Hipparchus compiles a star catalogue
Hipparchus compiles a star catalogue
Overview
Working on Rhodes around 150 BCE, Hipparchus measured the positions and brightnesses of roughly 850 stars, producing the first known systematic star catalogue of the ancient world. Comparing his positions with earlier records, he discovered the precession of the equinoxes — the slow drift of the celestial pole that shifts the coordinates of every star over centuries. He also introduced the magnitude scale for stellar brightness and championed quantitative observation as the foundation of astronomy.