Contributed Talk - Splinter Historical

Friday, 25 September 2020, 16:20   (virtual room E)

The star catalog of Wilhelm IV, Landgraf of Hesse-Kassel

Andreas Schrimpf, Frank Verbunt
Philipps University Marburg, Radboud University Nijmegen, The Netherlands

Near the end of the 16th century Wilhelm IV, Landgraf of Hesse-Kassel, set up an observatory with the main goal to increase the accuracy of stellar positions primarily for calendar purposes. A new catalog was compiled from measurements of altitudes and angles between stars and a print ready version was prepared listing measurements as well as equatorial and ecliptic coordinates of stellar positions. Unfortunately, this catalog appeared in print not before 1666, long after the dissemination of Brahes catalog. With the help of a handbook for astronomers of the 16th century, written by Christoph Rothmann, the astronomer of the new observatory, and the data given in the manuscript we are able to analyze the accuracy of computations and measurements. We compare his remarkable accuracy with that of Brahe.