Hipparchos of Nicaea

An astronomer in a fanciful Egyptian landscape

looking towards the Moon in Cancer. Around

him are an armilliary, an astrolabe, a meridian

sphere and a celestial globe.

Hipparchos of Nicaea (c. 190 – c. 120 BCE) was one of the two great astronomers of antiquity and certainly the greatest before Ptolemy. He was an early pioneer of the mathematics necessary for the development of positional astronomy, an assiduous and exacting observer, the compiler of the first known star catalogue of any size, the author of several books on astronomy (only one of which survives in its entirety, more or less), one of the first Greeks to make systematic use of Babylonian astronomical data, the first Greek to tackle the motions of the Sun and Moon in mathematical detail, and the discoverer of the phenomenon known as the precession of the equinoxes.

He was born in the Greek colony of Nicaea in the small kingdom of Bithynia, which is in the northwestern part of modern day Turkey, and probably spent the latter part of his life on the island of Rhodes. The large lunar crater Hipparchus (diameter 144 km) is named after him. Below are links to various aspects of Hipparchos' life and work.

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1. Life and Times
2. Works
3. Commentary on the Phenomena of Aratos and Eudoxos
4. Star Catalogue 
5. Precession of the Equinoxes
6. The Mathematics of Hipparchos
7. Theory of the Sun
8. Theory of the Moon
9. Hipparchos and Ptolemy

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Last updated 14/06/20