Reference Work Entry

The Biographical Encyclopedia of Astronomers

pp 557-558

Ibn ҁIrāq: Abū Naṣr Manṣūr ibn ҁAlī ibn ҁIrāq

  • J. Len Berggren

BornGīlān, (Iran), circa950

DiedGhazna, (Afghanistan), circa1036

Ibn ҁIrāq was an astronomer who also made important contributions to trigonometry. His name and contemporary references to him as “prince” (al‐amīr) suggest that he was a member of the Banū ҁIrāq dynasty, which ruled Khwārizm until the Ma'mūnī dynasty conquered it in 995.

Ibn ҁIrāq was a pupil of the famous scientist Abū al‐Wafā' al‐Būzjānī, and he, in turn, had a pupil who became one of medieval Islam's most famous scientists, Abū al‐Rayḥān al‐Bīrūnī. Among Abū Naṣr's works are a number of treatises answering questions posed by Bīrūnī.

At some point in the early 11th century—1016 has been suggested—both Ibn ҁIrāq and Bīrūnī joined the court of Maḥmūd of Ghazna, Afghanistan, where Ibn ҁIrāq passed the rest of his life.

Ibn ҁIrāq was a capable astronomer, and Bīrūnī praised his method for finding the solar apogee as one that was as far beyond the methods of the modern astronomers as their ...

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