'Ali ibn 'Isa al-Asturlabi

ʿAlī ibn ʿĪsā al-Asṭurlābī (Arabic: علي بن عيسى) was an Arab[1] astronomer and geographer of the 9th century. He wrote a treatise on the astrolabe and was an opponent of astrology. During the reign of al-Ma'mun, and together with Khālid ibn ʿAbd al‐Malik al‐Marwarrūdhī, he participated in an expion to the Plain of Sinjar to measure the length of a degree.[2] Differing reports state that they obtained a result of 56 miles (90 km), 56 and two-thirds, or 56 and one-quarter miles per degree.[3]

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  1. ^ H., Suter. "al-BADĪʿ al-ASṬURLĀBĪ". Brill. doi:10.1163/1573-3912_islam_sim_0993. {{cite journal}}: Cite journal requires |journal= (help)
  2. ^ Bolt 2007.
  3. ^ Raymond Mercier (2008). "Geodesy". In Helaine Selin (ed.). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Vol. 1. Springer. p. 966.