The role of clocks in determining star positions at the Landgrave Wilhelm IV observatory in Hessen-Kassel between 1560 and 1589

September 13th, 14:00 – 15:00

Between 1585 and 1589 the Altanen Observatory of Wilhelm IV triangulated the position of 343 stars. The procedures are documented in detail in the observation journals, as well as in Christoph Rothman’s manuscript opus ’Observationes stellarum fixarum‘. Again and again three timekeepers made by Jost Bürgi are mentioned. This lecture describes exactly how these clocks were used in this surveying process, and examines their technology.

Karsten Gaulke


After studying History and the History of Science and Technology in Stuttgart. Dissertation, Observationes huius Novae Stellae: The relationship between observation and hypothesis in Keppler’s opus ‚De Stella Nova‘. Since 2003 Director and Chief Scientist at the ‚Astronomisch – Physikalischen Kabinett und Planetarium‘ Kassel. Focus within the timekeeping department: Research into the early astronomical clocks of Eberhard Baldewein and Jost Bürgi.