From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, p. 475

Courtesy of

Hāshimī: ʿAlī ibn Sulaymān al‐Hāshimī

Ṃnica Rius


Hāshimī's only known astronomical work is his Kitāb fī ʿilal al‐zījāt (Book of the reasons behind astronomical tables); although it does not contain innovative ideas, it does provide a great deal of extremely useful information for the history of science and preserves materials from the Hellenistic world, India, and the Sasanians that would otherwise be lost. The unique 13th‐century manuscript does not indicate the date of its original composition; however, it may date from the late 9th century since the treatise is mentioned by several authors from the 9th century, but none from the 10th.

The book is divided into sections on various aspects of astronomy. The first section is on zījes (astronomical handbooks), and Hāshimī explains the meaning of a zīj, as well as provides a historical introduction with commentaries to various zījes. These include Ptolemy's Almagest, Theon's Canon, the Arjabhar, the Zīj al‐Arkand, the Zīj al‐jāmiʿ, the Zīj al‐Hazūr, the Zīj al‐Shāh of Khusro Anūshirwān, the Zīj al‐Shāh of Yazdigird III, Fazārī's Zīj al‐Sindhind, the Zīj of Yaʿqūb ibn āriq, the Zīj al‐Sindhind of Khwārizmī, the Mumtaan zīj of Yayā ibn Abī al‐Manūr, the two zījes of abash, and the (Thousands) Zīj al‐hazārāt of Abū Maʿshar.

The ʿIlal also includes sections on chronologies and calendars; cycles and world‐days; operations based on the cycles; equations, kardajas, and sectors; the solar motion and related problems; lunar tables and equations; and miscellaneous subjects such as the lengths of night and day and equation of time, rising and setting amplitudes in the various climates, time of sunrise as affected by the Sun's declination, projection of the rays, and lunar and solar eclipses.

Hāshimī's ʿIlal al‐zījāt provides us with a valuable indication of astronomy during this period as well as Hāshimī's understanding of certain astronomical texts. It is clear that this work is written at a time before the ascendancy of Greek astronomy in the Islamic world, when Indian and Sasanian astronomy were still on an equal footing with it.

Hāshimī also contributed to the development of mathematics, specifically calculation with irrational quantities.

Selected References

al‐Hāshimī, ʿAlī ibn Sulaymān (1981). The Book of the Reasons behind Astronomical Tables (Kitāb fī ʿilal al‐zījāt). A facsimile reproduction of the unique Arabic text contained in the Bodleian MS Arch. Seld. A.11 with a translation by Fuad I. Haddad and E. S. Kennedy and a commentary by David Pingree and E. S. Kennedy. Delmar, New York: Scholars' Facsimiles and Reprints.

Sezgin, Fuat (1978). Geschichte der arabischen Schriftums. Vol. 6, Astronomie, p. 176. Leiden: E. J. Brill.