Reference Work Entry

The Biographical Encyclopedia of Astronomers

pp 935-937

Ptolemy

  • Norriss S. Hetherington
Flourished Alexandria, (Egypt), second century
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Hundreds of years of Greek geometrical astronomy were systematized, with rigorous demonstrations and proofs, by Claudius Ptolemaius. His intent was to do for applied mathematics what Euclid had done for pure mathematics (geometry). Ptolemy produced handbooks containing all that was known about astronomy, optics, geography, astrology, musical theory, geometrical constructions using spherical projection, the structure and size of the Universe, and mechanics. Although his primary goal was to summarize what was already known, Ptolemy also advanced astronomical knowledge so far as to earn for himself a reputation as the greatest astronomer of the ancient world. He showed how, based upon observation and empirical data, geometrical models could be constructed that simulated nature. His astronomical textbook surpassed all that had gone before and dominated future astronomy for well over a millennium. In replacing much of previous astronomy, however ...

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