One of the strengths of our collection is in the history of astronomy, and particularly an outstanding collection of the works of Johannes Kepler. So I’m very pleased to announce that we have just acquired the rarest work in Kepler’s bibliography, Ad Rerum Coelestium Amatores Universos … De Solis Deliquio. This slim volume documents an eclipse Kepler witnessed almost exactly 408 years ago, on October 12, 1605. Kepler observed the eclipse much the same way schoolchildren are taught today, using a pinhole camera which projected an image of the sun onto a sheet of paper. At just 16 pages, the work’s small size may have contributed to its low survival rate; Houghton’s copy is just the fourth known among the world’s libraries.
[John Overholt, Curator of the Donald and Mary Hyde Collection of Samuel Johnson and Early Modern Books and Manuscripts, contributed this post.]