1911 Encyclopædia Britannica/Albategnius
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 55″ Perhaps independently of Aryabhatta (born at Pātaliputra 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 astronomical chronology. Albategnius takes the highest rank among Arab astronomers.