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

458 ∴ sin ν = (sin ω cos λ) / (cos δ) or H sin ν = (H sin ω × H cos λ) / (H cos δ) II Comparing I and II, ν would be equal to δ′ provided H cos δ = R. This is accepted as an approximation, as δ is generally small. This approximate formula is given by Sūryasiddhānta in the context of Āyana Dṛk-karma in verse 10, ch. 7, where ν is assumed to be equal to δ′ defined above. Verses 4 and 6. The process called Āyana Dṛk-karma. The Āyana Dṛk-karma correction measured in minutes is obtained by multiplying Āyanavalana by the unrectified celestial latitude, and divided by H cos δ and then multiplied by 1800 and divided by the rising time of the Rāśi which is occupied by the planet. Or again it is obtained approximately by the product of the Āyana- valana and the unrectified celestial latitude divided by the Yaṣṭi. This Āyana Dṛk-karma correction is negative if the hemisphere and the latitude have the same direction. On symbols, Āyana Dṛk-karma correction = (Āyanavalana × β × 1800) / (H cos δ × T) or approximately equal to (β × Āyanavalana) / (Yaṣṭi (= H cos ν)) . Comm. Let G be the position of the planet when the foot of the planet’s secondary (called Grahasthāna) to the Ecliptic namely A is rising, where rCA is the Ecliptic. Let rML be the celestial Equator. Let P and K be the poles of the celestial Equator and Ecliptic respectively. The arc AC of the Ecliptic intercepted between A and the declination circle of G expressed in minutes represents the आयनकलोः formulated in the verse. To find the magnitude of AC, the first formula mentioned above envisages finding