Hipparchus

Hipparchus was an ancient Greek astronomer and mathematician who lived around 190-120 BCE. He is renowned for creating one of the earliest comprehensive star catalogs, mapping over 850 stars, and for developing techniques to measure celestial distances and positions. Hipparchus also pioneered the use of trigonometry in astronomy and discovered the precession of the Earth's axis—a slow wobble that changes the position of stars over time. His work laid the foundational principles for later astronomers, including Ptolemy, and significantly advanced our understanding of the heavens.