Ptolemaic system developed in ancient Greece:

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Ptolemaic system developed in ancient Greece
Geometrical model of universe used to
discover the precession of the equinoxes
precession of the equinoxes
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Looking down on celestial sphere from North
celestial pole
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• armillary sphere

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observatory at Samarkand
Tycho Brahes observatory in Denmark
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What is an ellipse?
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Ellipses of same major axis but different
eccentricity