In this treatise Aḥmad ibn Muḥammad ibn al‐Sarī, known as Ibn al-Ṣalāḥ, assesses a large number of errors in the manuscript tradition of Ptolemy’s star catalogue in Almagest VII–VIII. He discusses divergences in the positions of 88 stars that he found mostly in the different Arabic versions of Ptolemy’s Almagest, but also in later Arabic works such as al-Ṣūfī’s Kitāb Ṣuwar al-kawākib al-thābita (Book on Constellations) and al-Battānī’s Zīj, and he tries to trace the origin of these divergences. Because of Ibn al-Ṣalāḥ’s critical comparison of the important star catalogues available to him and especially of the different versions of the Arabic Almagest, Paul Kunitzsch emphasized the importance of this treatise for the study of the Arabic Ptolemaic tradition (Kunitzsch, esp. pp. 9–26).

Origin: Kunitzsch (p. 33) conjectures that Ibn al-Ṣalāḥ did not manage to finalise his treatise on the star catalogue, for example because of illness or his demise. This would suggest a date of compilation shortly before his death in 1154 ce. The only extant version of this text is, according to the colophon given in three of the four witnesses, this abridged version made by Quṭb al-Dīn al-Shīrāzī. Of particular importance is Istanbul, Topkapı, Ahmet III 3455 as it contains al-Shīrāzī’s autograph and was copied from an autograph by Ibn al-Ṣalāḥ.

Note Ibn al-Ṣalāḥ wrote a number of similar treatises on mistakes he found in the available versions of authoritative texts, for example Euclid’s Elements and Aristotle’s On the Heavens (for an overview, see Hullmeine).

Text: [ed. Kunitzsch]

[Introduction] (pp. 158–151) لمّا تأمّلت الجدال المثبت فيها مواضع الثوابت في الطول والعرض والجهة ومن أيّ قدر وصورة هي رأيت فيها خللًا ظاهرًا يشهد به ظاهر الحسّ فضلًا عن الرصد. — فإنّ أرسطوطاليس يقول في صدر كتابه فيما بعد الطبيعة وليس ينبغي أن نشكر من قال في الحقّ قولًا جزلًا بل ومن قال في ذلك قولًا نزرًا. [Commentary] (151–130) وها أنا مقبل على تعديد ما وقع فيه الغلط من الكواكب واحدًا واحدًا فمن ذلك الدبّ الأصغر. — وتصحيف من السدس إلى الستّة وهو في السريانيّ ونقل الحسن ك ي في ط وهو الصحيح. [al-Shīrāzī’s colophon] (p. 130) هذا آخر ما وجدنا من كلام أحمد بن محمّد بن السري على الثوابت وبخطّه. كتب هذه الفوائد المنسوبة إلى أحمد بن السري أحوج خلق الله إليه محمود بن مسعود بن المصلّح المتطبّب الشيرازي أصلح الله أعماله وللتجنّب عن الإطناب اختصر ألفاظه فليعلم والعذر عند كرام الناس مقبول.

Bibl.: SuterHeinrich Suter, Die Mathematiker und Astronomen der Araber und ihre Werke, Leipzig: Teubner, 1900, p. 120; KrauseMax Krause, ‘Stambuler Handschriften islamischer Mathematiker’, Quellen und Studien zur Geschichte der Mathematik, Astronomie und Physik, Abteilung B: Studien 3 (1936), pp. 437–532, p. 486; Carl Brockelmann, Geschichte der arabischen Litteratur. 2. den Supplementbänden angepasste Auflage, 2 vols + 3 suppl. vols, Leiden: Brill, 1943–1949, vol. I, p. 857; Paul Kunitzsch, Ibn aṣ-Ṣalāḥ. Zur Kritik der Koordinatenüberlieferung im Sternkatalog des Almagest. Arabischer Text nebst deutscher Übersetzung, Einleitung und Anhang, Göttingen: Vandenhoeck & Ruprecht, 1975; Paul Kunitzsch, ‘Arabic Criticism of Ancient Greek Traditions: Ibn al-Ṣalāḥ and the “Almagest”’, in Ahmad Y. al-Hassan, Ghada Karmi and Nizar Namnun (eds), Proceedings of the First International Symposium for the History of Arabic Science. April 5-12, 1976, Aleppo: University of Aleppo, Institute for the History of Arabic Science, 1978, vol. II, pp. 85–90; GAS VIFuat Sezgin, Geschichte des arabischen Schrifttums. Vol. VI: Astronomie bis ca. 430 H., Leiden: Brill, 1978, p. 92 (no. 24a); MAOSICBoris A. Rosenfeld and Ekmeleddin İhsanoğlu, Mathematicians, Astronomers, and other Scholars of Islamic Civilization and their Works (7th–19th c.), Istanbul: Research Centre for Islamic History, Art and Culture (IRCICA), 2003, pp. 177–178 (no. 458, A1); BEAThomas Hockey (ed.), The Biographical Encyclopedia of Astronomers, 2 vols, Dordrecht: Springer, 2007 article ‘Ibn al-Ṣalāḥ’ by Paul Kunitzsch; Paul Hullmeine, ‘Correcting Ptolemy and Aristotle. Ibn al-Ṣalāḥ on Mistakes in the Almagest, On the Heavens, and Posterior Analytics’, Arabic Sciences and Philosophy 32 (2022), pp. 201–246.

Ed.: Edition and German translation in Kunitzsch.