl5dore

 proprio e nativo dall'intima loro      
su/anza2     dove *e nella sup]ficie de'
 ,pianeti t]m9a pi pre/o1 e si          
f9isce l'illum9azione1 *e dal ,sole     
d]iva1 e si p>te4 ,se io     s5tir      
qual*e p>ticol>e que/ione ricevuta dal  
m$esimo ,sig4     ,wackh]1 non re/]     
d'affatic>mivi intorno1 p] dimo/r>mi1   
quale io sono desid]osissimo di s]vire  
un tanto ,signore1 e non     gi con     
isp]anza di aggiung]e al t]m9e          
conseguito dal suo     discorso1 p]*    
b5issimo compr5do1 *e a quanto sia      
passato     p] lo f9issimo cribro del   
giudizio di esso1 e del ,sig4 ,kepl]o1  
non si pu aggiung]e di squisitezza2 n io
 pret5d]ei altro1     *e col dubit>e1 e 
mal filos(>e1 eccit> loro al ritrovam5to
     di nuove sottigliezze4 ,gl'+egni   
s+ol>i1 *e 9 gran num]o     fioriscono  
nell',alemagna1 mi hanno lungo tempo    
t5uto 9 desid]io     di v$]la1 il qual  
desid]io ora si raddoppia p] la nuova   
grazia     dell',illu/rissimo ,sig4     
,wackh]1 la quale mi f>ebbe div5ir      

gr&e ogni picciola occasione1 *e mi si  
pres5tasse4 ,ma ho di     sov]*io       
occupata ,vo/ra ,signoria ,illu/rissima 
e ,rev]5dissima4     ,degnisi p] f9e di 
(f]irmi e d$ic>mi devotissimo s]vidore  
all',illu/rissimo ,sig4 ,wackh]1 salut&o
 anco c>am5te il ,sig4     ,kepl]o1 ed a
 lei con ogni riv]5za bacio le mani1 e  
dal ,signore     ,dio le prego somma    
felicit4      8,di ,fir5ze li #bf di    
,m>zo #afaa4 ,di ,vo/ra ,signoria       
,illu/rissima     e ,rev]5dissima       
obbligatissimo ,s]vidore1      ,,galileo
 ,,galilei40   ,:5 translat$1 ! mean+ is
 z foll[s3--      8,y\r la/ lett] has   
exce$+ly pleas$ me1 especially t "p     
:i* assures me ( ! fri5dly feel+        
ent]ta9$ t[>ds me by     ! mo/ illu/ri\s
 ,imp]ial ,c\nsellor1 ,wagh]1 :i* ,i =  
my     "p highly appreciate4 ,& s9ce !  
cause ( ?is fri5dl9ess     is1 t ,i h   
inconte/ably demon/rat$ by "s           
obs]vations (     m9e c]ta9 conclusions 
:i* he _h long held z true1 ,i wi%      
to confirm my possession ( fav\r1 :i* ,i

 value s mu*1 &     accord+ly ,i ask y  
to give him ?is piece ( news f me2 t    
,i h mo/ conclusive argum5ts ready1 %[+ 
cle>ly t1 j     z he holds1 all !       
planets receive _! light f ! sun1       
be+ by con/itution bodies d>k & devoid (
 light2#cj b t     ! fix$ />s %9e by _! 
own prop] light1 n ne$+ to be           
illum9at$ by ! sun's rays1 s9ce ,god    
kn[s :e!r !y rea*     ! v remote region 
( ! fix$ />s ) int5sity ev5 equal     to
 ! small int5sity ) :i* ! rays ( ! fix$ 
/>s come     d[n to u4      8,my        
demon/ration dep5ds *iefly on ?is fact1 
t ) !     telescope ,i h di/9ctly obs]v$
 t ! planets receive     great]         
brightness1 & reflect x m int5sely1 9   
proportion     z ea* "o is ne>] to u &  
to ! sun4 ,s ,m>s 9 p]igee1     t is1 :5
 ne>e/ to ! e>?1 greatly surpasses      
,jupit] 9     brightness1 al?\gh 9      
actual size x is f> inf]ior to ,jupit]2 
& 9 consequ5ce x is difficult to receive
 ! effulg5ce (     ?is planet 9 !       
telescope1 = x is s great z to prev5t ! 

eye f be+ able to di/+ui% ! circul>     
t]m9ation ( !     planet's disc4 ,?is   
does n happ5 9 ! case ( ,jupit]1 = x    
appe>s q circul>4 ,! next planet1       
,saturn1 on acc\nt ( its     great      
di/ance likewise--= inde$ x is ! mo/    
remote ( !     planets1--appe>s b\nd$ by
 a well-def9$ edge1 bo? ! great]     orb
 9 ! middle & ! two small orbs at its   
sides4 ,inde$1     x appe>s to %9e ) a  
fa9t & delicate light1 )\t any          
effulg5ce to prev5t an obs]v] recognis+ 
! well-def9$     t]m9ation ( its ?ree   
orbs4 ,s9ce1 !n1 we see t ,m>s1 !       
ne>e/ ( ! ?ree1 is illum9$ by ! sun ) v 
great     spl5d\r1 & t ! light (        
,jupit]1 at a great] di/ance1     is mu*
 m fa9t 7al?\gh )\t ! use ( an in/rum5t 
x     appe>s tol]ably bright1 :i* is due
 to ! size & brilliancy     ( its body71
 & t ! light ( ,saturn1 at ! greate/    
di/ance1 is mo/ fa9t1 & almo/ wat]y1 (  
:at k9d1 d y     ?9k1 w\ld appe> ! light
 ( ! fix$ />s1 :i* are at an            
immeasurable di/ance fur!r f ! sun ?an  

,saturn1 if !y     only receiv$ light f 
! sun8 ,mo/ c]ta9ly1 extremely feeble1  
indi/9ct1 & pallid4 ,& yet we f9d q !   
contr>y2 =1     let u look ) our eyes at
 ! ,dog-,/>1 = example4 ,we %all        
enc\nt] a mo/ vivid brilliancy1 :i*     
almo/ pricks ! eye     ) ! rapid sp>kl+ 
( its rays1 ( su* int5sity t1 9         
comp>ison ) x1 ! planets1 ev5 ,jupit]1 &
 ,v5us too1 are     z ?or\ghly out%one z
 common & bad glass comp>$ ) a          
highly poli%$ & mo/ sp>kl+ diamond4 ,&  
al?\gh ! orb (     ! ,dog-,/> appe>s no 
l>g] ?an ! fiftie? "p ( ,jupit]'s       
disc1 nev]!less its brilliancy is great 
& v /rong2 s t     ! =m ( its disc1 :i* 
y expect to see1 hides itself among     
! rays ( its own refulg5ce1 envelops    
itself 9 !m1 & almo/     disappe>s2 & x 
is n di/+ui%$ )\t "s difficulty     f ! 
rays :i* surr\nd x4 ,:]eas ,jupit]1 &   
/ill     m ,saturn1 are se5 well def9$2 
& _! light is )\t     int5sity1 &1 if ,i
 may say s1 quiesc5t4 ,:]e=e ,i ?9k t   
we %all rightly apply our philosophy if 

we ref] ! cause ( !     tw9kl+ ( ! fix$ 
/>s to vibrations ( a brilliancy1 :i*   
is _! own1 belong+ to _! con/itution1 & 
inh]5t 9     _! sub/ance1 & say1 on !   
o!r h&1 t ! illum9ation     ( ! planets1
 :i* is d]iv$ f ! sun1 & di/ribut$ to   
! _w1 is limit$ to _! surface40  ,^! are
 ! sci5tific conclusions 9 ,galileo's   
lett]2 ! re/ ,i omit4      #cj ,proctor 
7,o!r ,worlds ?an ,ours1 #ahge7 has giv5
 "s     reasons = believ+ t ,jupit] &   
,saturn %9e 9 "p )     _! own light1 ow+
 to _! great int]nal heat4  ,y see !n1  
/udi\s read]1 h[ ! subtle m9d (         
,galileo1 9 my op9ion ! fir/ philosoph] 
( ! day1 uses ?is telescope ( ours l a  
sort ( ladd]1 scales ! fur!/ & l(tie/   
walls ( ! visible _w1 surveys all ?+s ) 
8 own eyes1 &1 f ! position he has ga9$1
 d>ts ! glances ( 8 mo/ acute intellect 
^u ^! petty abodes ( ours--! planet>y   
sph]es ,i mean1--& comp>es ) ke5e/      
reason+ ! di/ant ) ! ne>1 ! l(ty ) !    
deep4       ,,vale ,,et ,,deum ,,9      
,,op]ibus ,,suis ,,celebr>e ,,nunquam   

,,des9e4      ,,kepl]1 ,n>ratio4        
,ed9burgh ,univ]sity ,press3  ,,?omas   
,,& ,,ar*ibald ,,con/able1 ,,pr9t]s ,,to
 ,,h] ,,maje/y4