HIPPARCHUS

A Greek mathematician, the founder of scientific astronomy, born at Nicaea in Bithynia, lived chiefly at Rhodes and Alexandria, and died about B.C. 125. He discovered the precession of the equinoxes, settled more accurately the length of the solar year, as also of the revolution of the moon, and the magnitude and distances of the heavenly bodies. He placed mathematical geography on a firmer basis, by teaching the application of the latitude and longitude of the stars to marking the position of places on the surface of the earth. Of his numerous writings we only possess his commentary on the Phoenomena of Eudoxus and Aratus, and a catalogue of 1,026 fixed stars.