A History of the Kerala School of Hindu Astronomy (in Perspective) c9.s5.3

c9.s5.3

A branch of astronomy in which intense investigations have been made by Kerala astronomers refers to the computation of eclipses. The phenomenon of eclipses seems to have been exploited fully towards verifying calculations, instituting corrections and devising new methodologies. A reference has already been made to Parameśvara of Dṛggaṇita fame who has recorded the details about a large number of eclipses which he had computed, observed and also suggested corrections to correlate the two. Apart from minor tracts, a number of texts on the computation of eclipses have come down. These include three works having the common title Uparāgakriyā-krama, the first by Nārāyaṇa with commentary, the second by Acyuta Piṣāraṭi, with two commentaries, and a third, which is anonymous; an Uparāgaviṃśati with commentary; Grahaṇamaṇḍana by Parameśvara; six anonymous works with the common title Grahaṇa-gaṇita; four works under the title Grahaṇaṣṭaka, one of which is by Parameśvara and the others anonymous; and the three works, Candra-graha-gaṇita, Candra-sūryoparāga-gaṇita and Sūrya-grahaṇa-gaṇita, all anonymous. Two works on eclipses which deserve special mention are the Grahaṇa-nyāya-dīpikā of Parameśvara, which discusses the rationale of eclipse-computation, and the Grahaṇa-granthādi by Nīlakaṇṭha Somayāji, which is an elaborate disquisition on the tradition and rationale of computing eclipses etc.