Almagest of Ptolemy

The Almagest by Ptolemy is an ancient astronomical text that explains how the planets, Sun, and Moon move in the sky. Ptolemy developed a geocentric model, placing Earth at the center, with planets moving in complex paths called epicycles and deferents to explain observed motions. The book includes star charts, mathematical models, and predictions of planetary positions, providing a comprehensive framework for astronomy in the Greco-Roman world. It remained influential for centuries and contributed significantly to the development of celestial mechanics and our understanding of the cosmos during that era.