Al Zarqali (Arzachel_(1029 - 1087 C.E.) Astronomy, Engineering
Astronomy (Invented Astrolabe)
- [astronomy,
engineering] Arzachel (al-Zarqali) invents the "Saphaea", the first
astrolabe that did not depend on the latitude of the observer and could be used
anywhere. He also invents the equatorium,and discovers that the orbits of the
planets are ellipses and not circles.
Saintis Barat mengenalnya dengan panggilan Arzachel. Wajah
Al-Zarqali diabadikan pada perangko di
Spanyol,
sebagai bentuk penghargaan atas sumbangannya terhadap
penciptaan astrolabe yang lebih baik. Beliau telah menciptakan jadwal Toledan
dan juga merupakan seorang ahli yang menciptakan astrolabe yang lebih kompleks
bernama Safiha.
Azarquiel
According to his biographer Isḥāq Israeli, Zarqālī was a renowned instrument maker in Toledo, where he taught himself astronomy. He worked for Ṣāʿid al‐Andalusī and was a leading figure among Ṣāʿid's group of astronomers. An anonymous Egyptian 14th‐century source (Kanz al‐yawāqīt, Leiden Universiteitsbibliotheek, MS 468) quotes a passage from Ṣāʿid's lost work entitled Ṭabaqāt al‐ḥukamāʾ, in which it is stated that Zarqālī constructed an astronomical instrument, called al‐zarqāla, for al‐Maʾmūn (1043–1075), the ruler of Toledo, in the year 1048/1049. It also says that Zarqālī wrote a treatise of 100 chapters on its use. Zarqālī left Toledo between 1081, the beginning of the reign of al‐Qādir, and 1085, the date of the conquest of the city by Alfonso VI. He settled in Córdova, where he was protected by al‐Muʿtamid ibn ʿAbbād (1069–1091), ruler of Seville.
There are many variations of the name of Zarqālī, known as Azarquiel in Latin. According to the Ṭabaqāt al‐umam of Ṣāʿid al‐Andalusī, he was known as walad al‐Zarqiyāl, from whence came the Hispanicized formAzarquiel. The 13‐century biographer al‐Qifṭī maintains the expression walad al‐Zarqiyāl in his Akhbār al‐ʿulamā” bi‐akhbār al‐ḥukamāʾ. Other readings quoted in Andalusian sources are al‐Zarqālluh, al‐Zarqāl, or Ibn Zarqāl; readings such al‐Zarqāla and al‐Zarqālī (sometimes al‐Zarqānī) seem to be classicized Eastern forms.
Background to Al-Zarqali's life
Before the agitated period corresponding to Al-Zarqali's life, Spain was the light in Europe. It had scientists of unique calibre, the likes of Ibn Firnas, for instance (d. 887), a poet, a mathematician, an astronomer and physicist at the Spanish Ummayad court under three successive rulers, who could decipher even the most incomprehensible hieroglyphics [1]. He also invented spectacles, complex chronometers, and a flying machine [2]. Al-Zahrawi, also known as Albucasis in Latin (936-1013), wrote on medicine, pharmacology, and also on cookery and dietetics, medical chemistry, therapeutics, and above all surgery. Abu Hanifa al-Dinawari (d. 895) left extensive works in botany; his works were brought to us by the German scholar Silberberg [3]. Al-Majriti (d. 1007) was an astronomer, a chemist, and he also wrote treatises on commercial arithmetic and on taxes, using algebraic, geometrical, and arithmetical operations.
Cordova, the capital of Muslim Spain, used to be the jewel of Europe which dazzled visitors from the North [4]. It was "the most civilised city in Europe, the wonder and admiration of the world, a Vienna among Balkan states [5]." Its streets were paved and well lit [6]. One could travel for ten miles by the light of street lamps, and along an uninterrupted series of buildings [7]. It also had around 70 public libraries during the time of Caliph Hakam II, and 900 public baths [8]. Included amongst its libraries were the great mosque libraries which were open for anyone to go and use. And whenever the rulers of Leon, Navarre or Barcelona needed a surgeon, an architect, or a dress maker, they applied to Cordova [9].
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Figure 1: View of Toledo, the city of Al-Zarqali, dominated by the famous Alcazar (Source).
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This brilliance was pursued under al-Mansur (also known as Ibn abi Amir), who ruled on behalf of the young prince Hisham, from 976 to 1002. Al-Mansur kept the northern Christians under check, mounting two military campaigns every year against them. At home, Al-Mansur extended the great mosque of Cordoba, and built the magnificent al-Zahra City. Under him, Spain was also at the peak of its wealth, visitors stunned by the mountains of riches.
Soon after the death of the great leader al-Mansur, Muslim Spain fell into chaos, the era of the "party kings"(reyes de taifas, muluk at-tawa'if) (1009-1091), when the Peninsula broke into as many as thirty more or less independent rulers, who fought each other [10]. Encouraged by this, Christian princes in North West Spain swept south, conquering one Islamic kingdom after the other, very often using one against the other [11]. Barbastro was taken in 1063 from the Muslims [12]. In 1085, the old Visigoth capital of Toledo fell to Alfonso VI of Castile [13], a victory achieved with the help of al-Mutamid of Seville [14]. Al-Mu'tamid, himself, was soon threatened [15]. In panic, with other kings, he called the Almoravids, and their leader Yusuf Ibn Tashfin, to protect them from the invasion of the Castillan troops. Ibn Tashfin crossed into Spain on three occasions, each time after crushing the Christian armies, he was invited to leave. The third time he was invited in 1090, Ibn Tashfin crossed the straight of Gilbraltar, and this time eliminated the Reyes de taifas, and installed Almoravid rule all over the country [16]. The Almoravids, followed by the Almohads kept Andalusia in Muslim hands until the 13th century. But disunity and infighting led this time to a final disintegration. Cordova fell in 1236, Seville in 1248, and soon followed the other towns and cities, only leaving the Grenada enclave which fell later in 1492.
To understand what the fall of such Muslim towns and cities, and the fall of Islamic power meant for Muslim scholarship, nothing better than the life of Al-Zarqali, who lived in the first period of chaos when the Castillans attacked the disunited Reyes of Taifas, before the Almoravid intervention stopped the upcoming invasion. Like other Muslim scholars who lived during this chaotic period, each time, fleeing from one place to another as the Christians advanced; Al-Zarqali, for instance, fled Toledo his hometown when it was threatened by the Castillans, before it fell in 1085. Many of the leading Muslim Spanish scholars and men of letters, lived through the same experience. Ibn Bassam describes how the incessant invasions of the Castillans forced him to run away from Santarem in Portugal, "the last of the cities of the west," after seeing his lands ravaged and his wealth destroyed, a ruined man with no possessions save his battered sword [17]. Many scholars such as Abu Salt of Denia, and Abu Behr al-Tortuchi of Tortosa left Spain altogether to take refuge in Egypt [18]. Others were still more unfortunate, like the poet Ibn Wahbun, who was killed by the Castillans on the road from Lorca to Murcia in 1087 [19].
Al-Zarqali's life and achievements
Al-Zarqali, Barron Carra de Vaux tells us, was given the surname ‘Al-Nekkach', that is the engraver of metals[20]. According to established tradition, he was a mechanic and metal craftsman, very crafty with his hands[21]. It is as an instrument maker that al-Zarqali entered the services of Cadi Ibn Said of Toledo. He would make delicate instruments needed to continue astronomical observations that begun in 1060, possibly begun by Yahya Ibn Abi Mansur [22]. First Al-Zarqali built instruments for other scholars, but when they realised his great intellect, they became interested in him. As he told them he was man of little learning, having never studied any science, nor even touched a book, they put him to task, and made him study and learn [23]. They put at his disposal books he needed to educate himself [24]. And two years later, in 1062, he became a member of the group, and soon after the director of this very group [25]. Al-Zarqali kept on making instruments for others which they asked for, but now began to invent his own, and even sooner, he began to teach his own masters, to the point, that they soon began to follow him, and calculate exactly as he did [26].
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Figure 2: Spanish stamp of Al-Zarqali with astrolabe.
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Al-Zarqali constructed the famed clocks of Toledo, which al-Zuhri has described in a Castilian translation, published by J.M. Millas-Vallicrosa [27]. The clocks were in use until 1135, when King Alphonso VI tried to discover how they worked and asked Hamis Ibn Zabara to dismantle them [28]. Once they were taken apart, nobody could reassemble them. They constituted a very precise lunar calendar and were, to some extent, the predecessors of the clocks or planetary calendar devices that became fashionable six centuries later in Europe [29].
Ahmad Thomson has given a vivid account of the intricate working of the clocks. The clocks consisted of two basins, which filled with water or emptied according to the increasing or waning of the moon. At the moment when the new moon appeared on the horizon, water would begin to flow into the basins by means of subterranean pipes, so that there would be at day-break the fourth of a seventh part, and at the end of the day half a seventh part, of the water required to fill the basins. In this proportion the water would continue to flow until seven days and as many nights of the month had elapsed, by which time both basins would be half filled. The same process during the following seven days and nights would make the two basins quite full, at the same time that the moon was at its full. However, on the fifteenth night of the month, when the moon would begin to wane, the basins would also begin to lose every day and night half a seventh part of their water, until by the twenty-first of the month they would be half empty, and when the moon reached her twenty-ninth night not a drop of water would remain in them. It is worthy of remark that, should anyone go to any of the basins when they were not filled, and poured water into them with a view to quicken its filling, the basins would immediately absorb the additional water and retain no more than the just quantity; and, on the contrary, were anyone to try, when they were nearly filled, to extract any or the whole of their water, the moment he raised his hands from the work the basins would pour out sufficient water to fill the vacuum in an instant [30].
This was only one aspect of Al-Zarqali's achievements, for he constructed the most sophisticated and precise astrolabe ever. The astrolabe was a composite astronomical instrument which performed a variety of operations. The most common form, the planispheric astrolabe, had on its front a zodiacal circle and a disc (safîha or azafea, in medieval Castilian) designed for a specific geographical latitude, with a stereographic projection of the equator, the tropics, and the horizon [31]. Which made possible the solution of various problems of spherical astronomy, and to measure the hour of the day [32]. Al-Zarqali invented constructed and wrote al-Safiha al-Zarqaliya (Azafea), a treatise on the universal astrolabe; an instrument out of which a whole literature developed later [33]. It was a stereographic projection for the terrestrial equator and could be used to solve all the problems of spherical astronomy for any latitude [34]. It includes a table of 29 stars with ecliptical coordinates intended to be marked on the instrument [35]. The refined astrolabes were also used for observing the sun's movement [36]. This innovation, which avoided the inconvenience of having to change the safîha for each latitude. The universal plate impacted on subsequent Western science; as illustrated in the Alfonsine Libros de saber de astronomia, through which it became known in Europe, as did the armillary sphere [37].
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Figure 3: North African universal astrolabe (probably from the 13th century) at the Museum of the History of Science, University of Oxford (Inventory n° 41122). This astrolabe uses the ‘universal lamina' described by Al-Zarqali, where a special form of rete rotates above a horizontal projection of the entire celestial sphere (Source).
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A Jew from Montpellier in France translated it into Latin; King Alfonso of Castile made two translations of it into Romance (Spanish), whilst Regiomontanus in the 15th century published a collection of problems on the ‘noble instrument of the safiha' [38].
Al-Zarqali, most of all, is a genial astronomer, whose accomplishments are too many to tell here. Like other Muslim scholars he corrected the Greeks, which again, disproves the idea that Muslim science is a copy of the Greeks, for it both corrects such Greek science and adds discoveries which became the realm of the European West many centuries later. Ptolemy's exaggerated estimate of the length of the Mediterranean sea at 620 were first cut by al-Khwarizmi to 520, then by al-Zarqali to the near the correct value of 420[39]. Al-Zarqâli also wrote a treatise on the movement of the fixed stars, a discussion of theories regarding the solar year [40]. His astronomical observations were the best of his age, and enabled him to prove for the first time the motion of the solar apogee with reference to the stars [41]. Motion of the solar apogee with reference to the stars which he said amounted to 12.04' a year; and also gave a value of 770 50' for the longitude of the sun's apogee, and concluded that the inclination of the ecliptic oscillated between 23033' and 23053' [42].
In his Tratado relativo al-moviemento de las estrellas fijas, only preserved in a Hebrew copy, al-Zarqali sought to demonstrate mathematically the trepidation theory according to which the movement of the sphere of the fixed stars is determined by the movement of a straight line that joins the centre of the earth with a movable point on a base circle or epicycle [43]. Al-Zarqali explains the trepidation theory according to three models that situate the epicycle 1) in a meridian plane; 2) in the plane of the ecliptic, and 3) with two equal epicycles centred in the mean equinoctial points normal to the equator [44].
The construction of astronomical tables implied trigonometrical theories and computations which were generally explained in the introductory chapters to these tables. In Al-Zarqali can be found a section dealing with trigonometry, which includes tables of sines, cosines, versed sines, secants, and tangeants [45]. The work was translated into Latin by the Italian John of Pavia in 1154; William de St Cloud in 1296; a Hebrew version by Jacob Ibn Tibbon in 1301; and also translated into Portuguese, Catalan, Castilian, etc [46].
Al-Zarqali, however, is even more famed, and impacted for centuries on the Christian West with regard to hisToledan Tables [47]. The tables include the determination of the right ascensions, and the equations of the sun and the moon and of the planets; parallax; eclipses, and the setting of the planets; theory of trepidation or accession and recession; etc [48]. His work was translated into Latin by Gerard of Cremona, and was very popular for more than two centuries [49]. All subsequent tables for different locations in Europe were based on al-Zarqali's measurements. The tables of Marseilles (based on Al-Zarqali's Toledan Tables) were also adapted to the meridians of London, Paris and Pisa [50].
Raymond of Marseilles is one of the first who adapted Al-Zarqali's table to a European location, Marseilles[51]. Leopold of Austria, an Austrian astronomer and meteorologist, who flourished probably in the middle of the second half of the 13th century, composed an astronomical treatise which was professedly a compilation, entitled Compilatio de astronum scientia, divided into ten treatises, who also relied on al-Zarqali to great measure [52]. Alfonso the Wise's Tablas alfonsinas were also based on al-Zarqâli's work [53]. Robert of Chester's work was less a translation than an adaptation of the tables of al-Battani and al-Zarqali for the coordinates of London composed in 1149 [54].
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Figure 4: Diagram of the movement of the sun (ecliptic).
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Al-Zarqali, who was once given books at a late stage of his life to learn, later on had his own students such as the reputed Yahia Ibn Sayyid (d. 1144); and his influence was exerted upon some of the greatest astronomers of Islam, such as Ibn al-Kammad, Al-Bitruji, Abu' Hasan al-Murrakushi, Ibn al-Banna and others[55]. Just like Ibn Sina, al-Kindi, al-Farabi, Al-Razi, al-Farghani, and al-Khwarizmi, al-Zarqali was printed in Europe quite frequently, up to the sixteenth and even the 17th century [56].
Whilst Copernicus, for instance, relied profusely on al-Zarqali (and al-Battani) in his book De Revolutionibus[57], and on his treatise on the astrolabe [58], Abraham Zacut, whose solar declination tables were used by explorers of the 16th century to calculate latitudes, followed al-Zarqali on planetary and solar motion [59].
In his Jāmiʿ al‐mabādiʾ wa‐ʾl‐ghāyāt fī ʿilm al‐mīqāt, an encyclopedic work on astronomy, Abū al‐Ḥasan ʿAlī al‐Marrākushī (13th century) states that Zarqālī was making observations in Toledo in 1061. This testimony is confirmed by Ibn al‐Hāʾim al‐Ishbīlī (flourished: 1204/1205) in his al‐Zīj al‐kāmil fī al‐taʿālīm, who attributes to Zarqālī 25 years of solar observations and 37 years of observations of the Moon. Al‐Qifṭī says that his observations were used by Ibn al‐Kammād.
One can generally classify the contents of Zarqālī's work under four main categories: astronomical theory, astronomical tables, magic, and astronomical instruments.
The following four works by Zarqālī deal with astronomical theory: (1) There is a treatise on the motion of the fixed stars, written circa 1084/1085 and extant in Hebrew translation. It contains a study of three different trepidation models, in the third of which variable precession becomes independent of the oscillation of the obliquity of the ecliptic. (2) There is a lost work summarizing 25 years of solar observations, probably written circa1075–1080. Its contents are known through secondary sources, both Arabic and Latin. The title was either Fī sanat al‐shams (On the solar year) or al‐Risāla al‐jāmiʿa fī al‐shams (A comprehensive epistle on the Sun). In this work Zarqālī established that the solar apogee had its own motion (of about 1° in 279 Julian years) and devised a solar model with variable eccentricity that became influential both in the Maghrib and in Latin Europe until the time of Nicolaus Copernicus. (3) There is an indirect reference to a theoretical work entitled Maqāla fī ibṭāl al‐ṭarīq allatī salaka‐hā Baṭlīmūs fī istikhrāj al‐buʿd al‐abʿad li‐ʿUṭārid (On the invalidity of Ptolemy's method to obtain the apogee of Mercury) mentioned by Ibn Bājja. (4) There is a reference in Ibn al‐Hāʾim's work to Zarqālī's lost writing (bi‐khaṭṭ yadi‐hi, in his own hand) describing a correction to the Ptolemaic lunar model. Ibn al‐Hāʾim understands this correction as a result of the displacement of the center of the lunar mean motion in longitude to a point on a straight line linking the center of the Earth with the solar apogee, and at a distance of 24'. This model met with some success, for we find the same correction in later Andalusian (Ibn al‐Kammād) and Maghribī (Ibn Isḥāq, Ibn al‐Bannāʾ) zījes, although restricted to the calculation of eclipses and the New Moon. It appears also in the Spanish canons of the first version of the Alfonsine Tables and in a Provençal version of the tables of eclipses of Gersonides, although in these tables the amount is given as 29' (either a copying error or a new estimation).
There are two works by Zarqālī dealing with astronomical tables: (1) The Almanac is preserved in Arabic, Latin, and in an Alfonsine translation. It is based on a Greek work calculated by a certain Awmātiyūs in the 3rd or 4th century, although the solar tables seem to be the result of the Toledan observations. Its purpose is to simplify the computation of planetary longitudes using Babylonian planetary cycles (goal years). (2) The Toledan Tables are known through a Latin translation. They seem to be the result of an adaptation of the best available astronomical material (i. e., Khwārizmī and Battānī) to the coordinates of Toledo that was made by a team led by Ṣāʿid and in which Zarqālī seems to have been a prominent member. The mean‐motion tables are original and are the result of observations. Ṣāʿid does not mention these tables although they had been completed before the writing of the Ṭabaqāt in 1068.
The only known magical work by Zarqālī is entitled Risāla fī Ḥarakāt al‐kawākib al‐sayyāra wa‐tadbīri‐hi (On the motions and influences of planets), which is a treatise on talismanic magic using magic squares to make talismans. It is preserved in two Arabic manuscripts, which contain two different versions of the text. There is also a third one summarized in a Latin translation.
Finally, Zarqālī has several works on astronomical instruments: (1) There is a treatise on the construction of the armillary sphere, which is preserved in an Alfonsine–Castilian translation. The original Arabic has not survived. (2) There are two treatises on the construction (circa 1080/1081) and use (circa 1081/1082) of the equatorium, dedicated to al‐Muʿtamid. Zarqālī's equatorium differs from the earlier Andalusian model designed byIbn al‐Samḥ (circa 1025/1026) in that it is an independent instrument that represents all the planetary deferents and related circles on both sides of a single plate, while a second plate bears all the epicycles. Mercury's deferent is represented as an ellipse. (3) Marrākushī attributes to Zarqālī a sine quadrant with movable cursor (majarra), which is a graphic scale of solar declination with the solar longitude as argument. It is similar to the quadrant vetustissimus, although in this quadrant the argument used is the date of the Julian year. (4) There are two treatises on two variants of the same astronomical universal instrument (al‐ṣaf īḥa al‐mushtaraka li‐jamīʿal‐ʿurūḍ): A 100‐chapter treatise on the use of the ṣaf īḥa (plate), called the zarqāliyya, and another treatise of 60 chapters on the use of the ṣaf īḥa shakkāziyya. In both instruments the stereographic equatorial projection of the standard astrolabe is replaced by a stereographic meridian projection onto the plane of the solstitial colure. In fact, it is a dual projection corresponding to each of the Celestial Hemispheres, one of which had its viewpoint at the beginning of Aries and the other at the beginning of Libra. The end result was obtained by superimposing the projection from Aries (turning it) onto the projection from Libra. The two variants of the ṣaf īḥadiffer slightly. The zarqāliyya has, on its face, a double grid of equatorial and ecliptical coordinates and a ruler horizon representing the horizontal ones. On its back, in addition to the features proper to the astrolabe, it shows an orthographic meridian projection of the sphere, a trigonometric quadrant, and a small circle (named “of the Moon”) used to compute the geocentric distance of the Moon. The shakkāziyya is a simplification of thezarqāliyya, as Marrākushī states in his Jāmiʿ. On its front it bears a single grid of equatorial coordinates and a grid of ecliptical ones reduced to the ecliptic line and the circles of longitude marking the beginning of the zodiacal signs. The back of this kind of ṣaf īḥa is the same as the back of the astrolabe. There is an Alfonsine translation of the treatise on the zarqāliyya, as well as several translations into Latin and Hebrew of the treatise on the shakkāziyya.
Marrākushī was one of the major astronomers in 13th‐century Egypt. As his name indicates, he was
originally from Maghrib, but his major astronomical activities took place in Cairo during the second
half of the 13th century. It is not too surprising, given the turmoil affecting al‐Andalus and Maghrib
at that time, that a scholar from the westernmost part of the Islamic world would decide to
emigrate to Egypt, whose capital Cairo was already established as the major cultural center of the
Arab–Islamic world. Unfortunately, Marrākushī does not figure in any biographical sources, so we
must rely on the scanty evidence provided by his own work in order to shed some light on his life.
Marrākushī is best known for his remarkable summa devoted to spherical astronomy and
astronomical instrumentation, entitled Jāmiʿ al‐mabādiʾ wa‐ʾl‐ghāyāt fī ʿilm al‐mīqāt (Collection of
the principles and objectives in the science of timekeeping), which is intended as a comprehensive
encyclopedia of practical astronomy. This work is the single most important source for the history
of astronomical instrumentation in Islam. It was the standard reference work for Mamluk Egyptian
and Syrian, Rasūlid Yemeni, and Ottoman Turkish specialists of the subject.
This voluminous work (most complete copies cover 250 to 350 folios of text, diagrams, and tables)
has occasionally been qualified as a mere compilation of older sources without original contents.
While it is true that this synthetic work heavily depends upon the works of predecessors, it is
definitively original and without any precedent. In fact, no single part of the work can be proven to
reproduce the words of an earlier author, except for the few sections where Marrākushī clearly
states from whom he is quoting. In those occasional cases where an earlier source is mentioned,
Marrākushī's text always turns out to be either a major rewriting of the original or an independent
paraphrase.
The Jāmiʿ al‐mabādiʾ wa‐ʾl‐ghāyāt is well written and logically organized, and employs a relatively
literate style that is unusual for a work on technical topics. The author is clearly a very competent
astronomer and also occasionally displays his knowledge of ancillary disciplines such as philosophy.
The Jāmiҁ is made up of four books on the following topics:
From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers,
Springer Reference. New York: Springer, 2007, pp. 739-740
Courtesy of
http://dx.doi.org/10.1007/978-0-387-30400-7_905
(1) On calculations, in 67 chapters. This book gives exhaustive calculatory methods (without
proofs) concerning chronology, trigonometry, geography, spherical astronomy, prayer
times, the solar motion, the fixed stars, gnomonics, etc.
(2) On the construction of instruments, in seven parts. The first part concerns graphical
methods in spherical astronomy and gnomonics. The second through the seventh parts
then treat the construction of portable dials, fixed sundials, trigonometric and horary
quadrants, spherical instruments, instruments based upon projection, and observational
and planetary instruments.
(3) On the use of selected instruments, in 14 chapters.
(4) The work ends with a “quiz” – i.e., a series of questions and answers – in four chapters,
whose aim is to train the mental abilities of the students
An interesting confirmation of Marrākushī's Maghribi origin is provided by his geographical table:
44 of the 135 localities featured in the list of latitudes are written in red ink to indicate that the
author visited these places personally and determined their geographical latitude in situ through
observation. These 44 locations begin along the Atlantic coast of today's western Sahara, include
numerous cities and villages in the Maghrib, two cities in al‐Andalus (Seville and Cádiz), and
continue along the Mediterranean coast via Algiers, Tunis, and Tripoli to end up in Alexandria,
Cairo, Minya, and Tinnis. Marrākushī's western Islamic heritage is also apparent in the fact that his
chapters on precession and solar theory depend upon the works of Zarqālī and Ibn al‐Kammād.
Marrākushī appears to have written his major work in Cairo during the years 1276–1282. First, a
solar table is given for the year 992 of the Coptic calendar (Diocletian era), corresponding to the
years 1275/1276. Also, some examples of chronological calculations are given for the year
1281/1282, and his star table in equatorial coordinates is calculated for the end of the same year.
The arrival of Marrākushī in Cairo coincided with the establishment of the first offices of
muwaqqits (timekeepers) in Egyptian mosques. His work can thus be seen as fulfilling a specific
demand of Mamlūk Egyptian society (more specifically, the mosque administration, the muezzins
and muwaqqits, instrument‐makers, interested students, etc.). But the lack of any reference to the
profession of the muwaqqit or to the milieu of the mosque would seem to indicate that Marrākushī
was an independent scholar without institutional affiliation. The motive he gives for writing his
magnum opus is the inadequate education of instrument–makers and their methodological failures.
His introduction suggests that his target audience was instrument–makers, i.e. artisans and
practitioners of applied science, who were not professional astronomers. However, this is
somewhat contradicted by the technical level of the book, which certainly assumes the reader to
know at least the basics of arithmetic, geometry, spherics, algebra, and trigonometry. Thus the
Jāmiʿ al‐mabādiʾ wa‐ʾl‐ghāyāt seems more likely to be a comprehensive reference work of
intermediate to advanced level intended for active and apprentice muwaqqits, and for specialists of
timekeeping and instrumentation who were associated with them.
Marrākushī must have died, most probably in Cairo, between the years 1281/1282 and circa 1320,
since two early 14th‐century sources refer to him as being deceased (an anonymous treatise on
timekeeping entitled Kanz al‐yawāqīt, datable to 723 H/1323 and preserved in MS Leiden Or. 468,
Marrākushī was one of the major astronomers in 13th‐century Egypt. As his name indicates, he was
originally from Maghrib, but his major astronomical activities took place in Cairo during the second
half of the 13th century. It is not too surprising, given the turmoil affecting al‐Andalus and Maghrib
at that time, that a scholar from the westernmost part of the Islamic world would decide to
emigrate to Egypt, whose capital Cairo was already established as the major cultural center of the
Arab–Islamic world. Unfortunately, Marrākushī does not figure in any biographical sources, so we
must rely on the scanty evidence provided by his own work in order to shed some light on his life.
Marrākushī is best known for his remarkable summa devoted to spherical astronomy and
astronomical instrumentation, entitled Jāmiʿ al‐mabādiʾ wa‐ʾl‐ghāyāt fī ʿilm al‐mīqāt (Collection of
the principles and objectives in the science of timekeeping), which is intended as a comprehensive
encyclopedia of practical astronomy. This work is the single most important source for the history
of astronomical instrumentation in Islam. It was the standard reference work for Mamluk Egyptian
and Syrian, Rasūlid Yemeni, and Ottoman Turkish specialists of the subject.
This voluminous work (most complete copies cover 250 to 350 folios of text, diagrams, and tables)
has occasionally been qualified as a mere compilation of older sources without original contents.
While it is true that this synthetic work heavily depends upon the works of predecessors, it is
definitively original and without any precedent. In fact, no single part of the work can be proven to
reproduce the words of an earlier author, except for the few sections where Marrākushī clearly
states from whom he is quoting. In those occasional cases where an earlier source is mentioned,
Marrākushī's text always turns out to be either a major rewriting of the original or an independent
paraphrase.
The Jāmiʿ al‐mabādiʾ wa‐ʾl‐ghāyāt is well written and logically organized, and employs a relatively
literate style that is unusual for a work on technical topics. The author is clearly a very competent
astronomer and also occasionally displays his knowledge of ancillary disciplines such as philosophy.
The Jāmiҁ is made up of four books on the following topics:
From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers,
Springer Reference. New York: Springer, 2007, pp. 739-740
Courtesy of
http://dx.doi.org/10.1007/978-0-387-30400-7_905
(1) On calculations, in 67 chapters. This book gives exhaustive calculatory methods (without
proofs) concerning chronology, trigonometry, geography, spherical astronomy, prayer
times, the solar motion, the fixed stars, gnomonics, etc.
(2) On the construction of instruments, in seven parts. The first part concerns graphical
methods in spherical astronomy and gnomonics. The second through the seventh parts
then treat the construction of portable dials, fixed sundials, trigonometric and horary
quadrants, spherical instruments, instruments based upon projection, and observational
and planetary instruments.
(3) On the use of selected instruments, in 14 chapters.
(4) The work ends with a “quiz” – i.e., a series of questions and answers – in four chapters,
whose aim is to train the mental abilities of the students
An interesting confirmation of Marrākushī's Maghribi origin is provided by his geographical table:
44 of the 135 localities featured in the list of latitudes are written in red ink to indicate that the
author visited these places personally and determined their geographical latitude in situ through
observation. These 44 locations begin along the Atlantic coast of today's western Sahara, include
numerous cities and villages in the Maghrib, two cities in al‐Andalus (Seville and Cádiz), and
continue along the Mediterranean coast via Algiers, Tunis, and Tripoli to end up in Alexandria,
Cairo, Minya, and Tinnis. Marrākushī's western Islamic heritage is also apparent in the fact that his
chapters on precession and solar theory depend upon the works of Zarqālī and Ibn al‐Kammād.
Marrākushī appears to have written his major work in Cairo during the years 1276–1282. First, a
solar table is given for the year 992 of the Coptic calendar (Diocletian era), corresponding to the
years 1275/1276. Also, some examples of chronological calculations are given for the year
1281/1282, and his star table in equatorial coordinates is calculated for the end of the same year.
The arrival of Marrākushī in Cairo coincided with the establishment of the first offices of
muwaqqits (timekeepers) in Egyptian mosques. His work can thus be seen as fulfilling a specific
demand of Mamlūk Egyptian society (more specifically, the mosque administration, the muezzins
and muwaqqits, instrument‐makers, interested students, etc.). But the lack of any reference to the
profession of the muwaqqit or to the milieu of the mosque would seem to indicate that Marrākushī
was an independent scholar without institutional affiliation. The motive he gives for writing his
magnum opus is the inadequate education of instrument–makers and their methodological failures.
His introduction suggests that his target audience was instrument–makers, i.e. artisans and
practitioners of applied science, who were not professional astronomers. However, this is
somewhat contradicted by the technical level of the book, which certainly assumes the reader to
know at least the basics of arithmetic, geometry, spherics, algebra, and trigonometry. Thus the
Jāmiʿ al‐mabādiʾ wa‐ʾl‐ghāyāt seems more likely to be a comprehensive reference work of
intermediate to advanced level intended for active and apprentice muwaqqits, and for specialists of
timekeeping and instrumentation who were associated with them.
Marrākushī must have died, most probably in Cairo, between the years 1281/1282 and circa 1320,
since two early 14th‐century sources refer to him as being deceased (an anonymous treatise on
timekeeping entitled Kanz al‐yawāqīt, datable to 723 H/1323 and preserved in MS Leiden Or. 468,
Selected References
Al‐Marrākushī, Abū al‐Ḥasan ʿAlī (1984). Jāmiʿ al‐mabādīʾ wa‐ʾl‐ghāyāt fī ʿilm al‐mīqāt. Facsimile edition. Frankfurt am Main. Partially translated in J. J. Sédillot, Traité des instruments astronomiques des arabes, Paris, 1834–1835. (Reprint, Frankfurt, 1984); L. A. Sédillot, “Mémoire sur les instruments astronomiques des arabes,” Mémoires de l'Académie royale des inscriptions et belles‐lettres de l'Institut de France 1 (1894): 1–229. (Reprint, Frankfurt, 1989.)
Al‐Qifṭī, Jamāl al‐Dīn Akhbār al‐ʿulamāʾ bi‐akhbār al‐ḥukamāʾ. Beirut, n.d.
Boutelle, Marion (1967). “The Almanac of Azarquiel.” Centaurus 12: 12–20.
Comes, Mercè (1991). Ecuatorios andalusíes: Ibn al‐Samḥ, al‐Zarqālluh y Abū‐l‐Ṣalt. Barcelona.
Goldstein, Bernard R. (1964). “On the Theory of Trepidation according to Thābit b. Qurra and al‐Zarqāllu and Its Implications for Homocentric Planetary Theory.” Centaurus 10: 232–247.
Ibn al‐Abbār (1920). Al‐Takmila li‐kitāb al‐Sila, edited by A. Bel and M. Ben Cheneb. Algiers.
Israeli, R. Isaac (1946–1948). Liber Jesod olam seu Fundamentum mundi, edited by B. Goldberg and L. Rosenkranz, with commentary by D. Cassel. Berlin.
King, David A. (1986). A Survey of the Scientific Manuscripts in the Egyptian National Library. Winona Lake, Indiana: Eisenbrauns.
——— (1997). “S‐h‐akkāziyya.” In Encyclopaedia of Islam. 2nd ed. Vol. 9, pp. 251–253. Leiden: E. J. Brill.
Mercier, Raymond (1987). “Astronomical Tables in the Twelfth Century.” In Adelard of Bath: An English Scientist and Arabist of the Early Twelfth Century, edited by Charles Burnett, pp. 87–118. London: Warburg Institute. (See pp. 104–112.)
Millás Vallicrosa, José María (1932). “La introducción del cuadrante con cursor en Europa.” Isis 17: 218–258. (Reprinted in Millás Vallicrosa, Estudios sobre historia de la ciencia española. Barcelona, 1949.)
——— (1943–1950). Estudios sobre Azarquiel. Madrid–Granada.
Puig, Roser (1985). “Concerning the safīḥa shakkāziyya.” Zeitschrift für Geschichte der arabisch–islamischen Wissenschaften 2: 123–139.
——— (1987). Los tratados de construcción y uso de la azafea de Azarquiel. Madrid.
——— (2000). “The Theory of the Moon in the Al‐Zīj al‐Kāmil fī‐l‐Taʿālīm of Ibn al‐Hāʾim (ca. 1205).” Suhayl 1: 71–99.
——— (1986). Al‐šakkāziyya: Ibn al‐Naqqāš al‐Zarqālluh. Edición, traducción y estudio. Barcelona.
Rico y Sinobas, Manuel (1863–1867). Libros del saber de astronomía del rey D. Alfonso X de Castilla, copilados, anotados y comentados por Don Manuel Rico y Sinobas. 5 Vols. Madrid.
Richter‐Bernburg, Lutz (1987). “Ṣāʿid, the Toledan Tables, and Andalusī Science.” In From Deferent to Equant: A Volume of Studies in the History of Science in the Ancient and Medieval Near East in Honor of E. S. Kennedy, edited by David A. King and George Saliba, pp. 373–401. Annals of the New York Academy of Sciences. Vol. 500. New York: New York Academy of Sciences.
Ṣāʿid al‐Andalusī (1985). Kitāb Tabaqāt al‐umam, edited by Hayāt Bū ʿAlwān. Beirut. (French translation with notes by Régis Blachère as Livre des catégories des nations. Paris: Larose, 1935.)
Samsó, Julio (1992). Las ciencias de los antiguos en al‐Andalus. Madrid: Mapfre.
——— (1994). “Trepidation in al‐Andalus in the 11th Century.” In Islamic Astronomy and Medieval Spain, VIII. Aldershot: Variorum.
——— (1994). “Sobre el modelo de Azarquiel para determinar la oblicuidad de la eclíptica.” In Islamic Astronomy and Medieval Spain, IX. Aldershot: Variorum.
——— (1994). “Ibn al‐Bannāʾ, Ibn Ishāq and Ibn al‐Zarqālluh's Solar Theory.” In Islamic Astronomy and Medieval Spain, X. Aldershot: Variorum.
——— (2002). “Al‐Zarkālī.” In Encyclopaedia of Islam. 2nd ed. Vol. 11, pp. 461–462. Leiden: E. J. Brill.
Samsó, Julio and Honorino Mielgo (1994). “Ibn al‐Zarqālluh on Mercury.” Journal for the History of Astronomy 25: 289–296.
Sesiano, Jacques (1996). Un traité médiéval sur les carrés magiques: De l'arrangement harmonieux des nombres. Lausanne: Presses polytechniques et universitaires romandes.
Toomer, G. J. (1968). “A Survey of the Toledan Tables.” Osiris 15: 5–174.
——— (1969). “The Solar Theory of az‐Zarqāl: A History of Errors.” Centaurus 14: 306–336.
——— (1987). “The Solar Theory of az‐Zarqāl: An Epilogue.” In From Deferent to Equant: A Volume of Studies in the History of Science in the Ancient and Medieval Near East in Honor of E. S. Kennedy, edited by David A. King and George Saliba, pp. 513–519. Annals of the New York Academy of Sciences. Vol. 500. New York: New York Academy of Sciences.
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