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

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rendered a Kōti and is placed along V ☉, So the quantity
√(H sin² Z☉ - H sin² ZV) which is the Kōti of the △
formed by H sin Z☉ and H sin ZV, corresponds to the
Kōti of Sphuta-lambana ☉D. So we call
√(H sin² Z☉ - H sin² ZV) as Dṛk-nati, in as much as the
Sphutalambana being placed along V☉ in the form of a
Karṇa when V☉ is Dṛk-mandala-nata, continues to be
placed along V☉ in the deflected position also and
becomes a Kōti corresponding to the Kōti of the triangle
formed by H sin Z☉ and H sin ZV ie. corresponding to
the quantity √(H sin² Z☉ - H sin² ZV). The Sphuta-
lambana should be construed as being associated with
Dṛk-mandala-nata which term is now abbreviated to the
term Dṛk-nati.
At A of fig. 92, the Dṛk-nati = √(R² - H sin² ZV)
= H cos ZV = H cos ZV = Vitribha-lagna-Śanku. Hence
the proportion proceeds in accordance with this Dṛk-nati.
Verse 6 (latter half) and first half of verse 7.
Alternative method of obtaining parallax in longitude.
√(((H cos ZV) / (R/4))² - ((H cos Z☉) / (R/4))²)
or √(((H sin Z☉) / (R/4))² - ((H sin ZV) / (R/4))²)
gives the parallax in longitude expressed in nādīs.
Comm. These formulae just constitude another mode
of expressing the parallax in longitude and the equivalence
of the formulae with the formula (4/R) Dṛk-nati is evident.
Latter half of verse 7. Use of the parallax in
longitude.
The time of the ending moment of New Moon ie. the
moment of geocentric conjunction is to be rectified by this