1. Hipparchus - Noun
2. Hipparchus - Proper noun
Greek astronomer and mathematician who discovered the precession of the equinoxes and made the first known star chart and is said to have invented trigonometry (second century BC)
Source: WordNetAccording to Ptolemy, Hipparchus measured the longitude of Spica and Regulus and other bright stars. Source: Internet
Although he wrote at least fourteen books, almost nothing of Hipparchus ' direct work survived. Source: Internet
Anyway, Hipparchus found inconsistent results; he later used the ratio of the epicycle model (3122+1/2 : 247+1/2), which is too small (60 : 4;45 sexagesimal). Source: Internet
Apparently Hipparchus later refined his computations, and derived accurate single values that he could use for predictions of solar eclipses. Source: Internet
Based partly on data taken from Pytheas, Hipparchus correlated cubits of the sun's elevation at noon on the winter solstice, latitudes in hours of a day on the summer solstice, and distances between latitudes in stadia for some locations. Source: Internet
Chartrand, p. 172. It was not separated from Centaurus until Hipparchus of Bithynia named it Therion (meaning beast) in the 3rd century BC. Source: Internet