Fine example of Bayer's map of the constellation Orion, one of the 48 constellations listed by the 2nd century astronomer Ptolemy, which remains one of the 88 modern constellations defined by the International Astronomical Union.
The map includes extensive manuscript annotations in an early hand.
The plate was originally included in the forty-eight maps of the individual constellations in Bayer's Uranometria in 1603. This is from the first reissue, without text on verso. The stars are identified by letters, Greek for the brightest, Roman for the fainter, with the order of the alphabets corresponding to decreasing brightness of the stars. Although a similar scheme had been introduced by Piccolomini (1540), it was Bayer's scheme that became universally accepted. Bayer based his constellation figures on the work of Jacobo de Gheyn and included stars from Ptolemy as well as the recent observations of Tycho Brahe and Keyser.
The atlas was also the first to represent the stars of the southern latitudes and based on observations which can be traced to an actual voyage of discovery-that of Houtman's first voyage to the East Indies in 1595-97.
According to Elly Dekker, the Uranometria substantially influenced Schiller's Coelum Stellatum and Kepler's Tabulae Rudolphinae. The work contains 49 charts of constellations, many expressed as familiar mythological figures and two charts of the northern and southern hemispheres. Bayer estimated the magnitude of each star, from first to sixth magnitude and initiated the method of distinguishing the stars in each constellation by Greek letters-a practice still in use by astronomers today. Art historians acclaim Bayer's work for the beauty of figure design and the quality of the engraving. Historians of science are still bringing to light its influence on later developments in celestial cartography. Publication of the Uranometria virtually shaped the way the heavens would be perceived for more than two centuries.