| From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 362-363 |
|
Courtesy of 
|
Fazārī: Muḥammad ibn Ibrāhīm al‐Fazārī
Kim Plofker
Born possibly (Iraq),
8th century
Died possibly Baghdad,
(Iraq), early 9th century
Fazārī
played a pivotal role in the initial development of the Arabic astronomical
tradition from Indian, Sasanian, and Greek sources, but almost nothing of
his own works remains with us. Not even his identity is entirely certain:
there was some ambiguity among medieval biographers as to whether “Ibrāhīm
ibn Ḥabīb
al‐Fazārī” and “Muḥammad ibn Ibrāhīm
ibn Ḥabīb
al‐Fazārī” were two different people, namely father and son.
It is now assumed, however, that the various references to the astronomer
Fazārī mean the same individual.
This individual
was apparently a descendant of an old family in Kūfa (near Najaf in modern
Iraq) and worked on astronomy and astrology – particularly the composition
of astronomical handbooks with tables for computing celestial positions (zījes)
– at the court of al‐Manṣūr (reigned: 754–775) and later ʿAbbāsid caliphs.
He helped supervise the casting of the horoscope that selected the auspicious
date for the founding of Baghdad in 762. In the early 770s, at the caliph's
request, he collaborated in the translation of a Sanskrit astronomical text
brought to Baghdad by an Indian astronomer. Fazārī based his Zīj
al‐Sindhind al‐kabīr (Great astronomical tables of the
Sindhind; from Sanskrit siddhānta, “system” or “treatise”) on
that work. Probably a decade or so later, he wrote another zīj
entitled Zīj ʿalā
sinī al‐ʿArab (Astronomical tables
according to years of the Arabs). Fazārī also composed – apparently
in imitation of the style of Sanskrit technical treatises in metrical verse
– a long poem on astronomy and/or astrology, Qaṣīda
fī ʿilm (or hayʾat)
al‐nujūm (Poem on the science [or configuration] of the
stars). Some scattered remarks on these works, with occasional citations from
them, are found in the works of later authors.
Also ascribed to Fazārī, but known only from their titles,
are Kitāb al‐Miqyās li‐ʾl‐zawāl
(Book on the measurement of noon), Kitāb al‐ʿAmal bi‐ʾl‐asṭurlāb
wa‐huwa dhāt al‐ḥalaq (Book on the use of the
armillary sphere), and Kitāb al‐ʿAmal
bi‐ʾl‐asṭurlāb
al‐musaṭṭaḥ (Book on the use of the
astrolabe). Fazārī was said to have been the first Muslim to construct
a plane astrolabe; indeed, according to several biographers, he was a pioneer
and positively unrivaled in his mastery of the astral sciences. The 11th‐century
astronomer Bīrūnī (from
whom comes most of our knowledge of details of Fazārī's astronomy)
is somewhat more critical, especially about probable mistakes of Fazārī
and his colleague Yaʿqūb ibn
Ṭāriq in interpreting the terms
or techniques of the Sanskrit astronomical work they translated.
Although,
as noted above, Fazārī based his first zīj primarily
upon this Sanskrit text (probably entitled Mahāsiddhānta
or Great Siddhānta), he seems to have added to it a good deal of material
from other sources. The Mahāsiddhānta apparently belonged
to the Indian astronomical tradition associated with the 7th‐century
Brāhmasphuṭasiddhānta of Brahmagupta,
but the features ascribed in the comments of later authors to the Zīj
al‐Sindhind al‐kabīr are an eclectic (and sometimes flatly
contradictory) mix, including parameters and procedures derived not only from
rival Indian schools, but also from the Sasanian Persian astronomical tradition,
with a little Ptolemaic influence as well.
Fazārī
is credited with the innovation of converting the Indian planetary longitude
computus involving billions of revolutions (suffering, as Hāshimī
remarked, from “the length of its operations in multiplication and division
and the tedious nature of the computations”) into ones using sexagesimal values
of mean motions. (In fact, Indian astronomers too had tabulated and used sexagesimal
mean motions.) His second zīj, according to its title and a surviving
table copied from it into later works, was designed to enable the user to
find the desired positions for dates in the Arabic calendar. Even these fragmentary
references suffice to show that Fazārī's contributions had a significant
impact on nascent Arabic astronomy, although his work as a whole did not withstand
competition from later (and presumably better‐organized) treatises.
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.
(The early zījes inspired by Indian sources are intermittently
discussed herein.)
Pingree, David (1970). “The Fragments of the Works of al‐Fazārī.”
Journal of Near Eastern Studies 29: 103–123. (The extant information
about Fazārī's writings are collected herein; few additional details
have come to light since.)
Sezgin,
Fuat (1978). Geschichte des arabischen Schrifttums. Vol. 6, Astronomie, pp. 122–124. Leiden: E. J. Brill.