Keplerсlockare a traditional clock with arrowsanddial.The difference is thata Kepler clock face isnot a circlebut an ellipsewith the numbers1, 2, 3 ... 12(I, II, III ... XII).Arrows (hour, minute and second) move in a circleuneven.
The length ofthe arrowsalso changeas they move. Arrowheadsdescribean ellipticaltrajectory.Additionallyon the dialdisplayssector, covering two adjacenthoursbetween whichat any given timeissecond hand. This sector ischanging itslocation and shape ofevery five seconds, but its arearemains constantaccording toKepler's second law. These watchescan hanginclassroomsmathematics,planetariums, observatories, museums ...
More about Kepler Clock Case 7: Earth and Satellite Or Kepler's clock