Astronomer, Philosopher, Geographer (c.320 BC – c.260 BC)
Timocharis of Alexandria was the first astronomer verified in history to have recorded the position of some of the basic stars known today after having calculated their distance from certain points in the sky using mathematical scientific approach.
He lived during the reign of King Ptolemy I Soter and was a colleague of Aristyllus, a notable astronomer of his time. Together, they are credited as the first astronomers to have compiled an astronomic catalogue of the celestial bodies. Their work, although most of it lost, was used by pioneers in the field of astronomy such as Ptolemy and Hipparchus to compile the most extensively accurate star catalogue of the ancient world. Hipparchus further used Timocharis measurements as a basis for calculating the precession of the equinoxes, one of the greatest astronomical discoveries of mankind.
Timocharis wrote treatises on the lunar eclipses, recorded the exact date and time at night when he observed each star, as well as the lunar occultations at the time of the observation. He is also the first astronomer to use the Callippic calendar for his observations. Furthermore, he was the first to calculate the position of 12 fixed stars in the sky, with 6 more by Aristyllus as well as the positions of planet Venus. These calculations are considered accurate to this day.
As having created the very first star catalogue in world history, Timocharis was highly looked upon, as evident by Ptolemy and Hipparchus, who further continued his work, Hipparchus completing and perfecting it. It is unfortunate that almost the entirety of his work as been destroyed, with excerpt preserved by the two aforementioned astronomers in their works, in token of their admiration to Timocharis. Today, a crater on the Moon is named after him.
Bibliography:
- Georgakopoulos, Konstantinos. Ancient Greek Scientists. Georgiades: Athens, 1996. Print.
- “Timocharis.” Complete Dictionary of Scientific Biography. Encyclopedia.com. 31 Oct.2018 <https://www.encyclopedia.com>.
