World Library  
Flag as Inappropriate
Email this Article

Abū Ishāq Ibrāhīm al-Zarqālī


Abū Ishāq Ibrāhīm al-Zarqālī

Abū Isḥāq Ibrāhīm ibn Yaḥyā al-Naqqāsh al-Zarqālī, also known as Al-Zarkali or Ibn Zarqala (1029–1087), was a Muslim instrument maker, astrologer, and one of the leading astronomers of his time. Although his name is conventionally given as al-Zarqālī, it is probable that the correct form was al-Zarqālluh.[1] In Latin he is referred to as Arzachel or Arsechieles, a modified form of Arzachel, meaning 'the engraver'.[2] He lived in Toledo, Al-Andalus before moving to Córdoba later in his life. His works inspired a generation of Islamic astronomers in Al-Andalus.

The crater Arzachel on the Moon is named after him.[2]


  • Early life 1
  • Science 2
    • Instruments 2.1
    • Theory 2.2
    • Tables of Toledo 2.3
  • Works 3
  • See also 4
  • Notes 5
  • Further reading 6
  • External links 7

Early life

Al-Zarqālī was born in a village near the outskirts of Toledo, then the capital of the Taifa of Toledo.

Art from Toledo in Al-Andalus depicting the Alcázar in the year 976.AD

He was trained as a metalsmith and due to his skills he was nicknamed Al-Nekkach "the engraver of metals"). His Latinized name, 'Arzachel' is formed from the Arabic al-Zarqali al-Naqqash, meaning 'the engraver'.[2]

He was particularly talented in Geometry and Astronomy. He is known to have taught and visited Córdoba on various occasions his extensive experience and knowledge eventually made him the foremost astronomer of his time. Al-Zarqālī was also an inventor, and his works helped to put Toledo at the intellectual center of Al-Andalus. He is also referred to in the works of Chaucer, as 'Arsechieles'.[2]

In the year 1085 Toledo was taken by the Christian king of Castile Alfonso VI. Al-Zarqālī and his colleagues, such as Al‐Waqqashi (1017–1095) of Toledo, had to flee. It is unknown whether the aged Al-Zarqālī fled to Cordoba or died in a Moorish refuge camp.

His works influenced Ibn Bajjah (Avempace), Ibn Tufail (Abubacer), Ibn Rushd (Averroës), Ibn al-Kammad, Ibn al‐Haim al‐Ishbili and Nur ad-Din al-Betrugi (Alpetragius).

In the 12th century, [3]



Al-Zarqālī wrote two works on the construction of an instrument (an equatorium) for computing the position of the planets using diagrams of the Ptolemaic model. These works were translated into Spanish in the 13th century by order of King Alfonso X in a section of the Libros del Saber de Astronomia entitled the "Libros de las laminas de los vii planetas".

He also invented a perfected kind of astrolabe known as "the tablet of the al-Zarqālī" (al-ṣafīḥā al-zarqāliyya), which was famous in Europe under the name Saphaea.[4][5]

There is a record of an al-Zarqālī who built a water clock, capable of determining the hours of the day and night and indicating the days of the lunar months.[6] According to a report found in al-Zuhrī's Kitāb al-Juʿrāfīyya, his name is given as Abū al-Qāsim bin ʿAbd al-Raḥmān, also known as al-Zarqālī, which made some historians think that this is a different person.[1]


Al-Zarqali corrected geographical data from [3] In his treatise on the solar year, which survives only in a Hebrew translation, he was the first to demonstrate the motion of the solar apogee relative to the fixed background of the stars. He measured its rate of motion as 12.9 seconds per year, which is remarkably close to the modern calculation of 11.6 seconds.[7] Al-Zarqālī's model for the motion of the Sun, in which the center of the Sun's deferent moved on a small, slowly rotating circle to reproduce the observed motion of the solar apogee, was discussed in the thirteenth century by Bernard of Verdun[8] and in the fifteenth century by Regiomontanus and Peurbach. In the sixteenth century Copernicus employed this model, modified to heliocentric form, in his De Revolutionibus Orbium Coelestium.[9]

Tables of Toledo

Al-Zarqālī also contributed to the famous Tables of Toledo, an adaptation of earlier astronomical data to the location of Toledo along with the addition of some new material.[1] Al-Zarqālī was famous as well for his own Book of Tables. Many "books of tables" had been compiled, but his almanac contained tables which allowed one to find the days on which the Coptic, Roman, lunar, and Persian months begin, other tables which give the position of planets at any given time, and still others facilitating the prediction of solar and lunar eclipses.

He also compiled an almanac that directly provided "the positions of the celestial bodies and need no further computation". The work provided the true daily positions of the sun for four Julian years from 1088 to 1092, the true positions of the five planets every 5 or 10 days over a period of 8 years for Venus, 79 years for Mars, and so forth, as well as other related tables.[10][11]

His Zij and Almanac were translated into Latin by Gerard of Cremona in the 12th century, and contributed to the rebirth of a mathematically based astronomy in Christian Europe and were later incorporated into the Tables of Toledo in the 12th century and the Alfonsine tables in the 13th century.[10]

In designing an instrument to deal with Ptolemy's complex model for the planet Mercury, in which the center of the deferent moves on a secondary epicycle, al-Zarqālī noted that the path of the center of the primary epicycle is not a circle, as it is for the other planets. Instead it is approximately oval and similar to the shape of a pignon.[12] Some writers have misinterpreted al-Zarqālī's description of an earth-centered oval path for the center of the planet's epicycle as an anticipation of Johannes Kepler's sun-centered elliptical paths for the planets.[13] Although this may be the first suggestion that a conic section could play a role in astronomy, al-Zarqālī did not apply the ellipse to astronomical theory and neither he nor his Iberian or Maghrebi contemporaries used an elliptical deferent in their astronomical calculations.[14]


Major Works and publications :

  • 1-"Al Amal bi Assahifa Az-Zijia";
  • 2-"Attadbir";
  • 3-"Al Madkhal fi Ilm Annoujoum";
  • 4-"Rissalat fi Tarikat Istikhdam as-Safiha al-Moushtarakah li Jamiâ al-ouroud";
  • 5-"Almanac Arzarchel";

See also


  1. ^ a b c s.v. "al-Zarqālī", Julio Samsó, Encyclopaedia of Islam, New edition, vol. 11, 2002.
  2. ^ a b c d e
  3. ^ a b
  4. ^ M. T. Houtsma and E. van Donzel (1993), "ASṬURLĀB", E. J. Brill's First Encyclopaedia of Islam, Brill Publishers, ISBN 90-04-08265-4
  5. ^
  6. ^ John David North, Cosmos: an illustrated history of astronomy and cosmology, University of Chicago Press, 2008, p. 218 "He was a trained artisan who entered the service of Qadi Said as a maker of instruments and water-clocks."
  7. ^ , at pp. 314–17.
  8. ^ .
  9. ^ , at pp. 308–10.
  10. ^ a b
  11. ^ , at p. 314.
  12. ^ Willy Hartner, "The Mercury Horoscope of Marcantonio Michiel of Venice", Vistas in Astronomy, 1 (1955): 84–138, at pp. 118–122.
  13. ^ Asghar Qadir (1989). Relativity: An Introduction to the Special Theory, pp. 5–10. World Scientific. ISBN 9971-5-0612-2.
  14. ^

Further reading

  • (PDF version)
  • E. S. Kennedy. A Survey of Islamic Astronomical Tables, (Transactions of the American Philosophical Society, New Series, 46, 2.) Philadelphia, 1956.

External links

  • Muslim Scientists Before the Renaissance: Abū Ishāq Ibrāhīm al-Zarqālī (Arzachel)
  • 'Transmission of Muslim astronomy to Europe'
  • 'An Extensive biography'
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.