One of the famous astronomers in the 9th century. Born in 805at Ferghana (present Uzbekistan), he worked in Baghdad, where he was connected to the group of scholars led by the brothers Banu Musa. Later he moved to Cairo, where he composed a very important treatise on the astrolabe around 856. There he also supervised the construction of the large Nilometer on the island of al-Rawda (in Old Cairo) in 861. Al-Farghani died around 880.
He was involved in the measurement of the diameter of the Earth together with a team of scientists under the patronage of Caliph al-Ma'mūn in Baghdad. His textbook Elements of astronomy on the celestial motions, written about 833, was translated into Latin in the 12th century and remained very popular in Europe until the time of Regiomontanus. In the 17th century the Dutch orientalist Jacob Golius published the Arabic text on the basis of a manuscript he had acquired in the Near East, with a new Latin translation and extensive notes. The Alfraganus crater on the Moon was named after him.