Ibn Yunus

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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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).


Berry, A. Kratkaia istoriia astronomii, 2nd ed. Moscow-Leningrad, 1946. (Translated from English.)
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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As demonstrated by the Ibn Yunus discovery earlier this year, the Kafr el Sheik horizon is an excellent quality productive sequence.
The problem was also taken up by Muslim astronomers, including the illustrious Al Khwarizmi (9th century), Al Battani (9th-10th century), Ibn Yunus (11th century), and Al Tusi (13th century), and they came up with prediction criteria based on the angle between the moon and the sun in the sky (9 to 11 degrees) on that evening.
His study of metaphysics began when he followed courses taught by the famous Nestorian, Christian translator, and student of Aristotle, Matta ibn Yunus. So introduced, he left Baghdad for Constantinople to further his study of philosophy and Greek science, returning to Baghdad after eight years.
In the Cairo manuscript, for example, a biography for Ibn Yunus is incomplete, but it is far longer and essentially complete in fols.
Can we isolate the contribution of Islamic scholars such as Alhazen, who made significant contributions to the principles of optics; Al-Kindi, who discussed the theory of relativity within the scope of physics for the first time; Al-Biruni, who correctly calculated the densities of many minerals and Ibn Yunus, who invented the pendulum as a timing device and established rules of physics before Galileo from the enlightenment of the West?
Ibn Yunus or Abu al-Hasan 'Ali bin 'Abd al-Rahman bin Ahmad bin Yunus al-Sadafi al-Misri was a scholar of astronomy who was under the patronage of Caliph al-Hakim of the Fatimid Dynasty in Egypt.
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We find excellent scientists such as the mathematician and theologian Kamal al-Din ibn Yunus and the professors of the legal School of Baghdad, al-Nizamiyyah, among those whom Goldziher classifies among "the orthodox".
The astronomer Ibn Yunus had waited for over an hour until the first stars could be recognised in the evening twilight.
As a member of the International Astronomical Union's Task Group for Lunar Nomenclature, El Baz proposed naming lunar features after historic Arab scientists, such as astronomer Ibn Yunus. Over 36 of his proposals were accepted, leading one British astronomer to complain that the moon was "becoming an Arabian graveyard".
Shaikh Zayed was pleased that the map showed the names of the ancient Arab scientists who were around during the golden era of Islam such as Abu Al Fada, Beruni, Al Battani and Ibn Yunus and others," he said.
Apart from his appearance in Daftary's overview of hidden Imams and Mandis in Ismaili history, however, he is represented here only by a sixteenth-century picture of the astronomer/astrologer Ibn Yunus presenting his astronomical tables to the caliph.