The History of Ptolemys Star Catalogue

The Almagest, a pivotal second-century text, established astronomy as a formal science and remained influential until the late Renaissance. It served as the foundation for European astronomical knowledge, incorporating refinements from Arabic scholars and shaping the work of Copernicus and Kepler. The text introduced crucial concepts such as the separation of sidereal and tropical years, celestial coordinate systems, and classifications of celestial brightness, many of which continue to underpin modern astronomy. Its legacy endures through the theories that evolved from its principles.