| From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, p. 475 |
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Courtesy of 
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Hāshimī: ʿAlī ibn Sulaymān al‐Hāshimī
Ṃnica Rius
Flourished 890
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 Ṭāriq, the Zīj al‐Sindhind
of Khwārizmī, the Mumtaḥan
zīj of Yaḥyā ibn Abī al‐Manṣūr,
the two zījes of Ḥabash, 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.