c.190 — c.120 BC
Hipparchus or Hipparch was a Greek astronomer who was born in Asia Minor.
Hipparchus drew up the first catalog of the stars, showing their brightness and position. He also founded trigonometry and discovered the precession of the equinoxes. Comparing star observations of different years he noticed that the stars had shifted eastward.
He found that while their celestial longitude increased slightly their latitude did not change. He explained these facts by a slow forward motion of the equinoxes.