Ibn al-A'lam
'Alī ibn al-Ḥusayn Abū l-Qasim al-'Alawi Ashraf al-Sharif al-Husayni, (Arabic: ابن الأعلم الشريف الحسيني), (died in Baghdad, 985), was a 10th-century Islamic astronomer and astrologer.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 of the 10th century, demonstrated by the impact he had on Islamic and Byzantine astronomy.He appears to have been active in Baghdad, working under the patronage of its Buyid ruler, 'Adud al-Dawla (978–983).The work is lost, but scholars have been able to reconstruct most of it from Arabic, Persian, and Greek sources.