Abu Ja'far al-Khazin

For the 12th century physicist and astronomer, see Al-Khazini.

Al-Khazin
ابوجعفر خازن خراسانی
Born	900
Died	971
Academic work
Era	Islamic Golden Age
Main interests	Mathematics, astronomy

Abu Jafar Muhammad ibn Husayn Khazin (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. In 959/960, Khazin was required to measure the obliquity of the ecliptic by the vizier of Ray, who was appointed by ad-Dowleh.

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 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 during World War II. A photograph of this copy was taken and examined by the historian David King in 1980.

Al-Khazin also wrote a commentary on the Roman polymath Ptolemy's Almagest in which he gives 19 propositions relating to statements by Ptolemy, and proposed a different model of the cosmos.

Mathematics

Al-Khazin was the first to formulate and solve the congruum problem.

Sources

• Dold-Samplonius, Yvonne (1981). "Al-Khāzin, Abū Ja'far Muḥammad Ibn Al-Ḥasan Al-Khurāsānī". In Gillispie, Charles Coulston; Holmes, Frederic Lawrence (eds.). Dictionary of Scientific Biography. Vol. 7 & 8. New York: Scribner. OCLC 755137603.
• King, David A. (2007). "New Light on the Zīij al-Safāa'ih of Abū Jacfar al-Khāzin". Centaurus. 23 (2): 105–117. doi:10.1111/j.1600-0498.1979.tb00226.x. ISSN 0008-8994 – via ResearchGate.
• Selin, Helaine (1997). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Berlin; New York: Springer Nature. ISBN 978-1-4020-4960-6.

Further reading

• Calvo, Emilia (2007). "Khāzin: Abū Jaʿfar Muḥammad ibn al-Ḥusayn al-Khāzin al-Khurāsānī". In Thomas Hockey (ed.). The Biographical Encyclopedia of Astronomers. New York: Springer. pp. 628–9. ISBN 978-0-387-31022-0. (PDF version)
• Pingree, David (1983). "Abū Jaʿfar Ḵāzen". Encyclopædia Iranica.
• Rashed, Roshdi (1996). Les Mathématiques Infinitésimales du IXe au XIe Siècle 1: Fondateurs et commentateurs: Banū Mūsā, Ibn Qurra, Ibn Sīnān, al-Khāzin, al-Qūhī, Ibn al-Samḥ, Ibn Hūd. London: Islamic Heritage Foundation. pp. 737–778, 779–833 (Texte et Traduction: Abū Ja‘far al-Khāzin, Transcrit du commentaire du premier livre de l’Almageste Min al-sharḥ li-al-maqāla al-ülā min al-Majisṭī). ISBN 1-873992-18-1.