| Hipparchus | |
|---|---|
| Birthplace | Nicaea |
| Occupation | astronomer, mathematician, geographer |
Hipparchus, the preeminent ancient Greek astronomer, lived from approximately 190 b.c.e. to 120 b.c.e. He developed trigonometry, recorded the location of more than a thousand stars, and originated the idea of latitude and longitude. He is said to have discovered the phenomenon known as the precession of the equinoxes. Hipparchus was also a practicing astrologer.
Born circa 180-190 B.C. in Nicaea; died 125 B.C. in Rhodes. Ancient Greek scientist; one of the founders of astronomy.
Hipparchus carried out the first systematic observations and investigations of the sky. He worked out the theory and compiled tables of the motions of the sun and moon, as well as a table of solar eclipses. This work was based on a geocentric system; Hipparchus rejected the idea of heliocentricism as a hypothesis without sufficient proof. He described lunar motion at full and new moon and rather accurately estimated the distance between the moon and the earth. Circa 129-127 B.C. he compiled a catalog, which was enormous for those times, of the positions of 850 stars, classifying the stars according to brightness into a system of six magnitudes. Comparing his positions of the stars with earlier ones (third century B.C.), Hipparchus discovered the phenomenon of precession and rather accurately estimated its magnitude. In connection with this, he determined the length of the tropical year (with an error of no more than 6 minutes) and its difference from the sidereal year (15 minutes; at present, 20 minutes). Hipparchus determined the inclination of the equator to the ecliptic, with an error of 5’. He introduced the geographical coordinates of latitude and longitude. His works in the original have not been preserved. The principal source of information on his work is Ptolemy’s Almagest.
A. I. EREMEEVA