ʿAlī ibn ʿĪsā al-Asṭurlābī ( ar, علي بن عيسى, fl. 832) was a 9th century
Arab geographer and
astronomer. He wrote a
treatise on the
astrolabe
An astrolabe ( grc, ἀστρολάβος ; ar, ٱلأَسْطُرلاب ; persian, ستارهیاب ) is an ancient astronomical instrument that was a handheld model of the universe. Its various functions also make it an elaborate inclin ...
and was an opponent of
astrology. During the reign of
al-Ma'mun
Abu al-Abbas Abdallah ibn Harun al-Rashid ( ar, أبو العباس عبد الله بن هارون الرشيد, Abū al-ʿAbbās ʿAbd Allāh ibn Hārūn ar-Rashīd; 14 September 786 – 9 August 833), better known by his regnal name Al-Ma'mu ...
, and together with
Khālid ibn ʿAbd al‐Malik al‐Marwarrūdhī
Khālid ibn ʿAbd al‐Malik al‐Marwarrūdhī ( ar, خالد بن عبدالملك المرو الروذي) was a 9th-century Baghdadi astronomer.
In 827, Marwarrūdhī, together with the astronomer ʿAlī ibn ʿĪsā al-Asṭurlābī and a p ...
, he participated in an expedition to the Plain of
Sinjar to measure the length of a
degree
Degree may refer to:
As a unit of measurement
* Degree (angle), a unit of angle measurement
** Degree of geographical latitude
** Degree of geographical longitude
* Degree symbol (°), a notation used in science, engineering, and mathematics
...
. Differing reports state that they obtained a result of , 56 and two-thirds, or 56 and one-quarter miles per degree.
References
Sources
*
*
Further reading
* ʿAlī ibn ʿĪsā al-Asṭurlābī, Kitāb al-ʿamal bi-l-asṭurlāb , ed. by P. Louis Cheikho : "'Kitāb al-ʿamal bi-l-asṭurlāb li-ʿAlī ibn ʿĪsā", in: al-Mashriq 16 (1913), pp. 29–46; transl. German by Carl Schoy, "ʿAlī ibn ʿĪsā, Das Astrolab und sein Gebrauch", in: Isis 9 (1927), pp. 239–254.
{{DEFAULTSORT:Ali Ibn Isa
Geographers from the Abbasid Caliphate
Astronomers from the Abbasid Caliphate
9th-century astronomers
9th-century people from the Abbasid Caliphate
9th-century Arabs
Astronomers of the medieval Islamic world