सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

395
of one lipta in addition to 2½, what should the increase be
for an arbitrary H cos z '? The result is
(H cos z / R) × 1 = cos z.
Note 2. As finding cos z at the time of an eclipse
implies additional arithmetical calculation, and as we have
already with us the data of (1) the time elapsed after rise
of the celestial body (Moon or Sun) till the moment of
the eclipse and (2) half the duration of the day of the body
ie. the rising hour-angle converted into time at the rate
of 6° per nadi, so a rough formula is given using h in the
place of z. The rule of three now used, is 'If for an unnata
equal to the dinārdha or rising hour-angle converted into
nadis, we have an increase of 1 lipta per angula (over and
above 2½ liptas) what shall we have for an arbitrary un-
nata ?' The result added to 2½ liptas, gives the formula
one angula = 2½ + Unnata / Dinārdha . Dinārdha corresponds to
H, the rising hour-angle and Unnata corresponds to (H-h)
where h is the hour-angle at the time.
Bhāskara uses the word 'Angula-liptas' meaning
thereby the liptas that are to be taken to be equal to one
angula while drawing the parilekha of the disc at the time
of its eclipse.
Verse 25. Converting Valana etc. into Angulas.
The measures of the Valana (defined above) or the
Sara ie. the celestial latitude of the Moon or the Rāhu
Bimba or the Bhuja (defined) are to be converted into
Angulas at the rate given by the above formula. While
drawing a figure of the solar eclipse, the celestial latitude
of the Moon is to be drawn in its own direction whereas in
a lunar eclipse, it has to be drawn in the opposite direction.
Comm. The first part is clear. Regarding the second
statement, in as much as the centre of the Rāhu Bimba lies