Johann Bayer, a German lawyer and astronomer, died Mar. 7, 1625, at about age 52. In 1603, Bayer published a star atlas, the Uranometria, that is usually called, and properly so, the first modern star atlas. It contained 51 large star charts, one for each of the traditional 48 constellations, plus a map of the newly discovered southern constellations, and two planispheres of the northern and southern skies. The star positions were taken from the recent observations of Tycho Brahe, and they were carefully plotted onto grids that provide a backdrop for each plate.

To the non-astronomer, the most striking features of the plates are the attractive constellation figures. We display above the plates for Orion, Cetaurus, Cetus, Taurus, and Argo navis. To the astronomer, the atlas is significant because it introduced the practice of designating bright stars by letters of the Greek alphabet; alpha Centauri is a familiar example (second image), as is alpha Tauri (Aldebaran; fourth image), and beta Orionis (Rigel; first image).

We exhibited Bayer’s Uranometria in our exhibition, Out of this World: The Golden Age of the Celestial Atlas.

Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City. Comments or corrections are welcome; please direct to