1919.] Ancient Hindu Spherical Astronomy. 18] 
The Pauliéa Siddhanta gives rule (iv) in the form 
t= 2.5 fe — /4(5 — An)(10 — (5 — ad)). 
Since B y 240’ = sin 4 A/sin 90°, 
where 240’ is the moon’s greatest es and 4A is the differ- 
ence in longitude between the moon and its node; and since 
sin AA/sin 10° = 4a / 10, 
nearly, where 10° is the limit from the node for a total eclipse ; 
ave 
B = 240’ x 21 x an/10 x 120 =214n/5, 
where 21’ is the sine of 10 degrees and 120’ is the sine of 90 
degrees Soe to the Paulisa Siddhanta tables (see table 8). 
ow have 
=: s (2taay 221 se me ee 
‘ss 21 ([S)=-2 v6 aN(0—(5 — 4d). 
These rules appear to ignore the variation in latitude that 
takes place, but the Sirya Siddhanta directs us to find the 
value of the moon’s latitude at first contact from the value of 
t, to substitute this value and repeat the process till ¢ is con- 
stant: that is, as we know the longitude of the moon at the 
time of first contact, we calculate the latitude and substitute 
the value so obtained and repeat the process until the results 
no longer 
Solar eclipses.—Apart from the preliminary calcula- 
tions involving parallax very little is given about solar eclipses. 
The Paulisa Siddhainta gives the time of duration as 
t= 3 v/ 64—-— ar 
eae appears to be obtained from the usual rule 
= SAE, + R,)? — Bar; for Ba=5 An approximately, and 
t + R,, = 36’, and v = 720/60 is the oe between the 
mean motions of the moon and sun in a ika 
26. The projection of ec _ - “Since, without a pro- 
— (chedyaka), the precise difference between two eclipses 
not understood, I shall proceed to explain the exalted 
pd a of the projection,”’ writes the alee of the Sitrya 
Siddhanta 
rates - the sun’s motion in longitude, by making a = Re + Ry» and solv- 
for 
~~ vebualne (iii) and Be). neglect bt but the Surya Siddhanta rule is an 
attempt to account for 
* For the Greek scouinncsit of this topic see the Almagest, VI, xi-xiii. 
