Abd-al-Rahman Al Sufi (December 7, 903 - May 25, 986 A.D.)
Abd-al-Rahman Al Sufi (or Abr-ar Rahman As Sufi, or - according to
R.H. Allen (1899) - Abd al Rahman Abu al Husain,
sometimes referred to as Azophi) was living at the court of the Emire Adud
ad-Daula in Isfahan (Persia), and working on astronomical studies based on
Greek work, especially the Almagest of Ptolemy.
He contributed several corrections to Ptolemy's star list, in particular he
did own brightness/magnitude estimates which frequently deviated from those
in Ptolemy's work.
Also, he was the first to attempt to relate the Greek with the traditional
arabic star names and constellations, which was difficult as these
constellations were completely unrelated and overlapped in a complicated way.
Al Sufi published his famous "Book of Fixed Stars" in 964
(Al Sufi, 964), describing much of his work, both in
textual descriptions and pictures. In his descriptions and
pictures of Andromeda, he included
"A Little Cloud" which is
actually the Andromeda Galaxy M31.
He mentions it as lying before the mouth of a Big Fish, an Arabic
constellation. This "cloud" was apparently commonly known to the Isfahan
astronomers, very probably before 905 AD.
In this book, he probably also cataloged
the Omicron Velorum cluster IC 2391 as a
"nebulous star", and an additional "nebulous object" in Vulpecula, a cluster
or asterism now known as Al Sufi's or Brocchi's
Cluster, or Collinder 399.
Moreover, he mentions the Large Magellanic Cloud
as Al Bakr, the White Ox, of the southern Arabs as it is invisible from
Northern Arabia because of its southern latitude.
Al Sufi's observations were not known in Europe at the time of the invention
of the telescope, so that the Andromeda Nebula M31 was independently
rediscovered by Simon Marius in 1612 with a moderate
The astronomical community has honored Al Sufi by naming a Moon Crater after
him; Moon Crater Azophi is at 22.1S, 12.7E and 47.0 km in diameter.
Nebulous Objects in Al Sufi's
Book of the Fixed Stars
Schjellerup (1874) identifies No. 6 as
"4 and 5 Vul," No. 7 as the Andromeda "Nebula," and assumes No. 8 is John
Herschel's h 3140 (NGC 2669), which however is non-existent; IC 2391 was not
recognized at that time (1874).
- 1. [h and Chi Per (NGC 869/884),
Ptolemy No. 191]
"The first star [in Perseus] is the little cloud .. situated on the right
- 2. [M44 (Praesepe, NGC 2632),
Ptolemy No. 444]
"The first of the stars [in Cancer] is the little patch which resembles a
small cloud surrounded by four stars which are found - with the patch being
in the middle - two in fromt and two behind."
- 3. [M7 (NGC 6475), Ptolemy No. 567]
"The first of the stars external to the figure [of Scorpius] is the
nebulosity following the sting; mag 4-5."
- 4. [Ptolemy No. 577, asterism of Nu1 and Nu2 Sgr]
"The eighth star of Sagittarius is the cloudy star, which is also double,
in the eye."
- 5. [Ptolemy No. 734, asterism of Lambda, Phi1 and Phi2 Ori]
"The first star of the Giant [Orion] is the cloud which is in the head and
which is composed of three stars."
- 6. [Cr 399, including 4 and 5 Vul]
".. a little cloud situated to the north of two stars in the notch of
- 7. [M31 (Andromeda Galaxy, NGC 224)]
"The Arabs recognize two series of stars surrounding the figure of a large
Fish below the throat of the Camel. These stars belong partly to this
constellation [Andromeda] and partly to the northern Fish which Ptolemy
describes as the twelfth figure of the Zodiac.
These two series begin at a little Cloud situated very close to the 14th star
which is found at the right side [of And] and which belongs to the three
which are above the girdle."
- 8. [IC 2391 (Omicron Velorum Cluster)]
".. above the 37th star [Delta Navis], at a distance of one cubit, there is
a nebulous star."
- Richard Hinckley Allen, 1899.
Star-Names and their Meanings. G.E. Stechert. Reprinted as:
Star Names, their Lore and Meaning. Dover Publications, New York, 1963.
- Abd-al-Rahman Al Sufi, 964.
Book of Fixed Stars. Isfahan, Persia.
For a French translation, see
- Kenneth Glyn Jones, 1968.
The Search for the Nebulae -- I.
Journal of the British Astronomical Association, Vol. 78, No. 4 (1968),
p. 256-267. Section on Al Sufi: p. 263-266.
Reprinted in: The Search for the Nebulae. Chalfont St. Giles, 1975.
- H.C.F.C. Schjellerup, 1874.
Descriptions des Étoiles Fixes, composée au Milieu du
Dixième Siècle de Notre Ère,, par l'astronome Persan,
Abd-al-Rachman al-Sûfi. St. Petersburg.
- Gotthard Strohmaier, 1984.
Die Sterne des Abd ar-Rahman as-Sufi.
Verlag Müller & Kiepenheuer, Hanau/Main (Germany).
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