Reference Work Entry

The Biographical Encyclopedia of Astronomers

pp 1059-1059

Sijzī: Abū Saҁīd Aḥmad ibn Muḥammad ibn ҁAbd al‐Jalīl al‐Sijzī

  • Glen van Brummelen

BornSijistān, (Iran), circa945


Sijzī, well known for his contributions to geometry, was also a prolific astrologer and astronomer. We possess few details of his life; his name suggests that he was born in Sijistān. His father, Abū al‐Ḥūsayn Muḥammad ibn ҁAbd al‐Jalīl, was also a mathematician and astronomer. Parts of Sijzī's life were spent in Sijistān and Khurāsān. In Shīrāz in 969/970, he was present (with Kūhī, Būzjānī, and others) for the famous observations of meridian transits of the Sun conducted by ҁAbd al‐Raḥmān al‐Ṣūfī. Later in life he became a friend of Bīrūnī, who often quoted Sijzī's results in his own works.

Of approximately 20 astrological and astronomical treatises composed by Sijzī, many were compilations and summaries of the works of others, enhanced and systematized by the addition of tables and commentary. His Jāmiҁal‐Shāhī contains 13 astrological works, three of which are summaries of treatises by Abū Ma ...

This is an excerpt from the content