Abu Jafar Muhammad ibn Hasan Khazini (Persian: ابوجعفر خازن خراسانی; 900–971), also called Al-Khazin, was an Iranian Muslim astronomer and mathematician from Khorasan. He worked on both astronomy and number theory.
Al-Khazin was one of the scientists brought to the court in Ray, Iran by the ruler of the Buyid dynasty, Adhad ad-Dowleh, who ruled from 949 to 983 AD. In 959/960 Khazini was required by the Vizier of Ray, who was appointed by ad-Dowleh, to measure the obliquity of the ecliptic.
One of Al-Khazin’s works Zij al-Safa’ih (“Tables of the disks of the astrolabe”) was described by his successors[who?] as the best work in the field and they make many references to it. The work describes some astronomical instruments, in particular an astrolabe fitted with plates inscribed with tables and a commentary on the use of these. A copy of this instrument was made, but it vanished in Germany at the time of World War II. A photograph of this copy was taken and examined in D.A. King’s New light on the Zij al-Safa’ih of Abu Ja’far al-Khazin, Centaurus 23 (2) (1979/80), 105-117.
Al-Khazin also wrote a commentary on Ptolemy’s Almagest in which he gives nineteen propositions relating to statements by Ptolemy. He proposed a different solar model from Ptolemy’s.