Muḥyī al‐Milla wa al‐Dīn Yaḥyā Abū ʿAbdallāh ibn Muḥammad ibn Abī al‐Shukr al‐Maghribī al‐Andalusī ( ar, محيي الدين المغربي; died 1283 CE) was an Andalusī

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

, astrologer 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 ...

of the

Islamic Golden Age The Islamic Golden Age was a period of cultural, economic, and scientific flourishing in the history of Islam, traditionally dated from the 8th century to the 14th century. This period is traditionally understood to have begun during the reign ...

. He belonged to the group of astronomers associated with the

Maragheh observatory The Maragheh observatory (Persian: رصدخانه مراغه), also spelled Maragha, Maragah, Marageh, and Maraga, was an astronomical observatory established in the mid 13th century under the patronage of the Ilkhanid Hulagu and the directorship ...

, most notably Nasir al-Din al-Tusi. In astronomy, Ibn Abi al-Shukr carried out a large‐scale project of systematic planetary observations, which led to the development of several new astronomical parameters.
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He died in

Maragheh Maragheh ( fa, مراغه, Marāgheh or ''Marāgha''; az, ماراغا ) is a city and capital of Maragheh County, East Azerbaijan Province, Iran. Maragheh is on the bank of the river Sufi Chay. The population consists mostly of Iranian Azerba ...

in modern-day

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

in June 1283 CE.

Time in the Maragheh Observatory

Before joining in the Maghrib observatory, which was founded by the Mongol Ilkhanid dynasty in Iran, Muhyi al-Dīn al-Maghribī had worked for King Nasir of Damascus. This relationship was ultimately cut short when in 1257, the king was killed by the Mongols in the Siege of Aleppo conflict. It was after this that Muhyi al-Dīn al-Maghribī was sent to

to work alongside Nasir al-Din al-Tusi in the acclaimed observatory, and continued to work on his numerous observations until his death in 1283. During his time at the observatory, the amount of observations conducted by al-Maghribī was extensive, observing up to a total of eight of the brightest stars, of which he used the latitudes collected to compare with the values within ancient computations. He concluded that the difference between his latitudes and ancients were not substantial, and any inconsistences were in fact due to the observations and not the subject itself. In Muhyi al-Dīn al-Maghribī's ''Talkhīṣ al‐Majisṭī,'' he commentates on Ptolemy's Almagest, presenting his own observations and hypothesizes in addition with it. For instance, al-Maghribī supposed that the

precession Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In oth ...

would only occur in a motion that was uniform and continuous at a rate that was 1° for ever 66 years from his systematic stellar observations.

Works

Astronomy

His known works on astronomy include: * ''Tasṭīḥ al‐asṭurlāb'': a description of the construction and use of the astrolabe. * ''Maqāla fī istikhrāj taʿdīl al‐nahār wa saʿat al‐mashriq wa‐ʾl‐dāʾir min al‐falak bi‐ṭarīq al‐handasa'': a description of the geometrical methods used to determine the meridian line, the rising amplitude, and the revolution of the sphere. * ''Risālat al‐Khaṭā wa‐ʾl‐īghūr'': a chronological work on the Chinese and Uighur calendars, which was later translated from Arabic and Persian into Chinese. * Three zijes: ** ''Tāj al‐azyāj wa‐ghunyat al‐muḥtāj'' (The crown of astronomical handbooks), also known as ''Al‐muṣaḥḥaḥ bi‐adwār al‐anwār maʿa al‐raṣad wa‐ʾl‐iʿtibār''. ** ''Adwār al‐anwār madā al‐duhūr wa‐ʾl‐akwār'': contains results of the astronomical observations he carried out in Marāgha. ** ''ʿUmdat al‐ḥāsib wa‐ghunyat al‐ṭālib'' * Three commentaries on

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 Almagest: ** ''Talkhīṣ al‐Majisṭī'' (Compendium of the Almagest): based on his observations carried out between 1264 and 1275 CE. ** ''Khulāṣat al‐Majisṭī'' (Summary of the Almagest) ** ''Muqaddimāt tataʿallaq bi‐ḥarakāt al‐kawākib'' (Prolegomena on the motion of the stars): contains five geometric premises on the planetary motions in the Almagest.

Astrology

Ibn Abī al‐Shukr's astrological works were mainly devoted to horoscopes and planetary conjunctions used to tell the future.

Mathematics

Muhyi al-Din is most known for his works in

trigonometry Trigonometry () is a branch of mathematics that studies relationships between side lengths and angles of triangles. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies ...

, ''Book on the theorem of Menelaus'', ''Treatise on the calculation of sines''. He is also known for his commentaries on classic Greek mathematical works, in particular, his commentary on Book XV of '' Elements'' about measurements of the regular polyhedra. His writings on trigonometry "contain certain original elements".

References

{{DEFAULTSORT:Ibn Abi al-Shukr 1283 deaths Astronomers of Al-Andalus Astrologers of the medieval Islamic world Mathematicians of Al-Andalus 13th-century astronomers 13th-century astrologers 13th-century mathematicians 13th-century Al-Andalus people People from Córdoba, Spain Year of birth unknown 13th-century Iranian astronomers