From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 561-562 |
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Ibn al‐Majdī: Shihāb al‐Dīn
Abū al‐ʿAbbās
Aḥmad ibn Rajab ibn
Ṭaybughā
al‐Majdī al‐Shāfiʿī
François Charette
Died Cairo (Egypt),
27/28 January 1447
Ibn
al‐Majdī was one of the major Egyptian astronomers during the first
half of the 15th century. He occupied the positions of muwaqqit (timekeeper)
at al‐Azhar Mosque and of “head of the teachers” at the Jānibakiyya
madrasa (privately endowed religious college).
Ibn
al‐Majdī received a traditional religious education in the fields
of Quranic studies, the prophetic traditions (ḥadīth), jurisprudence (fiqh),
and Arabic grammar and philology. He also became an expert in arithmetic,
geometry, the algebra of inheritance, theoretical astronomy (hayʾa),
and applied astronomy (mīqāt, literally, the science of timekeeping).
He learned the latter discipline under Jamāl al‐Dīn al‐Māridīnī,
who had been a student of the celebrated astronomer of Damascus, Ibn
al‐Shāṭir.
Later, Ibn al‐Majdī himself became a highly regarded teacher in
most of the above‐mentioned traditional disciplines as well as in the
mathematical sciences. Virtually all of his younger contemporaries and immediate
successors who were active in astronomy in Cairo were his pupils at one time
or another. A prolific and competent writer, Ibn al‐Majdī played
an important role as a didactic author; his writings were still read and commented
upon in Egypt in the late 19th century.
Ibn
al‐Majdī's numerous astronomical treatises deal with a wide range
of topics. Several of them are devoted to the compilation of annual ephemerides
but have yet to be carefully studied, notably his important treatise Jāmiʿ al‐mufīd fī bayān uṣūl
al‐taqwīm wa‐ʾl‐mawālīd (which also deals with
arithmetic, chronology, and astrology) and his Ghunyat al‐fahīm
wa‐ʾl‐ṭarīq ilā ḥall al‐taqwīm. However, his important set of auxiliary tables for
facilitating the calculation of planetary positions, entitled al‐Durr
al‐yatīm fī tashīl ṣināʿat al‐taqwīm, has been investigated
by E. S. Kennedy and D. King. These tables contain numerical entries for the
Sun, Moon, and planets and make a clever use of periodic relations very similar
to those that are at the core of Babylonian astronomy combined with an intelligent
application of the methods and parameters of Ptolemaic zījes (astronomical
handbooks). An anonymous set of such auxiliary tables based on the same principle
is known from 11th‐century Iran, so we are witnessing an older tradition
that reappeared in Cairo, circa 1400. Ibn al‐Majdī's auxiliary
tables, supplemented by his contemporaries and successors, were extremely
popular in Egypt up to the 19th century and inspired other, more extensive
sets of tables based on the same methods and on the newer parameters of the
zīj of Ulugh Beg.
Ibn
al‐Majdī's activities dealt intensively with astronomical instruments.
He composed numerous works, often didactical in character, dealing with the
astrolabe, the theory of stereographic projection, the use of the standard
astrolabic and sine quadrants as well as several unusual varieties of quadrants
(most of which had been invented by his 14th‐century predecessors),
and works on sundial theory. Among his writings we also find treatises on
the determination of the lunar crescent visibility, a topic of prime importance
to Muslim religious practice since the Islamic calendar is lunar. Ibn al‐Majdī
also dealt with the applied problems of finding the qibla (the holy
direction toward Mecca) and the orientation of roof ventilators.
Ibn
al‐Majdī's contributions to arithmetic and algebra deserve further
investigation. His treatise on sexagesimal arithmetic, a topic of fundamental
importance for astronomers, was praised by his former pupil Sibṭ al‐Māridīnī as being the only
satisfactory treatment of the subject known to him.
As a rule,
astronomers during the Mamluk period in Egypt and Syria (1250–1517) did not
engage in astrology because of their associations with religious institutions
— either as muwaqqits in mosques or as teachers in madrasas
or Sufi convents. Ibn al‐Majdī was something of an exception: A
noted religious scholar, he nevertheless treated the topic of mathematical
astrology in his al‐Jāmiʿ al‐mufīd and even cast a horoscope for a Mamluk amīr.
Brockelmann,
Carl Geschichte der arabischen Litteratur. 2nd ed. Vol. 2 (1949): 158–159;
Suppl. 2 (1938): 158–159. Leiden: E. J. Brill.
King, David A. (1974). “A Double‐Argument Table for the
Lunar Equation Attributed to Ibn Yūnus.” Centaurus 18: 129–146,
esp. 131, 133, 141–142. (Reprinted in King, Islamic Mathematical Astronomy,
V. London: Variorum Reprints, 1986; 2nd rev. ed., Aldershot: Variorum, 1993.)
——— (1986). A Survey
of the Scientific Manuscripts in the Egyptian National Library. Winona
Lake, Indiana: Eisenbrauns, no. C62.
King
David, A. and E. S. Kennedy (1980). “Ibn al‐Majdī's
Tables for Calculating Ephemerides.” Journal for the History of Arabic
Science 4: 48–68. (Reprinted in King, Islamic Mathematical Astronomy,
VI. London: Variorum Reprints, 1986; 2nd rev. ed., Aldershot: Variorum, 1993.)
al‐Sakhāwī, Shams al‐Dīn Muḥammad
(1934–1936). Al‐Dawʾ al‐lāmiʿ fī aʿyān
al‐qarn al‐tāsiʿ. 12 vols.
Cairo, vol. 1, pp. 300–302.
Suter,
Heinrich (1900) “Mathematiker und Astronomen der Araber und ihre Werke.” Abhandlungen zur
Geschichte der mathematischen Wissenschaften 10: 175–177; and Suter, “Nachträge
und Berichtigungen,” Abhandlungen zur Geschichte der mathematischen Wissenschaften
14 (1902): 178. (Both reprinted in Suter, Beiträge zur Geschichte der Astronomie
im Islam, edited by Fuat Sezgin. 2 vols. Frankfurt, 1986, vol. 1, pp.
1–285 and 286–314.)