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

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nomers came to know that the solstices are preceding by
observations made with the gnomonic shadow at mid-day
around the solstitial days. The day on which the maxi-
mum mid-day shadow is cast by the gnomon is the Winter
solstitial day whereas the day on which the mid-day
gnomonic shadow is maximum in the southern direction
(assuming the place to be of northern latitude and ϕ < ω)
or minimum in the northern direction (ϕ > ω) is the
summer solstitial day. Calculating the Sun's longitude
on that day at noon, we know how far the solstitial points
have preceded behind the points of the Hindu Zodiac which
have Hindu longitudes 90° and 270°. The word अयनांशाः
has therefore the meaning अयनविलोमगत्यंशाः where the
Samāsa may be viewed as a मध्यमपदलोपी समासः
Verses 47, 48. Calculating the five fundamental
H sines of a point of the Zodiac pertaining to a point of
the ecliptic.
The declination has to be computed from the sum of
the Hindu longitude of that point and the Ayanamsas.
Similarly if it be required to find the time before or after
the rise of a point of the ecliptic, we have to compute them
from the sum of the longitude of that point and the
Ayanamsas.
H sin 24° × H sin λ
─────────────────── = H sin δ I
R
√(R² — H sin² δ) = H cos δ = Dyujyā II
δ = H sin⁻¹ (H sin δ) III
s
── × H sin δ = Kujyā IV
12
Kujyā × R
───────── = Charajyā V
H cos δ
H sin⁻¹ (Charajyā) = Charam VI
Comm. (1) Let rA☉ be the ecliptic where r =
Vernal Equinox, A = first point of the Hindu Zodiac,