Ali ibn Isa al-Asturlabi

ʿAlī ibn ʿĪsā al-Asṭurlābī (, fl. 832) was a 9th century Arab geographer and astronomer. 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 expedition to the Plain of Sinjar to measure the length of a degree. Differing reports state that they obtained a result of , 56 and two-thirds, or 56 and one-quarter miles per degree.

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Further reading

• Ê¿AlÄ« ibn ʿĪsā al-Asá¹­urlābÄ«, Kitāb al-Ê¿amal bi-l-asá¹­urlāb, ed. by P. Louis Cheikho : "'Kitāb al-Ê¿amal bi-l-asá¹­urlāb li-Ê¿AlÄ« ibn ʿĪsā", in: al-Mashriq 16 (1913), pp. 29–46; transl. German by Carl Schoy, "Ê¿AlÄ« ibn ʿĪsā, Das Astrolab und sein Gebrauch", in: Isis 9 (1927), pp. 239–254.