The most spectacular contribution of the book-maker’s art to 16th-century science

Petrus Apianus’s Astronomicum Caesareum

First edition of “the most luxurious and intrinsically beautiful scientific book that has ever been produced” (de Solla Price), in an extraordinary hand-coloured early issue, as attested by the letterpress cancel slip on f. K1r.

The author of this popular textbook in astronomy is Petrus Apianus, astronomer and professor of mathematics at Ingolstadt, and a veritable pioneer in the production of astronomical and geographical devices. Apianus’s work on the project began eight years before and the ‘Astronomicum Caesareum’, which was printed in his private press at Ingolstadt, is considered “the most spectacular contribution of the book-maker’s art to 16th-century science” (Gingerich).

The handbook is divided in two parts. The first (ll. B1–M3) includes 40 chapters with maps reproducing the position and the movement of celestial bodies. The second part describes the meteroscope, an instrument designed to solve problems in spherical trigonometry, and relates the sighting of five comets: “The Astronomicon is notable for Apian’s pioneer observations of comets (he describes the appearances and characteristics of five comets, including Halley’s) and his statement that comets point their tails away from the sun. Also important is his imaginative use of simple mechanical devices, particularly volvelles, to provide information on the position and movement of celestial bodies” (DSB).

The volvelles in the work are each placed within a frame reminiscent of an astrolabe, a contemporary device that modelled the movement of the heavens in two dimensions and enabled the calculation of time and place, and assisted with astrology. The first moveable woodcut, which represents the planispheric astrolabe, compresses both hemispheres onto one plate. According to the text, the plate depicts 1,033 stars, and was based on the first printed star charts published in 1515 by Albrecht Dürer.

The most spectacular of the volvelles, which are the work of the artist Michael Ostendorfer, are the dragon plates. These include the title-page and the double-page spread dragon and moon dials. The dragon dial can be used to calculate the nodes of the moon, the two points of intersection between the yearly path of the sun, and the plane of the lunar orbit, which produce eclipses. Dragons were associated with eclipses, which were believed to occur when their head or tail blocked the sun. The thirteen small dragons indicate different parts of the lunar cycle.

For the dissemination of calculating technology in a standardised and reproducible form, the appearance of “paper instruments” has been compared to nothing less than the advent of printing (Poulle).

“Some 35 copies of the Astronomicum Caesareum are known today. Fabulously expensive to produce and prohibitively expensive to buy, it was always a rare book. Nicholas Wotton reported in 1544 from the Diet of Speyer that Apian would give Henry VIII a copy, for otherwise the king would not be able to get hold of it; Edmund Halley tried in vain to obtain a copy” (Hebron).