Al-Batani, also know as Albategnius (circa 850 - 929), was an Arab prince and astronomer. His full name is Abu Abdallah Mohammad ibn Jabir ibn Sinan al-Raqqi al-Harrani al-Sabi al-Battani, hence the usual shortening. His name derives 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 Pataliputra on the Ganges in 476 AD), 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, annotated by Regiomontanus. A reprint appeared at Bologna in 1645. The original manuscript is preserved at the Vatican; and the Escorial Library possesses in manuscript a treatise by him, of some value, on astronomical chronology.