Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s5.57

v2.c12.s5.57

He has assumed 3600 as the radius and 23° 35′ as the maximum declination; he has given tables of sines, declinations and sky diameters for each degree and has given the length of the shadow cast by a gnomon of seven inches for each degree of altitude, varying from 0° to 90°. The commentator has given the latitudes of about 75 cities. The author of the work has given sāyana longitudes and latitudes of 32 stars which are useful for observation, and has mentioned 54″ per year as the precessional motion. It is not possible to describe the construction of the instrument, Yantra Rāja, briefly, and hence it is not given here. With the help of this instrument the following things can be found directly from observation :—the altitude, zenith distance, longitude and latitude of the Sun ; planets and stars ; distance in degrees between any two celestial bodies, the latitude of a place, the ascending sign and the time and length of the day. There is a commentary on this work written by Yajñeśwara in Śaka 1764.