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

229 sidereal, we subtract the rising time of SA from the given Sāvana time and the result will be the same, for, — SA = — (S′A — S′S) = S′S — S′A. which means subtracting SA from the time tantamounts to increasing by S′S and subtracting S′A. This increase by S′S is add- ing what have been defined as gati-kalas so that automati- cally the Sāvana units got converted into sidereal units, by taking the position S and subtracting SA instead of taking the position S′ and subtracting S′A. The result is the same. So, it is said ‘तात्कालिकार्कस्य’ in the beginning of the verse 2. In the second case mentioned in verse 4, if the time given, falls short of the Bhogyāsus, then simply (x × 30) / T where x is the time given in asus and T the rising time of the Rāsi in which both the Sun and the lagna are then situated gives the arc in degrees which if added to the longitude of the Sun gives that of the lagna. Here also the position ‘S’ counts. Verses 5 to 6½. To find conversely the time that has elapsed after Sun-rise given the lagna. The Bhogyasus of the Sun and the Bhuktāsus of the Lagna together with the rising times of intermediate Rasis gives the time required. If the Sun and the Lagna both be in the same Rāsi, then the arc in between them, multiplied by T and divide by 30, gives the time required. If, however, the longitude of the Lagna falls short of that of the Sun, ie. if the Sun be below the horizon, (in this case SL > 180°) then finding the time of rising of SL and subtracting from a day, we have the time of the Lagna before Sun-rise.