Jyotihshastra: Astral and Mathematical Literature c4.42

c4.42

The five main pakṣas that developed in India are the Brāhma,²⁰ the Ārya,²¹ the Ārdharātrika,²² the Saura,²³ and the Gaṇeśa;²⁴ the Brāhma and the Saura both were revised in the medieval period. There are, as well, some texts which belong to no pakṣa,²⁵ and some derived from Islam.²⁶ These find their expression in various literary forms, which were classified under three main headings from the seventh century on. Siddhāntas are comprehensive treatises deducing mean motions from the beginning of the Kalpa or the current Kaliyuga; karaṇas are more concise expositions of astronomy in which the mean longitudes for a time close to the date of composition are given, and the mean longitudes at later times are computed therefrom; and koṣṭhakas are sets of astronomical tables, for determining planetary positions or for solving other problems in astronomy. There are as well many specialized works on aspects of astronomy, of which the most important group is on observational instruments (yantra).