Parahita is a system of astronomy prevalent inKerala andTamil Nadu,India. It was introduced by the Kerala astronomerHaridatta, (c. 683 AD[1]). Nilakantha Somayaji (1444–1544), in hisDr̥kkaraṇa, relates how Parahita was created based on the combined observations of a group of scholars who had gathered for a festival atTirunāvāy on the banks of theBhāratappuzha River. TheSanskrit etymology literally means "for the benefit of the common man", and the intention was to simplify astronomical computations so that everyone could do it.
Parahita is a significant step in the simplification of thesiddhantic tradition. Of the two texts of the system,Grahacāranibandhana andMahāmārganibandhana, only the former is known. The system simplified the computational cycle of theAryabhatiya by introducing a sub-aeon of 576 years and introduced a zero correction calledVāgbhāva based on which the system worked accurately around the time of Haridatta.[2]
Also Haridatta simplified the representation of numerals from the cumbersome notation ofAryabhata to thekatapayadi system which gained wide currency in laterKerala mathematics. In the katapayadi system, numerals may be represented by various letters so that the large numerical tables required for astronomical computations could be represented as verses and memorized.
The workGrahacāranibandhana-sangraha (932 AD) gives further details of the parahita technique. The methods were retained but some of the constants downgraded byParameshvara in his DrggaNita (1483), and also byAchyuta Pisharati in hisrAsigolasphuTanIti (1600).