The Planispherium (Greek: Ἅπλωσις ἐπιφανείας σφαίρας, ‘Simplification of the Sphere’, a title attested in the tenth-century Suidas, see Sidoli/Berggren, 37 n. 1; Arabic: Kitāb Tasṭīḥ basīṭ al-kura, ‘Book of the Projection of the Surface of the Sphere’) deals with the projection of the celestial circles onto a plane. The text is lost in Greek but survives in Arabic, in an anonymous translation probably made in the ninth century (A.6.1), and in two Latin translations, by Hermann of Carinthia in 1143 (A.6.1) and by Isaac Hebreus in 1518 (A.6.2), both of which ultimately derive from the Arabic.

Bibl. J.-B.-J. Delambre, Histoire de l’astronomie ancienne, Paris, 1817, II, 433-457; M. Steinschneider, Die hebraeischen Uebersetzungen des Mittelalters und die Juden als Dolmetscher. Ein Beitrag zur Literaturgeschichte des Mittelalters, Berlin, 1893, II, 532-534; J. L. Heiberg, Claudii Ptolemaei opera quae exstant omnia, II: Opera astronomica minora, Leipzig, 1907, xii-xiv and clxxx-clxxxvi; F. Sezgin, Geschichte des arabischen Schrifttums, V: Mathematik, Leiden, 1974, 170 (no. 1), and VI: Astronomie, Leiden, 1978, 95 (no. III); O. Neugebauer, A History of Ancient Mathematical Astronomy, Berlin-New York, 1975, II, 857-879; P. Kunitzsch, Glossar der arabischen Fachausdrücke in der mittelalterlichen europäischen Astrolabliteratur, Göttingen, 1983 (Nachrichten der Akademie der Wissenschaften in Göttingen, I: Philologisch-Historische Klasse 11 (1982), 459-571), 484-485; C. Anagnostakis, The Arabic Version of Ptolemy’s Planisphaerium, PhD dissertation, Yale University, 1984; J. L. Berggren, ‘Ptolemy’s Maps of the Earth and the Heavens: A New Interpretation’, Archive for History of Exact Sciences 43 (1991), 133-144; R. Sinisgalli, S. Vastola, Il planisfero di Tolomeo, Firenze, 1992; P. Kunitzsch, ‘The Second Arabic Manuscript of Ptolemy’s Planisphaerium’, Zeitschrift für Geschichte der Arabisch-Islamischen Wissenschaften 9 (1994), 83-89 (reprinted in P. Kunitzsch, Stars and Numbers. Astronomy and Mathematics in the Medieval Arab and Western Worlds, Aldershot, 2004, VI); P. Kunitzsch, R. Lorch, Maslama’s Notes on Ptolemy’s Planisphaerium and Related Texts, München, 1994; R. Lorch, ‘Ptolemy and Maslama on the Transformation of Circles into Circles in Stereographic Projection’, Archive for History of Exact Sciences 49 (1995), 271-284; P. Kunitzsch, ‘The Role of al-Andalus in the Transmission of Ptolemy’s Planisphaerium and Almagest’, Zeitschrift für Geschichte der Arabisch-Islamischen Wissenschaften 10 (1995-96), 147-155 (reprinted in P. Kunitzsch, Stars and Numbers. Astronomy and Mathematics in the Medieval Arab and Western Worlds, Aldershot, 2004, VII); N. Sidoli, Ptolemy’s Mathematical Approach: Applied Mathematics in the Second Century, PhD dissertation, University of Toronto, 2004, 211-229; N. Sidoli, J. L. Berggren, ‘The Arabic Version of Ptolemy’s Planisphere or Flattening the Surface of the Sphere: Text, Translation, Commentary’, SCIAMVS 8 (2007), 37-144; O. Pedersen, A Survey of the Almagest. With Annotation and New Commentary by Alexander Jones, New York-Dordrecht, 2011 (first edition 1974), 405; C. Tolsa, Claudius Ptolemy and Self-Promotion. A Study on Ptolemy’s Intellectual Milieu in Roman Alexandria, PhD dissertation, Universitat de Barcelona, 2013, 245-246. See also A.6.1.

Modern ed. Critical edition of the Arabic text, together with an English translation, by Sidoli/Berggren. A facsimile of one of the two known Arabic MSS, together with an English translation, had previously been provided by Anagnostakis. For the Latin text, see A.6.1, A.6.2.