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- GREEK-EGYPTIAN PTOLEMY: 100-165 AD
-
- Born a Greek, Claudius Ptolemy spent much of his
- adult life in the city of Alexandria (Egypt). His
- influence on astrology was considerable. He
- recognized four astrological aspects: Opposite (180
- degrees), Trine (120 degrees), Square (90 degrees),
- and Sextile (60 degrees).
- Ptolemy prefaced his famous Tetrabiblos with a
- defense of astrology that proved influential. He
- cataloged 1028 stars in perhaps the first star
- catalog and described 48 constellations, of which 47
- are known by the same name today.
- In his Almagest, Ptolemy developed sophisticated
- lunar and planetary theories. He accounted for the
- chief irregularity of the Moon apparent motion,
- leading to the prediction of eclipses. His elaborate
- epicycle model predicted the location of the Moon
- within 10 minutes of arc in the sky (well within the
- precision of the instruments used to measure the
- Moon's position at that time).
- Ptolemy also described the motions of the planets
- in the Almagest. His work went largely unchallenged
- and was widely accepted until the Renaissance.
-