Hipparchus

American  

[hi-pahr-kuhs] / hɪˈpɑr kəs /

noun

1. died 514 b.c., tyrant of Athens 527–514.

2. c190–c125 b.c., Greek astronomer.

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Hipparchus ¹ British  

/ hɪˈpɑːkəs /

noun

1. a large crater in the SW quadrant of the moon, about 130 kilometres in diameter

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Hipparchus ² British  

/ hɪˈpɑːkəs /

noun

1. 2nd century _bc , Greek astronomer. He discovered the precession of the equinoxes, calculated the length of the solar year, and developed trigonometry

2. died 514 _bc , tyrant of Athens (527–514)

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Hipparchus Scientific  

/ hĭ-pär′kəs /

1. Greek astronomer who mapped the positions of about 850 stars in the earliest known star chart (129 bce). His observations of the heavens formed the basis of Ptolemy's Earth-centered model of the universe. He was also a pioneer of trigonometry.

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Example Sentences

The researchers were able to use this to check when the ancient astronomer must have made his observations, and found that the coordinates fit roughly 129 BC—during the time when Hipparchus was working.

From Scientific American • Oct. 20, 2022

And whereas Ptolemy based his coordinate system on the ecliptic, Hipparchus used the celestial equator, a system more common in modern star maps.

From Scientific American • Oct. 20, 2022

The relationship between Hipparchus and Ptolemy has always been murky.

From Scientific American • Oct. 20, 2022

Almagest does not deal exclusively with Ptolemy’s own work; it includes a discussion of the astronomical achievements of the past, principally those of Hipparchus.

From Textbooks • Oct. 13, 2016

This was in fact the method used by a Greek astronomer, Hipparchus of Nicaea, in 150 B.C. to work out the Moon’s distance from Earth.

From "A Short History of Nearly Everything" by Bill Bryson