From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 39-40

Courtesy of

Amājūr Family

İhsan Fazlıoğlu

Flourishedlate 9th/early 10th century

The Amājūr Family includes Abū al‐Qāsim ʿAbd Allāh ibn Amājūr al‐Turkī al‐Harawī, his son Abū al‐asan ʿAlī, a certain ʿAlī ʿAbd Allāh ibn Amājūr, and Abū al‐ asan's freed slave Mufli ibn Yūsuf. They are known for their extensive observational astronomical work, and for compiling the results of these observations into several zījes (astronomical handbooks). It is said that they were assisted in their observations by a large group of people.

There is little information about the Amājūr Family's lives in either historical or modern sources. There is also some ambiguity about their names and identities. Ibn Yūnus refers to the father as al‐Turkī and mentions another person as having assisted him in doing the astronomical observations along with his son and his slave. Ibn al‐Qifī, though, refers to Abū al‐Qāsim as al‐arawī from the city of Herat; he informs us that the son Abū al‐asan ʿAlī was raised by his father, who had educated him in the sciences. Ibn al‐Qifī considers ʿAlī ibn Amājūr as a separate person, and not necessarily related to Abū al‐Qāsim. Both Ibn al‐Nadīm and Ibn al‐Qifī believe that the family hailed from Farghāna.

The Amājūr Family carried out their astronomical observations between 885 and 933; most of their work took place in Baghdad and, to a lesser extent, in Shīrāz. Their long‐term astronomical observations, which lasted 30–50 years, involved work on the fixed stars, the Sun, the Moon, and the planets. There has been speculation that there was an observatory of some sort in connection with the Amājūr Family based on their needs for precise observations and for recording their results. There is also a report that a large group aided the Amājūr Family with their observations. Ibn Yūnus, who records observations of solar and lunar eclipses and planetary positions by the Amājūr Family, indicates that they carried out their observations at a raised, flat place with a view, called a “ārum” or “āruma.” On the basis of his research, Caussin concludes that there was an observatory.

There is little information regarding the instruments that were used by the Amājūr Family. However, ʿAbd Allāh ibn Amājūr mentions one he used to observe a solar eclipse on 18 August 928 with Abū al‐asan and Mufli. From the information provided on this observation, Caussin determined that the instrument had to be quite large given the preciseness of the measurements.

ʿAbd Allāh ibn Amājūr was apparently well known in his time, and he wrote a number of books, most of them zījes. According to D. King, ʿAlī ibn Amājūr worked on improving Khwārizmī's (9th century) prayer tables, providing the approximate times for different latitudes. ʿAlī ibn Amājūr also prepared a prayer table for Baghdad, based upon precise trigonometrical calculations.

Selected References

Brockelmann, Carl (1937). Geschichte der arabischen Litteratur. 2nd ed. Suppl. 1. Leiden: E. J. Brill, p. 397.

Caussin de Perceval, A. P. (1803–1804). “Le livre de la grande table Hakemite.” Notices et extraits des manuscrits de la Bibliothèque nationale 7: 16–240, esp. pp. 120–178.

Ibn al‐Nadīm (1970). The Fihrist of al‐Nadīm: A Tenth‐Century Survey of Muslim Culture, edited and translated by Bayard Dodge. 2 Vols. Vol. 2, p. 662. New York: Columbia University Press.

Ibn al‐Qifī. Kitāb Ikhbār al‐ʿulamāʾ bi‐akhbār al‐ukamāʾ. Cairo, 1326 (1908), pp. 149, 155, 157.

Kennedy, E. S. (1956). “A Survey of Islamic Astronomical Tables.” Transactions of the American Philosophical Society, n.s., 46, Pt. 2: 121–177, esp. 125, 134–135. (Reprint, Philadelphia: American Philosophical Society, 1989.)

King, David A. (1996). “Astronomy and Islamic Society: Qibla, gnomonics and timekeeping.” In Encyclopedia of the History of Arabic Science, edited by Roshdi Rashed, pp. 128–184. London: Routledge. (See “The Earliest Table for Timekeeping,” pp. 173–176.)

——— (1997). “Astronomy in the Islamic World.” In Encyclopedia of the History of Science, Technology, and Medicine in Non‐Western Cultures, edited by Helaine Selin, pp. 125–134. Dordrecht: Kluwer Academic Publishers, pp. 130–131.

Sayılı, Aydın (1960). The Observatory in Islam. Ankara: Turkish Historical Society, pp. 101–103.

Suter, H. (1981). Die Mathematiker und Astronomen der Araber und ihre Werke. Amsterdam: APA‐Oriental Press, pp. 49–50 (no. 99).