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

451
Computing the latitude as indicated in the next verse,
by the formula (H sin NSP × β × R) / (R × K) where β is the maximum
latitude cited above in the respective cases, multiplied by
R and divided by K indicates that the linear magnitude
of the latitude will be increased or decreased according as
K is smaller or greater than R.
Fig. 105 Fig. 106
(a) In this context, we are to throw light on some
moot points. Bhāskara says “मन्दस्फुटो ग्रहः स्वशीघ्र प्रतिमण्डले
भ्रमति, तत्र च तस्य पातोऽपि”, which tantamounts to saying
that the node is situated in the heliocentric orbit “स्वशीघ्र-
तिमण्डल”. The Vimandala or the planet's orbit, taking
for example the inner orbit of P in fig. 105, does not
exactly lie in the plane of the ecliptic as shown in that
figure but is in an inclined position cutting the coplanar
inner orbit in N and N', as shown by the ellipse NPN'
where NP = NP'. The argument to calculate the latitude
is NP' and the formula is (H sin NP' / R) × β to give the helio-
centric linear latitude. To obtain its geocentric linear
value, we have to multiply by R / K.