Ptolemy (c.90-c.168). Historical engraving of the Greek astronomer Claudius Ptolemaeus, also known as Ptolemy, who lived in the Greek culture of Roman Egypt. Ptolemy is one of the most famous astronomers of antiquity. The geocentric (Earth-centred) Ptolemaic system described in his Almagest documented previous Greek thought, and dominated Western science for over a thousand years. The Almagest summarised five centuries of Greek astronomy and represented the conventional view of the Universe until the Copernican revolution. He also worked out distances and sizes for the Sun and the Moon, compiled a catalogue of 1028 stars and described various astronomical instruments. From Weltall und Menscheit (Universe and Humanity), by Hans Kraemer (ca.