ब्राह्मस्फुटसिद्धान्त (ब्रह्मगुप्त - शून्य, कुट्टक, बीजगणित एवं सम्पूर्ण २१ अध्याय सान्वय सटीक)

UTTARAKHAṆḌA KHĀDYAKA 97 Here also Brahmagupta is more accurate. Again, the length of the sidereal period of the Moon's apogee = 1577918450000 / 488105858 days = 3232.732048 days. Āryabhaṭa's value of the same is 3231.987844 days, and the modern value is 3232.3754 days. Hence Brahmagupta's result is by 0.3566 of a day out, while Āryabhaṭa's is by 0.3876 of a day in. Further in the Uttara-Khaṇḍakhādyaka(IX.10) we have : Deduct 354½ from the ahargaṇa, divide the remainder by 6792 ; subtract the quotient that is obtained in revolutions etc. from the circle : the result is the longitude of the ascending node.¹ (IX.10) Here Brahmagupta gives the approximate period of the sidereal revolution of the Moon's node to be=6792 days. This according to his Brāhmasphuṭasiddhānta = 1577916450000 / 232311168 days = 6792.25396 days, which according to Lockyer would be 6793.39108 days and according to the Khaṇḍakhā