'Alī ibn al-Ḥusayn Abū l-Qasim al-'Alawi Ashraf al-Sharif al-Husayni, ( ar, ابن الأعلم الشريف الحسيني), (died in

Baghdad Baghdad (; ar, بَغْدَاد , ) is the capital of Iraq and the second-largest city in the Arab world after Cairo. It is located on the Tigris near the ruins of the ancient city of Babylon and the Sassanid Persian capital of Ctesiphon ...

, 985), was a 10th-century Islamic astronomer and

astrologer Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Dif ...

. Little is known about Ibn al-A'lam's life, and his birth date has not been established by historians. He seems to have been one of the most prominent

astronomers 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, natural satellite, moons, comets and galaxy, g ...

of the 10th century, demonstrated by the impact he had on

Islamic Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God (or '' Allah'') as it was revealed to Muhammad, the mai ...

and Byzantine astronomy. He appears to have been active in Baghdad, working under the patronage of its

Buyid The Buyid dynasty ( fa, آل بویه, Āl-e Būya), also spelled Buwayhid ( ar, البويهية, Al-Buwayhiyyah), was a Shia Iranian dynasty of Daylamite origin, which mainly ruled over Iraq and central and southern Iran from 934 to 1062. Coupl ...

ruler,

'Adud al-Dawla Fannā (Panāh) Khusraw ( fa, پناه خسرو), better known by his laqab of ʿAḍud al-Dawla ( ar, عضد الدولة, "Pillar of the bbasidDynasty") (September 24, 936 – March 26, 983) was an emir of the Buyid dynasty, ruling from 9 ...

(978–983). His

Nisba The Arabic word nisba (; also transcribed as ''nisbah'' or ''nisbat'') may refer to: * Nisba, a suffix used to form adjectives in Arabic grammar, or the adjective resulting from this formation **comparatively, in Afro-Asiatic: see Afroasiatic_lang ...

"al-Alawi al-Sharif" indicates that he was a

Sharif Sharīf ( ar, شريف, 'noble', 'highborn'), also spelled shareef or sherif, feminine sharīfa (), plural ashrāf (), shurafāʾ (), or (in the Maghreb) shurfāʾ, is a title used to designate a person descended, or claiming to be descended, fr ...

and a descendant of Ja’far al-Tayyar. Ibn al-A'lam's main work, a

zīj A zij ( fa, زيج, zīj) is an Islamic astronomical book that tabulates parameters used for astronomical calculations of the positions of the Sun, Moon, stars, and planets. Etymology The name ''zij'' is derived from the Middle Persian term '' ...

, also known as "" or "", was named after his patron . The work is lost, but scholars have been able to reconstruct most of it from

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

Persian Persian may refer to: * People and things from Iran, historically called ''Persia'' in the English language ** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples ** Persian language, an Iranian language of the ...

, and

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

sources.

Ibn Yunus Abu al-Hasan 'Ali ibn 'Abd al-Rahman ibn Ahmad ibn Yunus al-Sadafi al-Misri (Arabic: ابن يونس; c. 950 – 1009) was an important Egyptians, Egyptian astronomer and Islamic mathematics, mathematician, whose works are noted for being ahead o ...

, the renowned 10th century

Egyptian Egyptian describes something of, from, or related to Egypt. Egyptian or Egyptians may refer to: Nations and ethnic groups * Egyptians, a national group in North Africa ** Egyptian culture, a complex and stable culture with thousands of years of ...

astronomer, was a contemporary to Ibn al-A'lam, whose work he praised and cited. After Ibn al-A'lam's death in 985, his influence remained for at least three centuries, as evidenced by the tables of 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 ...

which were largely based on his work and that of the Egyptian astronomer

References

{{DEFAULTSORT:Abu Al-Salt 985 deaths 10th-century Arab people Astronomers from the Abbasid Caliphate Astronomers of the medieval Islamic world Astrologers of the medieval Islamic world 10th-century astronomers Scholars under the Buyid dynasty 10th-century people from the Abbasid Caliphate