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Most eminent Muslim astronomers include Al-Battani, al-Sufi, al-Biruni, and Ibn Yunus. They recorded the position of the sun, moon and the stars....
Most eminent Muslim astronomers include Al-Battani, al-Sufi, al-Biruni, and Ibn Yunus. Al-Battani (d 929) known to Europe as Albategni or Albatenius was the author of the Sabian tables (al-Zij al-Sabi), a work which had great impact on his successors, Muslim and Christian, in equal measure. His improved tables of the orbits of the sun and the moon comprise his discovery that the direction of the sun’s eccentric as recorded by Ptolemy was changing. This, in modern astronomy, means the earth moving in varying ellipse. He also worked on the timing of the new moons, the length of the solar and sideral year, the prediction of eclipses, and the phenomenon of parallax, carrying us `to the verge of relativity and the space age.
Al-Battani was also a pioneer in the field of trionometry. He was among the first, if not the first to use trigonometric ratios as we know them today. During the same period, Yahya Ibn Abi Mansour had completely revised the Zij of Almagest after meticulous observations and tests producing the famous Al-Zij al Mumtahan (the validated Zij). For details on his work see the proceedings of the 23rd Annual Conference on the History of Arabic Science 23rd-25th October 2001, Aleppo, Syria.
Belonging to the same era, Abd-al Rahman al-Sufi (903-986) made several observations on the obliquity of the ecliptic and the motion of the sun (or the length of the solar year). He became renowned for his observations and descriptions of the stars, their positions, their magnitudes (brightness) and their colour, setting out his results constellation by constellation. For each constellation, he provided two drawings, one from the outside of a celestial globe, and the other from the inside (as seen from the sky). Al-Sufi also wrote on the astrolabe, finding numerous additional uses for it (including where on is located, measuring distances and heights. . .). En par with other learned Muslims, he also pinpointed shortcomings of Greek astronomy.
Ibn Yunus (d 1009), in his observation endeavours included, amongst others more than 10, 000 entries of the sun’s position throughout the years using a large astrolabe of nearly 1.4 m in diameter. His work, in French edition, was centuries later an inspiration for Laplace in his determination of the `Obliquity of the Ecliptic’ and the `Inequalities of Jupiter and Saturn’s.’The famous european astronomer, Newcomb also used his observations of eclipses in the motions of the moon.