Sphaera Emendata.

two important astronomical texts

Sammelband containing the first editions of two significant astronomical textbooks: an influential edition of Sacrobosco's De Sphaera with scholia by the Renaissance humanist Élie Vinet, supplement by Giovan Pietro Pierio Valeriano, and treatise on climates by Pedro Nuñez; and Caspar Peucer's Elementa Doctrinae de Circulis Coelestibus. Unsophisticated in contemporary vellum.

The Tractatus de Sphaera was the most important astronomy textbook of the medieval and early modern period. Composed around 1230 by Johannes de Sacrobosco, a scholar at the University of Paris, it circulated in manuscript for over two centuries, becoming in 1472 one of the first scientific books to be printed. By the early 17th century, right up to the time of Newton, more than two hundred editions had been published.

Sacrobosco is here 'mainly concerned with the circles on the sphere – the equator, the tropics of Cancer and Capricorn, the ecliptic, the meridian and horizon. It is often said that the book is a simple version of Ptolemy's Almagest (140 C.E.), but there very little of what we call Ptolemaic astronomy in it – a single mention of epicycles and deferents, with no indication of how to use them to predict planetary motion' (Ashworth, 'Johannes de Sacrobosco', Linda Hall Library). Of particular importance for the history of science, Sacrobosco argues 'every which way from Sunday that the Earth is a sphere' and his figure for the Earth's circumference, 25,000 miles, comes close to the modern calculation (Ashworth).

Caspar Peucer (1525-1602) was a student and son-in-law of Melanchthon who became a leading mathematician, and astronomer at the University of Wittenburg, as well as advisor and physician to the Elector of Saxony. His Elementa Doctrinae was a basic textbook on spherical astronomy that took the geocentric position. It was successful, being republished several times.

First editions; 8vo; volume I with woodcut publisher's device to the title and woodcuts throughout the text, volume II with woodcut publisher's device, woodcuts throughout, and 6 folding tables, contemporary manuscript note to the front blank, light spotting throughout, mild dampstain affecting the lower margins of some leaves at the rear, head of the 6th folding table cleanly cut away and loosely inserted, some adhesive and spots and paper remnants to the centers of the volvelles in volume I, none of which are complete, contemporary vellum, title to spine gilt on vellum label, red speckled edges, label partially lacking, ends of spines worn with damage to the endcaps, very good condition.