BAYER, Johannes (1572-1625). Uranometria, omnium asterismorum continens schemata, nova methodo delineata, aeris laminis expressa. Augsburg: Christopher Mang, 1603.

First edition of the first accurate star atlas. Earlier star catalogues followed Ptolemy's Almagest in using verbal descriptions to describe the location of stars within the 48 northern constellations of classical astronomy, an awkward system that occasioned constant errors and misapprehensions. Bayer, a lawyer and amateur astronomer, was the first to identify the location of stars within a constellation by the use of Greek letters, assigning them by order of magnitude. This simple innovation greatly facilitated the identification of stars with the naked eye, just five or six years before the invention of the telescope. Bayer's stellar nomenclature is still in use today. Bayer used Brahe's recent observations for the northern sky, and included, in chart 49, twelve new southern constellations observed by the Dutch navigator Pieter Dirckzoon Keyzer and reported by Pedro de Medina. To simplify identification of the stars Bayer included in his typographic descriptions both the traditional star numerations within each constellation and the many names for the constellations employed since Ptolemy. The graceful figures of Mair's charts were based on those of Jacobo de Gheyn in Grotius' edition of the Syntagma arateorum (1600). Warner, pp. 18-19; Norman 142. Exhibited: "The Heavens Revealed," Chapin Library, Williams College, 2003.

Folio (350 x 235mm). Engraved title, 3 leaves preliminary text, 51 double-page engraved star maps by Alexander Mair, on guards throughout, letterpress descriptive text printed on rectos/versos of the maps, printer's woodcut device on colophon page, woodcut headpieces, initials and tailpiece. (Engraved title a little soiled and with marginal repairs, marginal tear to pl.43, pale marginal dampstain to about five last plates, a little toning and occasional paper weakness near guards.) Modern speckled calf to style. Provenance: Robert Wheeler Willson, [donated to:] – Harvard College Library (inkstamp and release stamp on title-page verso) – Albert E. Lownes, 1899-1976 (bookplate).