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

445 for Koti are √(R+r - g²- β²) / (u - v) and (T - I) (u - v). When I is given we have to use the latter formula and take T" in the place of T where T, T' and T" are respectively the Sthityardhas (1) Mean, (2) Mean rectified for parallax in latitude and (3) Mean rectified for parallax in longitude. Of course here to arrive at T", method of successive approximation is to be used as β goes on changing from time to time and there is an inter-play between the simultaneous effects of parallax in longitude and that in latitude. On the other hand when g is given we have to use the former formula for the Koti and the Koti thus obtained is to be rectified for the variation in β. So Sūryasiddhānta proposes the formula √(R+r - g)² - β² / (u - v) × T' / T" meaning thereby that the correction for the variation in β is more important because the formula is in terms of β and not the other formula. This formulation is approximate but adopted for the sake of ease. Otherwise from the grāsa, I is to be obtained and the other formula could be used which method is more laborious. Bhāskara's Correction of Brahmagupta's Statement Verses 1, 2 & 3. The statement of Brahmagupta namely that the arc of the Moon's Dṛk-kṣepa will be obtained by the sum or difference of that of the Sun with the latitude of the Vitribha, I (Bhāskara) do not accept. I shall give the reason why. In a place where the latitude is 24°, when the longitudes of the Sun, the Moon and the Node are all 180°, at the time of Sun-rise, the ecliptic occupies the position of the prime-vertical. The Moon will not leave the ecliptic even though depressed by parallax in longitude. Thus there is no parallax in