Astronomicum Caesarium

Astronomicum Caesarium.

The Astronomicum Caesarium (“The Emperor’s Astronomy,” 1540) by Petrus Apianus is a monumental example of European book arts of the sixteenth century, and one of the most beautiful books ever produced.

The author and producer, Peter Bienewitz (1495–1552), was the son of a shoemaker. He took the name Apianus (Latin for “bee man,” more or less a translation of his German surname), while a student at the University of Leipzig. Apianus worked as a mathematician and cosmographer (and astrologer) in the employ of emperor Charles V (1500–1558), whom he may have tutored. The Astronomicum Caesarium was produced for the emperor in folio format (about 18 x 13 in.) in a limited edition (about forty copies survive but the original run might not have been much larger).

The book compiles examples of astronomical instruments, ingeniously presenting many as actual working examples constructed of stacked revolving paper disks (called volvelles). The instruments can be used to calculate the positions of stars and planets, an increasingly useful function in the early years of maritime globalism. According to Owen Gingerich at Atlas Coelestic, “The single most impressive page is folio [E4], the mechanism for the longitude of Mercury, which contains nine printed parts plus a complex hidden infrastructure to allow movement around four separate axes.”

Based on the prevaling Ptolemaic system (the author was a contemporary of Copernicus), the book presents some scientific advances, such as the observation that the tails of comets always point away from the sun and the recommendation that solor eclipses can be helpful in establishing longitude. It reflects Apianus’s pioneering work in astronomical and geographical instrumentation. But it is most notable as a brilliant example of book arts.

Although Apianus gets the press, I think that the artist, Michael Ostendorfer (ca. 1490–1549), deserves much of the credit for this work, as the gorgeous hand-painted woodcut images are an exceptional feature. Check out the following examples (the aspect ratios vary slightly because of conditions of photography and cropping), then view the video at the end. A pdf of the entire book can be downloaded here.