BOOK OF MATHEMATICAL PROBLEMS. 



1626. The maximum value of the aberration in declination of 

 a given star is 



20-5" Jl - (cos 8 cos <u -f sin 8 sin <o sin a) a ; 



a, 8 being the right ascension and declination of the star, and co 

 the obliquity of the ecliptic. 



1 ''.J7. If a, a'; 8, 8' be the right ascensions and declinations 

 of t\vo stars whose aberrations in declination vanish simultane- 

 ously, and A the sun's right ascension at the time of their vanish- 

 ing; 



tan 8 sin a tan 8 / sin a' 



tan 8 cos a tan 8' cos a " 



1628. If the latitude of a place has been determined by 

 observation of two zenith distances of the Sun and the time 

 between them, and each observed distance was too great by the 

 same small quantity hj the consequent error in the latitude 

 will be 



cos 

 a, a' being the azimuths at the times of observation. 



THE END. 



CAMBRIDGE: PRINTED AT THE UNIVERSITY PRESS. 



