Al-Sufi's Star Catalogue

A depiction of a Medieval Islamic astronomer. Thought by some to represent Abd al-Rahman al-Sufi.

The illustration above is a section of a painting showing workers at the observatory of Taqi al-Din at Istanbul in 1577. The particular painting is from the epic poem Shahinshah-nama by 'Ala ad-Din Mansur-Shiazi. It was written in honour of Sultan Murad III who reigned from 1574 to 1595. Though it is common to speak of Arabic astronomy the more correct term would be Arab-Islamic astronomy. Many of the astronomers (and peoples) were not Arabs but were from the regions of (modern-day) Iran, Iraq, and Afghanistan. Arabic was the scientific language and lingua franca for followers of the Islamic religion. The language of the religion was Arabic. It is correct to speak of Greek science being passed to the Arabs. Arab rulers of Arab states, for example the 'Umayyad dynasty (which collapsed in the 740s), funded and patronised the transmission process through Syriac sources. The 'Abbasid dynasty which followed can also be considered as an Arab regime.

A page from Al-Sufi's book on the constellations Kitab suwar al-kawakib (Book of the constellations of the Fixed Stars). The book was written for and dedicated to the Buwayhid ruler Fana Khusrau, titled Adud al-Dawla (made Emir of Iraq in 949 CE and died in 982 CE), who was a great patron of astronomy and had erected an observatory at Shiraz. Al-Sufi’s main source for his treatise is the star-catalogue compiled by the Alexandrian astronomer Ptolemy (called "BatlamiyUs" in Arabic). Ptolemy's star-catalogue was included in his major work Mathematika Syntaxis. In the preface to Kitab suwar al-kawakib, al-Sufi mentions that he referred to as many translations of the Almagest as he could find, having noticed discrepancies between them. Paul Kunitzsch has noted that al-Sufi's treatise mostly follows the wording of Isliaq b. Ijunayn's translation, but obtains star-positions from a range of versions.

Al-Sufi’s best known work is Kitab suwar al-kawakib (Book of the constellations of the Fixed Stars). "Fixed Stars" is a term describing the stars, which were thought to be fixed to the surface of a large celestial sphere, turning around the Earth. (The "Wandering Stars" are the planets, which were seen to move independently and at different paces, across the celestial sphere.)

Knowledge of the fixed stars in Greek-based Arab-Islamic astronomy was derived mainly from Ptolemy's Almagest which contained a catalogue of 1025 stars arranged in 48 constellations (circa 150 CE). The first critical revision of Ptolemy's catalogue of fixed stars was carried out by al-Sufi. However, al-Sufi adopted Ptolemy's basic scheme and pattern of constellations. He did not add or subtract stars from Ptolemy's star list and neither did he re-measure their (frequently incorrect) positions. Also, though al-Sufi based his constellation drawings (figures) on the classical Aratean tradition his figures have a distinct oriental character.

Arabic translations of Ptolemy’s Mathematika Syntaxis were made during the 9^th- century, including those of Sahi al-Tabari, al-Hajjãj b. Yusuf b. Matar, and Isaq b. llunayn (died 877 CE), whose 827/828 CE version was later corrected by Thäbit b. Qurra (died 90 l CE).

Abd al-Rahman al-Sufi (Al-Sufi; known in Western Europe by the Latinized name Azophi) was born in 903 CE in Rayy (near modern Tehran), Persia and died in 986 CE. Al-Sufi lived and worked mostly in Isfahan (Persia) at the court of Emir Adud ad-Daula. (He worked in both Isfahan (Iran) and Baghdad (Iraq).) He is most widely known, and became most influential, for his translation and partial revision of Ptolemy's star catalogue as the Book of the constellations of the Fixed Stars (Kitab suwar al-kawakib). It was published circa 964 CE and it was frequently copied and translated. It had considerable influence on European astronomy.

Al-Sufi was both a translator and author. He was involved in translating Hellenistic astronomical works (that had been centred in Alexandria) into Arabic, especially Ptolemy's Almagest. He wrote numerous works on astronomical, astrological, and mathematical subjects. His most outstanding work is his illustrated book on the constellations (Kitab suwar al-kawakib). In this work he comprehensively describes the 48 classical constellations, which were established by Ptolemy and transmitted to the Islamic world in translations of Ptolemy's Almagest. Like all other Islamic scholars of the period he wrote all his works in Arabic (the scientific language of the Arab-Islamic world). In producing his own version of the star catalogue in Ptolemy's Almagest al-Sufi introduced many traditional Arabic star names. (Most star names used by al-Sufi (and his contemporaries) were direct translations of Ptolemy's descriptions.) It was the first attempt to relate (integrate/synthesise) the Greek stars of Ptolemy's star catalogue with the indigenous (traditional) Arabic star names and constellations (the Arab anwa tradition). Because some of the Arabic star names were centuries old their meanings were lost to al-Sufi and his contemporaries, and they remain unknown today. Another problem is that al-Sufi used anwa texts from the Islamic period as his sources. This somewhat limits their connection with indigenous pre-Islamic Arabic anwa traditions.

In Kitab suwar al-kawakib the description of each constellation comprises the following four sections: (1) A general discussion of the constellation and its individual stars. Also included in this section is al-Sufi's criticism of the Ptolemaic tradition and also notices of al-Sufi's own observations. (He described all the stars catalogued by Ptolemy and added his own criticism in each individual case.) (2) A record of the indigenous Arabic star names falling within each constellation, and the exact identification of each of these stars with the corresponding Ptolemaic stars. (3) Two drawings of the constellations, one depicting the constellation as it is seen on the celestial globe (i.e., as seen by an observer looking inwards towards earth), and the other one as it is seen in the sky (i.e., as seen by an observer looking outwards from earth). (4) A table of the stars making up each of the constellations, including a verbal description of each star's location and its longitude, latitude, and magnitude. (The magnitudes given were according to al-Sufi's own observations.) This table closely follows the arrangement of Ptolemy's star catalogue in the Almagest. In this book al-Sufi also described the boundaries of the constellations.

In al-Sufi's Kitab suwar al-kawakib the constellation figures and the individual stars comprising them are shown separately (i.e., separated from each other) without any information on their relative positions being given. No sky map (with all the constellations charted) appears in the book.

Al-Sufi's book on the constellations (and the constellation drawings contained in it) served as models for further work on the fixed stars in the Arab-Islamic world for many centuries. His description of the constellations became the basis for all later studies. (Al-Sufi's drawings of the constellation figures established a standard typology for the constellations.) Islamic constellation figures were introduced into Europe as least as early as the 13th-century. It is stated by some sources that al-Sufi's Kitab suwar al-kawakib was never translated into Latin. This is incorrect. A fully illustrated translation was (anonymously?) made in Palermo, Sicily, in the 12th-century at the instigation of Guillaumine II (1166-1189).the Norman king of Sicily. (A Latin manuscript of it, titled Liber de locis stellarum fixarum, now resides at the Arsenal Library in Paris as part of MS # 1036 (a collection of astronomical manuscripts with the general title Liber de stellis stellarum). The Liber de locis stellarum fixarum contains 49 illustrations representing the constellations and the signs of the zodiac. The Arabic-Persian iconography, based on characters in the One Thousand and One Nights story, is kept. The Parisian copy, made anonymously, is the oldest existing Latin copy. It is dated to the third quarter of the 13th-century and is believed to be a copy of the translation made earlier in Sicily. (It is sometimes identified as being made from a manuscript in Spain.) (The Holy Roman Emperor Frederick II, at his court in Palermo, Sicily, financed translations of Arabic works into Latin.) Al-Sufi's book was also fully translated into Spanish by Alfonso X ("Alfonso the Wise") of Leon and Castile, as Libros del Saber de Astronomia. It was through these translations that it influenced the star names of used in western Europe. Its contents were transmitted into Europe and in medieval Europe its constellation drawings were imitated in numerous Latin astronomical manuscripts.

Petrus Apianus (Peter Apian) (1495-1552) the 16th-century German astronomer and geographer took star names from al-Sufi's book on the constellations and placed them on his star charts and mentioned them in his writings. (See the chapter on the constellations in his Astronomicum Caesareum (1540).)

It has been long believed that al-Sufi's book on the constellations was the (exclusive) key source for the establishment of star names in western Europe. (Note: A few proper star names, such as Polaris (North Star), are not Arabic.) However, this now appears to be over-simplified and somewhat incorrect. The science historian Owen Gingerich writes ("Islamic Astronomy," Scientific American, Volume 254, April, 1986, Pages 68-?): "It now seems that his [i.e., Ptolemy's] 14th- and 15th-century Latin translators went to a Latin version of the Arabic edition of Ptolemy himself for the star descriptions, which they combined with al-Sufi's splendid pictorial representations of the constellations. Meanwhile the Arabic star nomenclature trickled into the West by another route: the making of astrolabes." (Some of these astrolabes have distorted Arabic names for stars.)

The astrolabe, essentially a two-dimensional model of the sky, was originally a Greek invention (dating circa 3rd-century BCE) to enable the problems of spherical astronomy (i.e., the prediction of star positions) to be solved. It moved with the spread of Islam through North Africa into Spain (Andalusia). It would appear that England, due to the scientific activity centred at Oxford, was the conduit for the introduction of the astrolabe from Spain into western Europe in the late 13th-century and the 14th-century.

Historians have not settled the debate over who was responsible for the transmission of the astrolabe from Muslim Spain into Europe and when and where the astrolabe first appeared in Europe. However, by 1030 CE at the latest some European scholars possessed astrolabes and were teaching their use. Early Christian recipients of Arab astronomy (including the astrolabe) included Gerbert of Aurillac and Hermannus Contractus. Gerbert of Aurillac (circa 946-1003 CE) (later to become Pope Sylvester II (999 - 1003 CE)) spent several years (967-969 CE) studying in Spain in the Christian-held city of Barcelona and also possibly in the Moorish-held cities of Córdoba and Seville. (He originally went to the cathedral school of Vic, in the province of Catalonia which was on the frontier of Moorish Spain. As a result there was considerable communication between Catalunya and the Muslims of al-Andalus to the south.) It is thought that Gerbert of Aurillac may have been the author of a description of the astrolabe ( The Book of the Astrolabe which was the first Latin text explaining the astrolabe and providing instructions for the construction of an astrolabe) that was edited by the Benedictine monk Hermannus Contractus (1013-1054 CE) some 50 years later.

Many of these early astrolabes that were introduced into Europe carried both Arabic and Latin star nomenclature. It has been noted by Paul Kunitzsch that star names that appear on medieval astrolabes in Europe are often quite different from star names that appear in star lists in medieval manuscripts. The astrolabe was widely used in Europe during the late Middle Ages and the Renaissance with its popularity peaking in the 15th- and 16th-centuries. (The astrolabes of the 11th-16th centuries were an important instrument for predicting star positions.) It became one of the basic astronomical education tools. Europeans eventually began to manufacture astrolabes. In the 15th-century European astrolabe manufacturing was centred in Augsberg and Nuremberg in Germany, with some manufacturing also in France. By the middle of the 17th-century astrolabes were being manufactured all over Europe.

(The astrolabe was a 'flattened' and more portable version of the armillary sphere. It was a two-dimensional representation of the celestial sphere and was used for solving problems in celestial geography.)

Islamic astronomical globes also became highly prized in medieval western Europe. Some were purchased and used without translation of Arabic terms as Arabic was a scientific language in medieval Europe. Some were purchased and copied with the names of stars and constellations being translated into Latin versions of Arabic. Arabic was frequently used on European globes along with other scientific languages. Globes were manufactured and used with astronomical terms in Latin, Greek, and Arabic.

European astronomers and celestial map makers began to use Arabic star names in preference to Latin names circa 12th-century CE. This practice kept on increasing with the increasing ease of European access to Islamic texts and instruments. By the end of the 15th-century the process of European adoption of Arabic star names was essentially complete. (According to Emilie Savage-Smith it has been established that a nearly complete Arabic version of al-Sufi's treatise on the constellations must have reached Germany by the 1530's, for information in it was employed in a limited way by Peter Apian, who from 1527 to 1552 was professor of mathematics at the University of Ingolstadt.) The "Arabic" names were retained in the formal, scientific nomenclature until the end of the 19th-century.

Al-Sufi's star catalogue was in turn revised by the the 15th-century Timurid governor (of Transoxiana and Turkestan) and astronomer Ulugh Beg, at his observatory in Samarkand, Uzbekistan.