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

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when his true motion equals the mean. It will be 32'-
0'' - 9'''.
Note (4) Substituting the values of P, P' and σ in
III ρ = 52'-42'' + 3'-57'' - 16'-16'' = 40'-23'' = Angular
radius of the shadow-cone at the lunar orbit which almost
accords with the modern value 41'-49''.
Note (5) One may wonder as to how, taking wrong
values for s and Ks, such a correct value could be obtained
for P. In equation II, α, Km, e are all near the truth so
that the terms effected are s/K and e/Ks; but both s and
Ks being parameters s/Ks comes off alright, which is the
angular radius of the Sun's disc which could be measured.
The only vitiating term is e/Ks which is the horizontal
parallax of the Sun which was overestimated unwittingly
by a wrong supposition as indicated in the Kakshādhyāya.
However e/Ks comes to be 3'-57'' and this overestimate is
mitigated to some extent that the Earth has an atmos-
phere which boosts the angular radius of the shadow cone
by about 1' and the remainder of the overestimate makes
amends for the smaller value of P taken.
Verse 7. To convert spatial measures into angular
measure. The diameters of the Sun, the Moon, and Rāhu
in Yōjanas multiplied by R = 3438', and divided
respectively by Ks, Km and Km give their angular measures.
Comm. From fig. 69, (s/2) / Ks = sin Ê = Ê expressed
in radians = E' / 3438 ∴ E' = (3438 × s) / (2 Ks) which means that
the angular radius of the Sun is got by multiplying s/2
ie. the spherical radius of the Sun by R = 3438 and divid-
ing by Ks as mentioned. Similar is the case with respect
to the other two.
Note. - The word Kalākaraṇa is used to signify To
convert into angular measure.