Ali ibn Khalaf

Alī ibn Khalaf (Arabic: علي بن خلف الأندلسي) was an Andalusian astronomer[1] who belonged to the scientific circle of Ṣāʿid al- Andalusī.[2]

He devised, with help from al-Zarqali, the universal astrolabe.[3] Both Khalaf and al-Zarqali's design were included in the Libros del Saber (1227) of Alfonso X of Castile.[4]


  1. ^ Puig, Roser (2007). "ҁAlī ibn Khalaf: Abū al‐Ḥasan ibn Aḥmar al‐Ṣaydalānī". The Biographical Encyclopedia of Astronomers: 34–35. doi:10.1007/978-0-387-30400-7_36. ISBN 978-0-387-31022-0.
  2. ^ Calvo, Emilia (22 September 2017). "Some Features of the Old Castilian Alfonsine Translation of ʿAlī Ibn Khalaf's Treatise on the Lámina Universal". Medieval Encounters. 23 (1–5): 106–123. doi:10.1163/15700674-12342244.
  3. ^ David A. King, World-maps for finding the direction and distance to Mecca, (Brill, 1999), 330.
  4. ^ Koenraad Van Cleempoel. "The Migration of Instrumental Knowledge from Flanders to Spain," in: Silent Messengers: The Circulation of Material Objects of Knowledge in the Early Modern Low Countries, Sven Dupré and Christoph Herbert Lüthy (eds.), (Transaction Publishers, 2011), p. 76.