| From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 727-728 |
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Majrīṭī: Abū al‐Qāsim Maslama ibn Aḥmad al‐Ḥāsib al‐Faraḍī
al‐Majrīṭī
Josep Casulleras
Born Madrid, (Spain),
first half of the 10th century
Died Cordova, al‐Andalus,
(Spain), 1007
Maslama
al‐Majrīṭī
was considered by his Andalusian contemporaries as the foremost authority
of his time in the field of astronomy. He traveled as a young man to Cordova,
the capital of the Umayyad caliphate, where he studied and worked until his
death. His achievements are mainly in the field of mathematical astronomy,
although it is known that he wrote on commercial arithmetic (muʿāmalāt) and was also a renowned
astrologer. Historians have at times misattributed to Majrīṭī
works on magic and alchemy.
In addition to his own compositions, Majrīṭī's importance lies within the context of Andalusian
science and his activity in scientific teaching. Majrīṭī
was the founder of an original school of Andalusian astronomers in which the
disciplines of arithmetic and geometry were also cultivated. Majrīṭī's disciples, who include outstanding figures like
Ibn al‐Samḥ,
Ibn al‐Ṣaffār, and Ibn Bargūth
(died: 1052), spanned three generations and greatly influenced the development
and expansion of the exact sciences throughout al‐Andalus. Majrīṭī
brought together for the first time in al‐Andalus two distinct mathematical
traditions, namely the tradition of farāʾīḍ (religiously based division of inheritances) and the
tradition of mathematically based philosophical sciences, a category that
included astronomy. Majrīṭī's combining of these two mathematical branches reflects
the interests of his two known teachers: ʿAbd al‐Ghāfir
ibn Muḥammad al‐Faraḍī, who wrote a treatise
on farāʾīḍ, and ʿAlī ibn Muḥammad
ibn Abī ʿĪsā al‐Anṣārī,
who is reported to have known astronomy.
In the field of astronomy, Majrīṭī
was the first Andalusian to make his own astronomical observations. According
to Zarqalī, he observed the star
Regulus in the year 979 and found its ecliptical longitude to be 135° 40'.
Starting from the determination of the longitude of this star, Majrīṭī
was then able to determine the longitude for all fixed stars, thereby establishing
a movement of precession of the equinoxes of 13° 10'
with respect to the epoch of compilation of the catalog of stars in Ptolemy's
Almagest.
The
above value for the longitude of Regulus appears in the table of stars that
accompanies Majrīṭī's commentary on Ptolemy's Planisphaerium,
which is a treatise on the stereographic projection of the sphere (the basic
technique for the construction of the standard astrolabe). Some historians
mistakenly thought that Majrīṭī
may have learned Greek and translated the Planisphaerium himself, but
recent investigation has shown that he most likely revised an eastern Arabic
translation of the work. Indeed, Majrīṭī's text contains several
additions to the work of Ptolemy that considerably improved the procedures
for tracing the fundamental lines of the astrolabe and for locating the fixed
stars of its rete, or star map on the instrument, using several kinds of coordinates.
In the second part of this work, Majrīṭī
deals with a number of problems of spherical astronomy using the Theorem of
Menelaus, which was the unique trigonometric tool employed in his time and
upon which he had previously written several notes in another work.
Majrīṭī's
major work in astronomy was the adaptation that he made, together with his
disciple Ibn al‐Ṣaffār, of Khwārizmī's
Sindhind zīj. This 9th century astronomical handbook with tables
and explanatory text was based primarily on Indian methods, and thus differed
from later Islamic astronomical material, which relied on planetary models
laid out in the Almagest. Although Khwārizmī's original text
appears to be lost, a Latin version by Adelard
of Bath (12th century) of Majrīṭī's revision is extant.
This text, which is referred to as the zīj of Khwārizmī‐Maslama
(Majrīṭī),
contains tables derived from Khwārizmī's original zīj
(which had material based upon Persian and Ptolemaic traditions in addition
to Indian ones) as well as material and tables that were adaptations, additions,
or replacements introduced by Majrīṭī and Ibn al‐Ṣaffār. The aim of the Andalusian
astronomers was to adapt the original tables to the time and place in which
they were living. For example, the Persian solar calendar used in Khwārizmī's
tables was replaced by the Muslim lunar calendar, and some tables that were
observer‐specific were adapted to the geographical coordinates of Cordova.
Khwārizmī's mean motion tables were calculated for radix positions
corresponding to the meridian of Arīn (the center of the world in the
Indian systems). A significant outcome of using Cordova's longitude was that
Majrīṭī provides the earliest
evidence of an important correction to the size of the Mediterranean Sea to
its actual size; this was preserved in most Andalusian geographical tables.
On the whole, the transformations affected the tables for chronology, mean
motions, mean conjunctions and oppositions, and visibility of the lunar crescent.
They also involved the addition of new tables related to the astrological
practices of equating the houses and projecting the rays. Moreover, the contents
of the final version of the zīj suggest the redactors included
some elements that, though not strictly necessary, were in use in contemporary
Andalusia. This is the case of the two trigonometric tables that are extant
in the Latin translation, one for the sine (based on a radius of 60 parts)
and the other for the cotangent (shadow length), which presumably were not
used in the original Sindhind. Other Andalusian contributions found
in the zīj are the reference to the Hispanic era (38 BCE) in the
chronological part, the use of the meridian and latitude of Cordova for certain
tables, and improved calculation methods that were both accurate and easier
to use.
As a professional
astrologer, Majrīṭī was also interested in the conjunction of Saturn
and Jupiter, which took place in 1006/1007; with it he foretold a change of
dynasty, ruin, slaughter, and famine.
Selected References
Balty‐Guesdon, Marie Genevievè (1992). “Médecins et
hommes de sciences en Espagne musulmane (IIe/VIIIe‐Ve/XIe s.).” Ph.D.
diss., Université de la Sorbonne Nouvelle – Paris III.
Comes, Mercè (1994). “The ‘Meridian of Water' in the Tables
of Geographical Coordinates of al‐Andalus and North Africa.” Journal
for the History of Arabic Science 10: 41–51. (Reprinted in The Formation
of al‐Andalus, Part 2: Language, Religion, Culture and the Sciences,
edited by Maribel Fierro and Julio Samsó, pp. 381–391. Aldershot: Ashgate,
1998.)
——— (2000). “Islamic
Geographical, Coordinates: al‐Andalus' Contribution to the Correct Measurement
of the Size of the Mediterranean.” In Science in Islamic Civilisation:
Proceedings of the International Symposium “Science Institutions in Islamic
Civilisation” and “Science and Technology in the Turkish and Islamic World,”
edited by Ekmeleddin Ihsanoğlu and Feza Günergun, pp. 123–138. Istanbul:
IRCICA.
Dalen,
Benno van (1996). “al‐Khwārizmī's Astronomical Tables Revisited:
Analysis of the Equation of Time.” In From Baghdad to Barcelona: Essays
on the History of the Islamic Exact Sciences in Honour of Prof. Juan Vernet,
edited by Josep Casulleras and Julio Samsó, Vol. 1, pp. 195–252. Barcelona: Instituto
“Millás Vallicrosa” de Historia de la Ciencia árabe.
Fierro, Maribel (1986). “Bātinism in al‐Andalus.
Maslama b. Qāsim al‐Qurṭubī (d. 353/964), Author of
the Rutbat al‐Ḥakīm and the Ghāyat al‐Ḥakīm
(Picatrix).” Studia Islamica 63: 87–112.
Hogendijk, Jan P. (1989). “The Mathematical Structure of Two
Islamic Astrological Tables for ‘Casting the Rays.'” Centaurus 32:
171–202.
Kunitzsch, Paul and Richard Lorch (1994). Maslama's Notes
on Ptolemy's Planisphaerium and Related Texts. Munich: Bayerischen
Akademie der Wissenschaften.
Samsó,
Julio (1992). Las ciencias de los antiguos en al‐Andalus. Madrid:
Mapfre, pp. 80–110.
Vernet,
Juan and María Asunción Catalá (1965). “Las obras matemáticas de Maslama de Madrid.”
Al‐Andalus 30: 15–45. (English translation in The
Formation of al‐Andalus, Part 2: Language, Religion, Culture and the
Sciences, edited by Maribel Fierro and Julio Samsó, pp. 359–379. Aldershot:
Ashgate, 1998.)