Abu Jafar Khazeni

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Abu Jafar Muhammad ibn al-Hasan Al-Khazini (900 - 971), was a Persian astronomer and mathematician from Khorasan.

He worked on both astronomy and number theory.

Khazini 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 Adhad 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 as the best work in the field and they make many a reference to it. The work describes some astronomical instruments, in particular it describes an astrolabe fitted with plates inscribed with tables and a commentary on the use of these. A copy of this instrument was made but 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.

Khazeni also wrote a commentary on Ptolemy's Almagest in which he gives 19 propositions relating to statements by Ptolemy. He also proposed a different solar model from that of Ptolemy.