296 



CATALOGUE OF POLAR STARS. 



It is evident that the interval of twenty-four yeans is in this case too great to 

 allow an e.xact reproduction of the intermediate values of T^ — Y^o. We employ, 

 therefore, equations (66) with the interval w = 20, in which it is necessary to compute 

 the additional values for t = 20, < = 60, and f=100. 



DATA FOR THE COMPUTATION OF THE COEFFICIENTS. 



Epoch. 



lo — 'la 



Whence by equations (66) 



d' a 



dt 



1 d'^a 



2 di" 

 1 d'^n 

 6 df 



r= -0.005808 

 = +0.00064775 

 = -0.000026536 



1 di" 



= +0.00000050287 

 = -0.0000000048880 

 = +0.000000000014714 



The values of Fj, — Y^o are now represented as follows : 



