Ibn al-Ha'im al-Ishbili

Ibn al‐Hāʾim originated from Seville in Al-Andalus. As a student, he learnt mathematics using the works of the scholars Al-Jayyani and Jabir ibn Aflah. He probably worked in North Africa, at a time when the Almohad Caliphate ruled the region. Ibn al‐Hāʾim became proficient at mathematics and was familiar with the trigonometrical concepts introduced into al‐Andalus by the scholar Ibn Mu'adh al-Jayyani in the 11th century and developed during the next century by the astronomer and mathematician Jābir ibn Aflaḥ.[1]

In 1204/5 Ibn al‐Hāʾim wrote al‐Zīj al‐kāmil fī al‐talim ("The Perfect Handbook on Mathematical Astronomy"), a treatise that consisted of an introduction and seven books. A zīj in all but name, the information it contains does not include any numerical tables.[1] It was considered exceptionally complete and accurate by Islamic medieval astronomers, and he had a great influence on the development of astronomy in the Maghreb.[2]

The work has provided modern historians with important information on earlier astronomers in al‐Andalus. It gives historical data on the life and works of the instrument maker and astrologer Al-Zarqali and the creation of the Tables of Toledo by astronomers in Toledo patronized by the qadi Said Al-Andalusi.

Ibn al‐Hāʾim further extended Al-Zarqali's theories on the oscillation of the obliquity of the ecliptic, presented spherical trigonometrical formulae, gives a longitude of the solar apogee of 85° 49′ and further confirmed the works of Al-Zarqali. The work also deals with the computation of the Moon's longitude and latitude, attempting to correct Ptolemy's theory.[1]

A copy of the manuscript is held at the Bodleian Library at Oxford, UK.[3]

• Puig, Roser (2007). "Ibn al‐Hāʾim: Abū Muḥammad ʿAbd al‐Ḥaqq al‐Ghāfiqī al‐Ishbīlī". In Thomas Hockey; et al. (eds.). The Biographical Encyclopedia of Astronomers. New York: Springer Publishers. ISBN 978-0-387-31022-0. (PDF version)
• Samsó, Julio (1997). "Ibn al‐Hāʾim". In Helaine Selin (ed.). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Kluwer Academic Publishers. ISBN 9780792340669.

• Samso, Julio (2013). "Ibn al‐Hāʾim". In Selin, Helaine (ed.). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Berlin: Springer Nature. p. 405. ISBN 978-94017-1-416-7.