of the Butherfurd Photographs. 



245 



Star 

 x : (Table V), 



Right Ascensions. 

 4 5 15 40 r 44 



-30.6580 —21.5809 o +25.9804 +34.4505 



X sec d = 52.87 sec 6 ■ x, — 1727.31 — 1215.89 



Jfx • X sec 6 : (Tab. VII), — 0.85 — .60 



iVx • Y: (See below), — 0.14 + .12 



Aa — Xsec S : (Tab. VI), + 5.75 — 3.33 



— Aa : (Page 237), +1723.40 +1219.75 



n x sec 6 : + o 85 + 0.05 



n x : + 0.80 + 0.05 



+1463.77 +1940.98 



+ 0.72 + 0.95 



' — 0.14 + 0.1 1 



— 4.84 + 4.79 



—1459.48 —1948.19 



+ 0.03 

 + 0.03 



1.36 



1.28 





Declinations. 





Star. 4 



5 



15 4o 



44 



y : (Table V), —35.0520 



+28.9675 



—34-9 2 4o 



+ 26.3259 



Y= 52.87 y: — i853'.2o 



+ I53l'5l 



— 184M3 



+I39T.85 



N~ y Y : (Table VII), — 0.75 



+ 0.62 



— 0.75 



+ 0.56 



N x -X sec r? : (See above), — 0.40 



— 0.28 



+ 0.34 



+ 0.46 



AS — Y: (Table VI), — 2.23 



— 1.22 



— 1.59 



— 3-C5 



— A 6 : (Page 237), +1856.81 



—I53I-I7 



+1849.40 



—1390-15 



% : +0.23 



— 0.54 



+ 0.97 



— 0.33 



[X •»/]=— 3650 [F-m a 



,] = — 3240 



[n x ] = — o^o 





[X-%]=+ 980 [r-n, 



/]= — 35IO 



[«*"]= + o*- 33 





j> = + 0.000352 



d=C 



.000030 





r = + 0.00021 1 



±0 



1. 000030 





Jfc = + o."o8 



±o/'o6l 





C = + o/'oi 



±o/ / o6i 





Having found the constants, we may now proceed to get the 

 right ascension and declination of each star on the plate. For 

 this purpose w6 compute the coefficients : 



For Right Ascensions. 

 52.87(1+^+!/*) secrf = 



N x -\-r sec S 

 a n -\- k sec cL 



For Declinations. 

 56.3887 52.87 ( I +p + X,) = 52.9100 



+0.000299 My — r cos S = +0.000035 

 i28°o7 / 54 // .84 S + e = 20°i3 / oi // .39 



A slight change has been made in the two coefficients in the 

 first line, our formulas requiring (i+p+MJ and (i+_p + 3T). 

 This change, however, merely amounts to combining two multi- 

 plications into one; thus, instead of first computing X sec <\ and 

 then multiplying this by (i+j> + Jf), we may apply the factor 

 52.87(1 + p +-^ x ) sec <J to x directly. The formulas require that we 



