CLAVIO, Christofero (1537-1612) - Astrolabium. Rome: Bartolomeo Grassi, 1593. Rare first edition of this treatise on the astrolabe divided into 3 books; the first focuses on practical geometry lemmas, the second treats the plot circles, projected on the plane of the astrolabe in stereographic projection. Finally, the third gives a result of rules or canons, to explain the various uses of the astrolabe, using ruler and compass. ""It is in this book we find the first glimpse of the multiplication method using circular functions, which received the name prostaphérèse"" (Houzeau-Lancaster). The edition contains nearly 400 woodcut diagrams representing sometimes complex structures and various tables including that of the sun places in the zodiac for the years 1600, 1601, 1602 and 1603. 3 parts in one volume, 4to (212 x 150mm). Large woodcut on title and numeours woodcuts and diagrams, woodcut initials and headpieces (without final black, occasional light browning and faint waterstaining). Contemporary blindstamped pigskin over wooden boards with original clasps, later paper labels on spine (large scuffing to back panel). Provenance: Monastery of Weingarten, Germany (ownership inscription on title dated 1602) - Königliche Handbibliothek (19th-century stamp on title used between 1810 and 1886). Adams C 2093; De Backer/ Sommervogel II, 1217; DSB III, p. 311; Houzeau/ Lancaster I, 3291. The lot is accompanied by an export license.