Jyotihshastra: Astral and Mathematical Literature c4.s5.25

c4.s5.25

Mādhava’s most distinguished pupil was that Parameśvara of Aśvatthagrāma in Kerala whom we have already encountered as a commentator on Āryabhaṭa’s A; on Bhāskara’s MB and LB (the latter in 1408); on the SS in 1432; on Govindasvāmin’s Mahābhāskariyabhāṣya in 1432; and on Muñjāla’s LM in 1409. He made a series of observations of eclipses of the Sun and the Moon between 1393 and 1432.²⁵¹ These should have influenced his Grahaṇamaṇḍana,²⁵² whose epoch is 15 July 1411; his Grahaṇanyāyadīpikā;²⁵³ and his Grahaṇaṣṭaka.²⁵⁴ Such an influence, however, is not clearly discernible. Parameśvara’s main importance in planetary astronomy in south India was through his dṛggaṇita system, expounded in the Dṛggaṇita²⁵⁵ of 1431. In this the mean motions (with slight modifications in the cases of the lunar mandocca and node) were taken from the Saurapakṣa, though the mean planets were assumed not all to be at Aries 0° at the beginning of the Kaliyuga; the longitudes of the mandoccas (except for Saturn’s) are derived from Muñjāla’s LM; and the dimensions of the manda and śīghra epicycles are new. Parameśvara also wrote two Goladīpikās in which he discusses general astronomical and geographical theories; the first²⁵⁶ of these was written in 1443 and is accompanied by a commentary composed by the author himself, the second²⁵⁷ was composed toward the end of his life, probably in the 1450’s.