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

172 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,