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

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followed by the ancient Hindu Astronomers to estimate
the distance of the Moon, the spherical radius the hori-
zontal parallax, the orbital radius pertaining to the Moon
could all be deduced and the magnitudes so deduced accord
with their average values in modern astronomy. The
magnitudes pertaining to the Sun however, should be
deemed as parameters.
Verse 6. e - [(S - E) Kₘ / Ks] = 2 α where e = Earth's
diameter, s = The Sun's diameter; Km = Moon's dis-
tance from the Earth's centre; Ks = The Sun's distance
from the Earth's centre, and α = radius of the Earth's
shadow cone at the lunar orbit.
Comm. In fig. 66, let CD be the radius of the Earth's
shadow cone at the lunar orbit. Required to find the
magnitude of CD. Triangles DEF and ESG are similar
Fig. 66
Fig. 67
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