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An edition in Latin of the Almagestum in 1515. The Almagest (/ ˈ æ l m ə dʒ ɛ s t / AL-mə-jest) is a 2nd-century mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy (c. AD 100 – c. 170) in Koine Greek. [1]
Claudius Ptolemy was a mathematician who worked in the city of Alexandria in Roman Egypt in the 2nd century AD, deeply examining the shape and motion of the Earth and other celestial bodies. Ptolemy's most important work was the Almagest (also known as the Mathematical Composition ) and he composed other works such as the Hypotheses ...
The Sun-centered positions displayed a cyclical motion with respect to time but without retrograde loops in the case of the outer planets. [dubious – discuss] In principle, the heliocentric motion was simpler but with new subtleties due to the yet-to-be-discovered elliptical shape of the orbits. Another complication was caused by a problem ...
Hence their motions are eternal and perfect, and the perfect motion is the circular one, which, unlike the earthly up-and down-ward locomotions, can last eternally selfsame - an early predecessor to Newton's First Law of Motion. Aristotle theorized that aether did not exist anywhere on Earth, but that it was an element exclusive to the heavens.
Ptolemy's work the Almagest had wide and long-lasting acceptance and influence for over a millennium. He gave a geometrical lunar theory that improved on that of Hipparchus by providing for a second inequality of the Moon's motion, using a device that made the apparent apogee oscillate a little – prosneusis of the epicycle.
Aristotelian physics is the form of natural philosophy described in the works of the Greek philosopher Aristotle (384–322 BC). In his work Physics, Aristotle intended to establish general principles of change that govern all natural bodies, both living and inanimate, celestial and terrestrial – including all motion (change with respect to place), quantitative change (change with respect to ...
Ptolemy shifted the Earth away from the center of the deferent and introduced another point, the equant, equidistant to the deferent's center on the opposite side of the Earth. [9] The Vicarious Hypothesis uses a circular orbit for Mars and reintroduces a form of the equant to describe the motion of Mars with constant angular speed. [4]
Ptolemy's model of astronomy was used as a technical method that could answer questions regarding astrology and predicting planets positions for almost 1,500 years, even though the equant and eccentric were regarded by many later astronomers as violations of pure Aristotelian physics which presumed all motion to be centered on the Earth. It has ...