Aḥmad b. Muḥammad b. Kathīr al-Farghānī (d. after 247/861), an astronomer at the court of the ʿAbbāsid caliph al-Maʾmūn (r. 198-218/813-33), wrote an influential compendium of Ptolemy's Almagest in thirty chapters and a description of the construction of the astrolabe. Ibn al-Nadīm (d. c. 385/995), in his Kitāb al-fihrist (ed. Gustav Flügel, 2 vols., Leipzig 1871-2, esp. 1:279), mentions another book by al-Farghānī, on sundials. Only a fragment of his treatise on the seven climates survives (Cairo,