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

M₂ + E₂ = S I where M₂ = Mandasphuta-
graha and E₂ = the Sīghraphala where from we have
δM₂ + δE₂ = δS II i.e. Mandasphutagati + Sīghragati
phala = Spastagati (a) Let E₂ be maximum so that
δE₂ = 0, then δM₂ = δS. This means that in the helio-
centric figures 11 and 12, at the points a and b,: the
Sīghraphala being maximum, the Mandasphuta gati will be
itself the Spashtagati. This line ab, it will be seen corres-
ponds with the so called “कक्षामध्यगततिर्यग्रेखा (प्रतिवृत्तसम्पातरेखा)”
i.e. the line cutting the eccentric, drawn through the centre
of the deferent.
(b) The planet begins to retrograde only after the
Spashtagati vanishes i.e. after δM₂ + δE₂ becomes Zero.
Taking δM₂ to be almost a constant since the Mand