Ibn Yunus

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Ibn Yunus

 

Born 950; died 1009. Arab astronomer.

Ibn Yunus conducted extensive astronomical observations at an observatory near Cairo and compiled astronomical tables of the motion of the sun, moon, and planets, which for about two centuries were the best tables of their kind. He also compiled trigonometric tables. Ibn Yunus refined the values of the precessional constant and the angle of inclination of the ecliptic to the equator. He perfected the methods of the solution of plane and spherical triangles (the method of auxiliary angles).

REFERENCE

Berry, A. Kratkaia istoriia astronomii, 2nd ed. Moscow-Leningrad, 1946. (Translated from English.)
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His detractors at the court, especially al-Rabi' ibn Yunis, drummed up the charge that the son was a zindiq and although the son was willing to denounce zandaqa, he was nonetheless put to death (al-Rabi' actually suggested that Abu 'Ubaydallah should perform the execution of his son).