Hipparchus

[hi-pahr-kuhs]

noun

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

2. c190–c125 b.c., Greek astronomer.

Hipparchus

¹

/ 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)

Hipparchus

²

/ hɪˈpɑːkəs /

noun

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

Hipparchus

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.

Example Sentences

The first person we know did this was Greek polymath Hipparchus, who created a star map noting the brightness of various stars more than two millennia ago.

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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.

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Astronomers measure brightness by using a system called apparent magnitudes, credited to the ancient Greek polymath Hipparchus, in which larger numbers correspond to fainter objects.

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“The problems are very beautiful,” the astronomer wrote, of his Hipparchus study, in 1619.

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In light of Hipparchus and Ptolemy’s extraordinarily successful predictive theories, the goal of astronomy was to find the right combination of circles to describe the motion of the heavenly bodies around the Earth.

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