home   :    index    :    ancient Greece

Hipparchus of Nicaea


Hipparchus
Hipparchus
Hipparchus of Nicaea (second century BCE): Greek astronomer, discoverer of the precession.

The stellar catalogue made by Hipparchus of Nicaea contains observations that can be dated to 162-128 BCE, and this gives us an indication about the period in which he lived. Unfortunately, this is about everything we know about this astronomer, who was the first to discover the precession, i.e. the slow reorientation of the earth's axis. He was able to do this because he possessed the sky map of Eratosthenes and age-old Babylonian observations and knew the theories of the great Kidinnu

Unfortunately, Hipparchus ignored Kidinnu's calculation of the length of the solar year. The Greek astronomer's estimate had an error of 6½ minutes, whereas the Babylonian was only 4½ short of the real length of the year. Nevertheless, Hipparchus was able to improve the calendar. Another triumph was the accurate calculation of the distance to the moon, and the improvement of the world map of Eratosthenes.

Ancient-Warfare.com, the online home of Ancient Warfare magazine
 
This brief article has been written to offer background information
to the real articles on Livius.Org. One day, this webpage will be
improved. A list of completed articles can be found here.
© Jona Lendering for 
Livius.Org, 2005
 home   :    index    :    ancient Greece