Astronomy History

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Paul A. Heckert

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Astronomy History

Ptolemaic Geocentric Astronomy

By: Paul A. Heckert

Ptolemy's geocentric astronomical system used four geometric devices, the deferent, epicycle, eccentric, and equant, to explain the observed motions of the planets. more...

Ptolemy, Astronomy, & Almagest

By: Paul A. Heckert

Ptolemy's geocentric astronomical system placed Earth at the center of the universe and he was considered the ultimate authority in astronomy for about 1400 years. more...

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