From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 559-560 |
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Ibn al‐Kammād:
Abū Jaʿfar Aḥmad ibn Yūsuf ibn al‐Kammād
Mercè Comes
Flourished al‐Andalus
(Spain), beginning of the 12th century
Ibn
al‐Kammād was a well‐known astronomer from al‐Andalus
who influenced a number of later astronomers' writing in the Arabic, Hebrew,
and Latin astronomical traditions. There is, however, little information about
his life. He was probably born in Seville although he spent his working life
in Cordova. Ibn al‐Kammād was a direct or indirect disciple of
Zarqālī (11th century). Later
astronomers from al‐Andalus, North Africa, and the Iberian Peninsula
refer to him, and references to him occur in Arabic, Latin, and Hebrew sources.
He seems to have also been known in eastern Islamic countries. The reference
to a horoscope cast by Ibn al‐Kammād in Cordova in 1116–1117 that
appears in the extant version of Ibn Isḥāq
al‐Tūnisī's
zīj suggests that he flourished at the beginning of the 12th century.
Some modern sources, from the 19th century onward, suggest that he died in
1195; however, in light of the aforementioned horoscope, this date should
be reconsidered.
Ibn
al‐Kammād wrote three zījes (astronomical handbooks
with tables): al‐Kawr ʿalā
al‐dawr,
al‐Amad ʿalā
al‐abad,
and al‐Muqtabas, which is a compilation of the two previous zījes.
None survives in a complete version of the original Arabic. What has survived
is the Latin translation of al‐Muqtabas made by John of Dumpno
in 1260 in Palermo (Biblioteca Nacional de Madrid, MS 10023). The same manuscript
contains several chapters that do not belong to al‐Muqtabas;
some of them are probably related to al‐Kawr. They too were translated
by John of Dumpno in 1262 in Palermo. Furthermore, there are also some tables
that do not belong to al‐Muqtabas in the last folios of the manuscript,
two of which are related to the city of Sale (Morocco). Some fragments of
al‐Kawr and Chapter 28 of al‐Muqtabas are preserved
in Arabic (Escorial MS 939 and Alger MS 1454).
A Castilian translation of a chapter on trepidation by Ibn al‐Kammād
is preserved in the Cathedral of Segovia Library (MS 115). This may belong
to one of his zījes, though there are no instructions on the use
of the tables as would be expected in the canons of a zīj. The
manuscript also contains some Alfonsine texts. In the chapter entitled Libro
sobre çircunferencia de moto sacado por tiempo seculo, which seems to
be a translation of al‐Kawr ʿalā
al‐dawr
(The periodic rotations) and/or al‐Amad ʿalā al‐abad
(For the span of eternity), Ibn al‐Kammād makes an error with respect
to Zarqālī's trepidation model. He assumes that the motion of the
pole of the ecliptic around its polar epicycle is equal to the motion of the
Head of Aries around its equatorial epicycle. An explanation showing the same
error and attributed to “some astronomers” is found in Naṣīr
al‐Dīn al‐Ṭūsī's Tadhkira. Another
Arabic text by Ibn al‐Kammād is preserved in the Iraq Museum of
Baghdad (MS 296 [782]), though it has not been studied to date.
Ibn
al‐Kammād also wrote an astrological treatise, the Kitāb
Mafātīḥ al‐asrār, of
which only Chapters 10–15 are extant. These chapters (kalām fī
al‐naymūdār li‐taṣḥīḥ ṭawāli ʿal‐mawālid), on astrological obstetrics,
explain how to use astronomical measurements to determine the duration of
a pregnancy. They are related to al‐Kawr and to some of the tables
accompanying, but not belonging to, al‐Muqtabas.
Ibn
al‐Kammād was strongly criticized by Ibn
al‐Hāʾim al‐Ishbīlī in the latter's
al‐Zīj al‐kāmil (circa 1205); Ibn al‐Hāʾim
notes as many as 25 errors in Ibn al‐Kammād's work, especially
in al‐Kawr ʿalā al‐dawr
and al‐Amad ʿalā
al‐abad.
These have mainly to do with solar and lunar motions, trepidation models,
trigonometry, timekeeping, and astrology. However, Ibn al‐Kammād's
influence is to be seen in a number of later astronomers writing in Arabic,
Hebrew, and Latin, such as Abū al‐Ḥasan
al‐Marrākushī (in the 13th century), Juan Gil,
al‐Ḥadib, Joseph ibn Waqār, and, in particular,
Jacob Corsuno, the author of the Tables of Barcelona dedicated to King
Peter the Ceremonious in the 14th century.
Calvo, Emilia (2002). “Ibn al‐Kammād's Astronomical Work in Ibn
al‐Hāʾim's al‐Zīj al‐kāmil fī‐ʾl‐taʿālīm: I. Solar Year,
Trepidation, and Timekeeping.” In Science and Technology in the
Islamic World, edited by S. M. Razaullah Ansari, pp. 109–120. Proceedings of the XXth
International Congress on History of Science (Liège,
20–26 July 1997), Vol. 21. Turnhout: Brepols.
Comes, Mercè
(1991). “Deux Échos Andalous à Ibn al‐Bannāʾ de Marrākush.”
In Le Patrimoine Andalous dans la Culture Arabe et Espagnole, pp. 81–94.
Tunis: Université
de Tunis.
——— (1996). “The Accession and Recession
Theory in al‐Andalus and the North of Africa.”
In From Baghdad to Barcelona: Studies in the Islamic Exact Sciences in
Honour of Prof. Juan Vernet, edited by Josep Casulleras and Julio Samsó, Vol. 1, pp. 349–364. Barcelona: Instituto “Millás Vallicrosa” de Historia de la Ciencia árabe.
——— (2001). “Ibn
al‐Hāʾim's Trepidation Model.” Suhayl 2: 291–408.
——— (2004).
“Ibn al‐Kammād.” In Enciclopedia de la Cultura Andalusí. Biblioteca de al‐Andalus. Fundación Ifn Tufaye
Vol. 3, pp. 732–734 (no. 724). Almería.
Chabás,
José and Bernard R. Goldstein (1994). “Andalusian Astronomy: al‐Zīj
al‐Muqtabis of Ibn
al‐Kammād.” Archive for History of
Exact Sciences 48: 1–41.
Goldstein, Bernard
R. and José Chabás (1996). “Ibn al‐Kammād's Star
List.” Centaurus 38: 317–334.
Mancha, J.
L. (1998). “On Ibn al‐Kammād's
Table for Trepidation.” Archive for History of Exact Sciences 52: 1–11.
Millás Vallicrosa,
José María (1942). Las traducciones orientales en los manuscritos de la
Biblioteca Catedral de Toledo. Madrid: Consejo Superior de Investigationes
Científicas, pp. 231–247.
——— (1949).
Estudios sobre historia de la ciencia española. Barcelona:
Consejo Superior de Investigationes
Científicas, p. 132.
Vernet, J.
(1979). “Un tractat d'obstetrícia astrològica.” In Estudios sobre historia
de la ciencia medieval, edited by José María Millás Vallicrosa, Barcelona:
Consejo Superior de Investigationes Científicas. pp. 273–300.