HEVELIUS, Johann (1611-1687). Mercurius, in sole visus Gedani. Danzig: Simon Reiniger, 1662.

First edition, uncut, of the Polish astronomer's observations of the 3 May 1661 transit of Mercury, followed by the first published description of the 24 November 1639 transit of Venus by the short-lived English astronomer Jeremiah Horrocks. Horrocks (1618-1641) was the first astronomer to observe a transit (or conjunction with the sun) of Venus, an event that he had predicted through close study and correction of Kepler's tables. His observations enabled him to make the first accurate calculations of the diameter of Venus and of the constants of its orbit. This was the first of any of Horrock's manuscripts to be published. Hevelius was renowned not only as an astronomer but also as an instrument maker, and is perhaps best-known for his detailed maps of the Moon. His works are notably rare: a fire at his house in September 1679 destroyed all of his various works published up to and including 1679. RBH records only 4 copies at auction in the past fifty years. Norman 1067.

Folio (390 x 235mm). Uncut, ten engraved plates by Hevelius (occasional light spotting). Later half calf over paper-covered boards (a little rubbed, some chipping to extremities). Provenance: Librairie Thomas Scheler, Paris (bookseller's ticket on front pastedown) – penciled numbers in margins of a few leaves — Owen Gingerich (bookplate).