Zu Kepplers Conchoid-Konstruktion

The physical models introduced by Johannes Keppler into astronomy were not only much more accurate than their predecessors, they were innovative theoretically to such an extent that they stand quite alone. The conchoid construction he presented in his ”Astronomia Nova” (1609) seems to have almost escaped notice in the literature. A misguided and sometimes unwitting interpretation of Keppler’s physical astronomy as a precursor to Newton’s celestial mechanics has impeded any fair analysis of it. Keppler’s physics is a physics of phases and frequencies, as Newton’s is a physics of accelerations. The purpose of this paper is to outline the impact of Keppler’s conchoid construction. His dynamical approach which is a profoundly original filter bank construction has found recently an unexpected revelation in magnetic resonance tomography.