ON THE SQUARE BAK MICROMETER. 



177 



Correction for Position Zero, Equations (32) and (26). 



flog(-0M8) 

 15 cos 8 



Equation (32) < 



. p' sin 1" 



■ log (38.97) 



Equation (26) 



-0.18 



n 9.2553 

 1.1721 



n 0.4274 

 2.9465 



n 7.4809 

 1.5907 



7t 9.0716 

 Corr.of(a'-a) -0M2 



applied on p. 176. 



From Chauvenet's Astronomy, II., equation (348), C = 50° 12', y = — 3' 32'. 

 Then 



6.443 log sin q 



0.079 log cos (^ 



lOgK 



log tan ^ 

 log tan- ^ 

 log cos 8 

 log tan 8 



0.158 



9.996 



n 9.131 



log sin 2 q 

 log cos 2 q 



n 8.790 

 9.999 



n 9.090 

 9.997 



Refraction Correction. 



In Right Ascension, Equation (23). In Declination, Equation (20). 



tan'' ^ sin 2 g' 

 a. 0. (15 COS 8) 



« 9.248 

 8.905 



8.828 



tan'=^cos2? +1.43 0.155 

 K{d<-d) 8.905 



A(a'-<z) -O'.OOl w 6.981 A (8'- 8) + 0".ll 9.060 



It can be seen by inspection that, on account of small cleclination and 

 moderate motion, the corrections for curvature and proper motions must be in- 

 significant ; also, that the refraction correction must be very small ; the latter 

 is computed, however, to illustrate the special formula (23) for the case of 

 adjustment to apparent motion. 



Value of Diagonal, Equations (33) and (35). 



<.-«o. 



Sam. 



2.07544 

 0.87112 



2.94656 



