Mercurius in sole visus Gedani, anno christiano M DC LXI, d. III Maii, st. n. Cum aliis quibusdam rerum coelestium observationibus, rarisque phaenomenis. Cui annexa est, Venus in sole pariter visa, anno 1639, d. 24 nov. st. v. Liverpoliae, a Jeremia Horroxio: nunc primum edita, notisque illustrata. Quibus accedit succincta historiola, novae illius, ac mirae stellae in collo Ceti, certis anni temporibus clarè admodùm affulgentis, rursùs omninò evanescentis. Nec non genuina delineatio paraselenarum; & pareliorum quorundam rarissimorum

Danzig: Autoris typis, et sumptibus, imprimebat Simon Reiniger, 1662. FIRST EDITION. Hardcover. Fine. Bound in 18th c. quarter leather and mottled boards. A fine, untrimmed copy with deckled edges throughout. Occasional minor smudges. Engraved allegorical title vignette after A. Boy, 10 engraved plates by Hevelius, letterpress tables, woodcut and type-ornament head- and tail-pieces and initials. First edition of one of Hevelius’s most important publications; privately printed. It contains important telescopic observations of the planets Venus and Mercury, the only planets whose transits across the face of the Sun can be observed from Earth.

(truncated) The book opens with Hevelius’s classic description of his observation of the transit of Mercury, in 1661. “The work also contains the description by Jeremiah Horrocks of the transit of Venus on November 24, 1639, published here posthumously [and for the first time] as supplied by Huygens.  At the end is Hevelius’ announcement of the discovery of the variable star o Ceti (which Hevelius dubbed Mira), for which he has calculated ephemerides, and observations by Hevelius carried on between 1638-1662.”–Johannes Hevelius (B.Y.U., 1971), 7. Among the other observations published here is a description of optical atmospheric phenomena, including a paraselene (or mock moon), and a parhelion (or mock sun).

Hevelius was only the third person, after Gassendi in 1631 and Shakerley in 1651, to observe a transit of Venus with a telescope. The book was printed on Hevelius’ own private press, housed in his home observatory in Danzig, where he made his observations. While Hevelius employed professional printers, he engraved the illustrated plates himself, carefully copying the drawings that he had made during his observations. To record the transit, Hevelius outfitted his telescope with an apparatus that projected the image of the Sun and Mercury onto a sheet of paper in a darkened room.

Jeremiah Horrocks and the Transit of Venus:

Horrocks’ observation of the transit of Venus, the first ever made, is found on pp. 111-45; This was the first of any of Horrock's manuscripts to be published. Hevelius has added numerous annotations to the text.

Horrocks 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. (Inventory #: 5224)