ALBATEGNIUS (c. 850-929)  , an Arab prince and astronomer, correctly designated Mahommed ben Gebir al Batani, his surname being derived from his native town, Batan in Mesopotamia . From his observations at Aracte and Damascus, where he died, he was able to correct some of Ptolemy's results, previously taken on trust . He compiled new tables of the sun and moon, long accepted as authoritative, discovered the movement of the sun's apogee, and assigned to annual precession the improved value of 550 . Perhaps independently of Aryabhatta (born at Pataliputra on the Ganges 476 A.D.), he introduced the use of sines in calculation, and partially that of tangents . His principal work, De Motu Stellarum, was published at Nuremberg in 1537 by Melanchthon, in a blundering Latin translation by Plato Tiburtinus (fl . 1116), annotated by Regiomontanus . A reprint appeared at Bologna in 1645 . The original MS. is preserved at the Vatican; and the Escorial library possesses in MS. a treatise of some value by him on astronomicalchronology . Albategnius takes the highest rank among Arab astronomers . See Houzeau, Bibliographic astronomique, i . 467; M . Marie, Histoire des sciences, ii .

113; R .

Wolf, Geschichte der Astronomie; p . 67; Delambre, Hist. de l'astr. au moyen age, ch. ii.; Phil . Trans., 1693 (913), where E . Halley supplies corrections to some of the observations recorded in De Motu Stellarum .