The world celebrates this year the 450th birthday of Johannes Kepler (1571-1630), whose planetary laws are based on the invariance of physical quantities as the angular momentum. Many scientists consider the formulation of the motion laws as the kick-off of modern physics. Kepler, however, owes his success largely to the precise observation instruments of the Swiss watchmaker Jost Bürgi (1552-1632), who is also considered as co-inventor of the logarithm. Their fruitful cooperation culminated around 1600, when both worked closely together with Tycho Brahe in Prague. Everybody today knows Kepler and Brahe, but only few know Bürgi, who did not master Latin, did not extensively publish and consequently fell off the grid of history of science.
The SPS helps that Bürgi finds the scientific recognition he deserves by co-organizing an annual symposium since 2016. This year the 5th international symposium will take place again as a two-day event, first with a full-day workshop on Bürgi's person, work and historical environment on Friday, 30.4.2021, and on the next day with a half-day forum, addressing future technologies. The venue is Bürgi's birthplace Lichtensteig in the Swiss canton St. Gallen, https://www.jostbuergi.com/
The thematic focus at the Friday workshop with four lectures is the 400th anniversary of the publication of Bürgi's 'Progresstabulen', i.e. the logarithms, which Bürgi constructed for his own use already in 1590, but published them only thirty years later. A careful analysis of the history of the logarithm shows that John Napier and Jost Bürgi are undoubtedly to be regarded as independent co-inventors of the logarithm.
B. Braunecker