The Pseudo-Māshā’allāh treatise on how to construct and how to use an astrolabe was the most important text during the middle ages dealing with the most important astronomical instrument of the period. No critical edition has been published before the present one; and the existing printed versions are seriously deficient.
This critical edition presents the Latin text with critical apparatus on the construction of an astrolabe (22 chapters), of the star lists associated with the text, and also how to use the astrolabe (47 chapters) based on all known extant manuscripts (over 200 copies), along with diagrams and notes and comments, and a facing English translation. There is also an extensive introduction with information on the contents of the text, the manuscripts collated, Arabic terms and previously printed versions, as well as lists of lost manuscripts and erroneous ascriptions.
The edition has been published in two volumes: Introduction and the Compositio (volume1), and the Lists of Fixed Stars and the Practica (volume 2). There is also a “manual” edition containing a shortened introduction, the Latin text (which matches the Latin critical edition)and English translation with diagrams and notes for those who do not need the critical apparatus.
Ron B. Thomson, D.Phil. (Oxon) is a Fellow Emeritus of the Pontifical Institute of Mediaeval Studies in Toronto.