Hipparchus

Hipparchus was a Greek astronomer, geographer and mathematician who worked in the second century BC, born around 190 BC in Nicaea in the Kingdom of Bithynia. He is considered the founder of trigonometry and developed early trigonometric tables, and he compiled the first extensive star catalog of the ancient West, listing roughly 850 stars. His most influential discovery for later cosmological thought was the precession of the equinoxes, the slow drift of the equinox points against the fixed stars, which he identified by comparing his own observations against earlier astronomical records. He also produced quantitative models of the motion of the sun and moon that survive in some form to modern times, and some ancient sources credit him with inventing the astrolabe and the armillary sphere. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/