The Austrian National Library houses a heavily annotated copy of the 1515 printed edition of the Almagest (shelfmark: 80.O.11 Alt Rara), once part of Georg Wilhelm von Hohendorff’s (1670–1719) library. The marginalia, including illustrations and diagrams, can be traced to sixteenth-century editions, translations, and commentaries on the Almagest. This article presents the first study of these annotations, highlighting two key aspects: (1) a comparative approach to the Latin editions, constructing a kind of synoptic Almagest, and (2) the reformulation of Ptolemy’s procedure for calculating chords into verbally expressed arithmetical rules. Although the annotator remains unidentified, evidence suggests a late sixteenth-century origin. If so, these notes provide a rare glimpse into the early post-Copernican assimilation of the Almagest, offering insights into evolving mathematical practices in early modern astronomy. An Appendix details the main marginalia of the first book and their sources.
Ivan Malara (Wed,) studied this question.