1919.] Ancient Hindu Spherical Astronomy. 157 
point of Aries.’ The sun moves along the ecliptic in the direc- 
tion YdL. The circle PXP’ is a declination circle (krantivritia) 
through the star X, and KXXK’ is a circle of latitude (vikshepa). 
In some Hindu texts Ya instead of Yd is termed the longi- 
tude of X, and Xa instead of Xd is termed the latitude. These 
are sometimes called the ‘polar’ or ‘false’ longitude and 
Fig. 3. 
latitude. The obliquity » = LYR is only indicated as the 
maximum declination of the sun, or LR, and is generally 
assumed to be 24 degrees. Denoting the true longitude Td by 
\ and the false longitude Ya by 4’, and similarly the true (dz) 
and false (ax) latitudes by B and f’, and the angle Tab by 4, 
and noting that the angle of afb =, and Yba = 90° and 
also Tdc = 90°, we obtain from the spherical triangles Tab 
and xda 
(i) tan A =cot w/ cos’, (ii) sin A = sin B/sin f’, 
(iii) sin A —\’= tan 8/tan A. 
