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

263 Iṣṭa Śaṅku / Iṣṭa Hṛti = cos φ = constant = Dinārdha Śaṅku / Hṛti = Sama-Śaṅku / Taddhṛti = Unmaṇḍala Śaṅku / Kujyā (d) (23) Again by virtue of the proportionality of Iṣṭa Hṛti / Iṣṭāntyā = Hṛti / Antyā = Kujyā / Charajyā (e) (24) We have Ishta-Śaṅku / Ishtāntyā = Dinārdha Śaṅku / Antyā = Unmaṇḍala Śaṅku / Charajyā ∴ Iṣṭa Karṇa × Iṣṭāntyā = Dinārdha Karṇa × Antyā = Unmaṇḍala Karṇa × Charajyā (f) (25) ∴ Dinārdha Karṇa = (Unmaṇḍala Karṇa × Charajyā) / Antyā as stated in the verse. Verse 43. (Unmaṇḍala Karṇa × Kṣitijyā) / Hṛti = (Sama Vṛtta Karṇa × Taddhṛti) / Hṛti = Dinārdha Karṇa. Comm. From (c) and (d) above Dinārdha Karṇa × Hṛti = Sama Karṇa × Taddhṛti = Unmaṇḍala Karṇa × Kujyā (g). Khitijyā is the same as Kujyā. From this the statement follows : Verse 44. The ancient Achāryas found the gnomonic shadows when the Sun is on the meridian, prime-vertical and the Kona-Vṛtta (ie, Vertical when the northern or southern Hindu azimuths are 45°) by different methods. I consider him to be the very Sun illuminating the lotus- faces of aitronomers, if anybody could give a method to find the shadow in any required direction, which holds good in all cases universally.