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Definition: Almagest from Brewer's Dictionary of Phrase and Fable

The English form of the Arabic name, al-majisti (from Greek megistē, ‘greatest’), given to Ptolemy's Mathematikē Suntaxis, his classic astronomical treatise in 13 books, of the mid-2nd century ad. An Arabic translation was made about 820. In the third book the length of the year was first fixed at 365 days. His geocentric astronomy lasted until the introduction of the COPERNICAN SYSTEM.

Summary Article: Almagest from The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide

Book compiled by the Egyptian astronomer Ptolemy during the 2nd century, which included the idea of an Earth-centred universe; it was translated into Arabic in the 9th century. Some medieval books on astronomy, astrology, and alchemy were given the same title.

Each of the 13 sections of the book deals with a different branch of astronomy. The introduction describes the universe as spherical and contains arguments for the Earth being stationary at the centre. From this mistaken assumption, it goes on to describe the motions of the Sun, Moon, and planets; eclipses; and the positions, brightness, and precession of the ‘fixed stars’. The book drew on the work of earlier astronomers such as Hipparchus.

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