Ali ibn Sulayman al-Hashimi
Ali ibn Sulayman al-Hashimi, known as al-Hashimi, was a Muslim astronomer and mathematician who flourished in the late 9th century, around the year 890. Little is known about his life, but he is noted for his work with irrational numbers.
His only major work is Kitāb fīʿilal al‐zījāt (Book of the Reasons Behind Astronomical Tables), probably written in the late 9th century. The book discusses the astronomical ideas of Greek, Indian, and Persian sources and shows the development of Islamic astronomy before the Ptolemaic tradition. It covers the basic theories behind astronomical tables (zijes), as well as topics such as chronology, planetary cycles and equations, eclipses, timekeeping, and astrology.
The work is not well organized and contains technical errors by al-Hashimi and later copyists. It may have been copied in Damascus in 1288. Today it survives in a single manuscript at the Bodleian Library, Oxford (MS Arch. Selden. A.11). Although it offers no new ideas, the text is historically important because it cites 14 other astronomers, many of whom are lost, providing valuable insight into the history of science. It has been translated into English by Fuad I. Haddad and Edward Stewart Kennedy.
This page was last edited on 3 February 2026, at 04:53 (CET).