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

209 corrections namely Bhujāntara, Chara and the Udayāntara as well. Comm. The correction of chara arises out of the difference between the equatorial risings and local risings of the mean Sun. The local mean Sun pertaing again to uniform motion along the celestial equator Udayāntara has to be effected for l—a, ie. for the local mean Sun on the ecliptic. Thus we have obtained the planetary posi- tions for the local mean Sun-rise and to obtain them for the True Sun-rise, Bhujāntara is to be effected. Verse 65. An alternative method of effecting the Udayāntara correction. Double the H sine of the Sāyana longitude of the Sun derived out of the smaller H sin-table, being multiplied by the daily motion of the planet and divided by 270 and the result in seconds of arc is to be corrected in the plane- tary position positive or negative according as the Sun is in the even or odd quadrants. Comm. (1) In symbols the correction indicated is (m H sin 2l) / 270 where m is the planet's mean daily motion in minutes of arc, l the longitude of the mean Sun, and H sine is taken where the radius = 120. In the commen- tary under the verse, Bhāskara adds 'Each quadrant of the eclipse rises (at the equator) in ¼th of a day but each Rāśi does not rise in 1/12 of a day. Since this Udayāntara correction vanishes when the Sun is at the ends of quadrants it must be construed that this correction increases positively or negatively from the beginning of the quadrant to the middle and decreases from the middle to the end of a quadrant. Saying that a particular Rāśi rises at the equator in n nādikās is only an approximate statement since the Rāśi does not rise uniformly. That is why astronomers like Aryabhata 27