Jyotihshastra: Astral and Mathematical Literature c4.s2.8

c4.s2.8

The Pait. is cast in the form of a lecture by Brahmā to Bhṛgu. Its first two chapters deal with astrology. Chapter three discusses time-measurements, the parameters of the planetary system, Sines and Versines, the declination of the Sun and latitudes of the planets, gnomon-problems, right and oblique ascensions, a star catalogue, the Greek-letter phenomena of the planets, and the calendar; this confused congeries is also indicative of the age of the Pait. as later *siddhāntas* are arranged far more systematically. Chapter four covers the computation of the *ahargaṇa* (number of days lapsed since epoch), the astrological lords of the years, days, and *parvans*, the computation of the mean and true longitudes of the planets and of their latitudes, and the times of the occurrences of the planets’ first and second stations. Chapter five deals with the earth’s shadow (for lunar eclipses), *saṅkrāntis*, *tithis*, *karaṇas*, *yogas*, and the *vaidhṛta* and *vyatīpāta* *pātas*. Chapter six covers some problems in spherical trigonometry and their solution by means of analemmata. Chapter seven is devoted to the computation of the ascendant and of the time lapsed since sunrise. Chapter eight presents the method of computing the times and longitudes of the first and last visibilities of the planets and fixed stars. And chapter nine gives rules for computing the illumination of the Moon and longitudinal and latitudinal parallax (for solar eclipses). Several of these rules are incomplete or wrong as presented in the two editions, and only the preliminaries for computing lunar and solar eclipses are given. One suspects that the original Pait. was a more competent work than what we now possess of it.