Ptolemy was a Greek astronomer, astrologer, mathematician and geographer who lived and worked in Alexandria in Ancient Egypt, in the second century AD.
His work ‘Almagest,’ is one of the most important works in ancient astronomy. It covers the motion of sun, moon, and the planets around the Earth. It also contains a catalogue of stars with their brightness on a logarithmic scale.
Ptolemy’s description of the universe was accepted by the astronomical community for more than a thousand years. Ptolemy’s second important work is called ‘Geography.’ It is a thorough discussion of the geographic knowledge of the Greco-Roman world.
Ptolemy’s treatise on astrology was influential because of its practical treatment of astrology. Ptolemy discarded practices that did not have a logical basis, and also believed that astrology was not a completely reliable science.