पृष्ठम्:आर्यभटीयम्.djvu/39

• NTRODUCTION xxxix t“Subtract 3600 from the Kali year and divide by 5,808. (Neglect the quotient and) divide the remainder by 1452. Treating the remainder as bhuja, multiply it by 2 and divide by 121 ; the result in degrees etc. is to be applied like the bhuja-phala to the longitudes of the planets and the solstitial points. By so doing, they agree with observation.” (See below, p. 94). The motion of the solstices is evidently the precession of the equinoxes. The value thereof, according to the above passage, is 59.5 per annum, where the modern value is 50" approximately. 17. General remarks Generally, Suryadeva's comments are fuller on the astronomical sections of the Aryabhatiya than on the mathematical sections, with a few exceptions, such as the derivation of the Risines (ii. 11-12, pp. 47-51) and the Pulveriser (ii. 31-32, pp. 70-79). On the astronomical Sections, apart from the detailed exposition of the celestial sphere, (Gola-bandha, pp. 118-22) and the explanation of the motion of the planets through epicycles (Graha-bhramana-vasana, pp. 110-16), his exposition of the Drimandala and Drkksepamandala (pp. 142-43), Akşajya and Lambaka (pp. 144-46), Lankodayaprāna (pp. 147-50), Ksitiya and Caraprāņa (pp. 150-52), Svadeśarāśyudaya (pp. 152-54), Istakālaśañiku (pp. 154-56), Prkksepajya (pp. 160-64) and Drggatiya (pp. 164-66) are full and detailed. It is also noteworthy that, in several cases, he speaks of the demonstration of the different items on the armillary sphere : Cf. com. on iv. 36 (p. 168), 40 (p. 172), 41 (p. 175) etc. 7. Laghumanasa-vyakhya 1. The Work Suryadeva”s commentary on the Laghumanasa of Muñjāla is certainly his magnum opus. This work, which he calls by the name Grahajiāna vasanā, is extensive, discursive and highly informative. For the 60 verses of the text, the commentary extends sixty-fold thereof. The work begins with the Verses : T-in 1. The details furnished here are based on an edition of the under preparation by the present writer from mss. available with um and the Mss. Libraries in Madras and Trivandrum.