} Abu Muhammad Abd al-Haqq al‐Ghafiqi al‐Ishbili (), also known as Ibn al‐Hāʾim (fl. was a medieval Muslim astronomer and

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

from

Seville Seville (; es, Sevilla, ) is the capital and largest city of the Spanish autonomous community of Andalusia and the province of Seville. It is situated on the lower reaches of the River Guadalquivir, in the southwest of the Iberian Peninsula ...

. He is known to modern scholars for his (1204/5), which was had a great influence on the development of Islamic astronomy and which has provided important information on astronomers from

Al-Andalus Al-Andalus translit. ; an, al-Andalus; ast, al-Ándalus; eu, al-Andalus; ber, ⴰⵏⴷⴰⵍⵓⵙ, label= Berber, translit=Andalus; ca, al-Àndalus; gl, al-Andalus; oc, Al Andalús; pt, al-Ândalus; es, al-Ándalus () was the M ...

, including the instrument maker and astrologer Al-Zarqali.

Life

Ibn al‐Hāʾim originated from

. As a student, he learnt mathematics using the works of the scholars

Al-Jayyani Abū ʿAbd Allāh Muḥammad ibn Muʿādh al-Jayyānī ( ar, أبو عبد الله محمد بن معاذ الجياني; 989, Cordova, Al-Andalus – 1079, Jaén, Al-Andalus) was an Arab, mathematician, Islamic scholar, and Qadi from Al-Anda ...

and

Jabir ibn Aflah Abū Muḥammad Jābir ibn Aflaḥ ( ar, أبو محمد جابر بن أفلح, la, Geber/Gebir; 1100–1150) was an Arab Muslim astronomer and mathematician from Seville, who was active in 12th century al-Andalus. His work ''Iṣlāḥ al-Ma ...

. 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.

In 1204/5 Ibn al‐Hāʾim wrote ("''The Perfect Handbook on Mathematical Astronomy''"), a
treatise A treatise is a formal and systematic written discourse on some subject, generally longer and treating it in greater depth than an essay, and more concerned with investigating or exposing the principles of the subject and its conclusions." Tre ...
that consisted of an introduction and seven books. A in all but name, the information it contains does not include any numerical tables. 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 The Maghreb (; ar, الْمَغْرِب, al-Maghrib, lit=the west), also known as the Arab Maghreb ( ar, المغرب العربي) and Northwest Africa, is the western part of North Africa and the Arab world. The region includes Algeria, ...
. 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 The ''Toledan Tables'', or ''Tables of Toledo'', were astronomical tables which were used to predict the movements of the Sun, Moon and planets relative to the fixed stars. They were a collection of mathematic tables that describe different aspe ...
'' by astronomers in Toledo patronized by the
Said Al-Andalusi Ṣāʿid al-Andalusī (); he was Abū al-Qāsim Ṣāʿid ibn Abū al-Walīd Aḥmad ibn Abd al-Raḥmān ibn Muḥammad ibn Ṣāʿid ibn ʿUthmān al-Taghlibi al-Qūrtūbi () (1029July 6, 1070 AD; 4206 Shawwal, 462 AH); an Arab qadi of Toledo ...
. Ibn al‐Hāʾim further extended Al-Zarqali's theories on the
oscillation Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...
of the
obliquity of the ecliptic In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle between its equatorial plane and o ...
, presented spherical trigonometrical formulae, gives a
longitude Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lette ...
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 Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importance ...
's theory. A copy of the
manuscript A manuscript (abbreviated MS for singular and MSS for plural) was, traditionally, any document written by hand – or, once practical typewriters became available, typewritten – as opposed to mechanically printed or reproduced in ...
is held at the Bodleian Library at
Oxford Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the ...
, UK.

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Life

Notes

Sources

Further reading