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

290 the fact that in the position ☉, Sūtra is the H sine of (KA — KE) whereas in the position ☉₁ Sūtra is the H sine of EC ie. H sine of (KE — KC) ie. in the former position Sūtra = H sine (Unnata-Chara) and in the lattter Sūtra = H sin (Chara-Unnata). Thus a reversion in subtraction here, effects a reversion of addition of the Iṣṭayaṣṭi. Similar is the case in the other cases cited by Bhāskara. Analytically this happens so because cos h, when h > 90, becomes negative and adding cos h tantamounts to subtracting sin θ where h = 90 + θ. Verse 64. Another point to be observed. Hvers (90 + θ) = R — H cos 90 + θ̅ = R + H sin θ. The Unmandala Sanku is not observable when δ is south in as much as it is below the horizon ; none the less it may be computed for the purposes of effecting proportion. Fig. 57 Hvers (CG) = Hvers (CÔG) = GH Hvers (EG) = Hvers (EÔG) = Hvers (90 + θ) = R + OH' = R + EL = R + H sin ☉ as defined by Bhāskara,