SR-03-Ptolemy - in his Syntaxis later known as the...

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Ptolemaic Astronomy Almost everyone in the ancient world took the common sense view that the Earth is stationary at center of universe, and that the Sun, planets, and stars circle around it. Aristarchus of Samos (310–230 BC) and a few others suggested that the Earth circles the Sun, but very few accepted this seemingly absurd idea. Astronomers sought system of circles to account for the observed motions of the heavenly bodies, particularly the planets’ retrograde motion : the periodic reversal of their usual east to west motion through the stars of the zodiac. Ptolemy gave a full treatment of the epicycle theory
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Unformatted text preview: in his Syntaxis , later known as the Almagest (Latinized from the Arabic for ‘the greatest’), c. AD 150. Ptolemy used epicycles, eccentrics (off center orbits), and the equant : a point, away from the center of a planet’s orbit, around which the planet moves through equal angles in equal times. Eudoxus (c. 410–350 BC): devised a system of nested spheres; adopted by Aristotle. But most ancient astronomers preferred geocentric/geostatic epicycle system: Hipparchus (c. 190–120 BC) Claudius Ptolemy of Alexandria (c. AD 100–160) equant point Earth A C D B Ptolemy's equant center...
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This note was uploaded on 12/03/2011 for the course HISTORY 322D taught by Professor Hunt during the Fall '11 term at University of Texas.

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