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

450
Fig. 103 Fig. 104
In the case of Mercury this ratio is 4/10 and that in
the case of Venus is 7/10. Hence the values (420 × 4)/10 and
(204 × 7)/10 ie. 168′ and 142′ roughly accord with the Hindu
values. In other words the Hindu values are geocentric
and the modern heliocentric.
Bhāskara adds that the nodes of Mercury and Venus
as computed previously are to be increased by the Śīghra
anomaly to obtain the actual longitude of the node from
which the latitude is to be computed. This directive is
a beautiful example to show implied heliocentric motion.
Let the convex angle ASN be the heliocentric longitude
of the node measured negatively as the node has a negative
motion along the ecliptic. Adding the heliocentric Śīghra
anomaly to this longitude of the node means convex
angle ASN + ÛSP = 360° + N̂SP − ÂSU = N̂SP − ÂSU. Now
add the longitude of the planet ie. here ÂSU (= ÂES) to
obtain the argument from which the latitude of P the
planet is to be computed. The result is N̂SP as should be.