Jyotihshastra: Astral and Mathematical Literature c4.s5.30

c4.s5.30

Another pupil of Parameśvara’s son, Dāmodara, was the famous author of the Malayālam Yuktibhāṣā, Jyeṣṭhadeva;²⁶³ and among his pupils was Acyuta Piṣāraṭi of Kuṇḍapura in Kerala, the author of the Malayālam commentary on Mādhava’s Veṇvāroha whom we have previously mentioned. Acyuta, who died on 7 July 1621 at the age of about seventy, was a prolific author on astronomy. On planetary theory, eclipses, and the pātas of the Sun and the Moon he wrote before 1596 a Karaṇottama with a vivaraṇa.²⁶⁴ His Sphaṭanirṇayatantra²⁶⁵ deals not only with the computation of the positions of the planets, but also with the constellations and with the celestial and terrestrial spheres; on this also Acyuta wrote his own commentary. On eclipses he composed in 1593 an Uparāgakriyākrama (a work of the same title was written by a contemporary Kerala astronomer, Nārāyaṇa,²⁶⁶) and an Uparāgaviṃśati,²⁶⁷ and on the Moon’s shadow a Chāyāṣṭaka,²⁶⁸ which attempts to compress the material expressed by Nīlakaṇṭha in thirty-two verses in the Candracchāyāgaṇita into the compass of a poem of a quarter of that length. But Acyuta’s most unusual work is the Rāśigolasphuṭānīti²⁶⁹ in which he expounds a method for reducing the Moon’s longitude in its orbit to an ecliptic longitude in accordance with an Islamic tradition initiated by Yaḥyā ibn Abī Manṣūr in the 820’s.²⁷⁰