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HIPPARCHUS of Nicea (190-120 B.C.)
Greek astronomer and mathematician. Considered the greatest astronomer of ancient times. Developed a system of planetary motion with the Earth at the center. This system was later refined by Ptolemy. Used data from a total eclipse of the sun and parallax to determine correctly the distance and size of the moon. The same data gave values for the distance and size of the sun an order of magnitude smaller than there actual values.