1. Johannes Kepler T J Osler

2. Johannes Kepler (pronounced / ˈ k ɛ pl ɚ /) (December 27, 1571 – November 15, 1630) was a German mathematician, astronomer and astrologer, and key figure in the 17th century scientific revolution/ ˈ k ɛ pl ɚ /Germanmathematicianastronomerastrologer17th centuryscientific revolution

3. The Great Comet of 1577, which Kepler witnessed as a child, attracted the attention of astronomers across EuropeGreat Comet of 1577

4. In astronomy, Kepler's three laws of planetary motion are:astronomy "The orbit of every planet is an ellipse with the sun at a focus."orbitplanetellipsefocus "A line joining a planet and the sun sweeps out equal areas during equal intervals of time."[1]line[1] "The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit."squareorbital periodproportional cubesemi-major axis

6. Five Platonic Solids

9. Kepler's Platonic solid model of the Solar system from Mysterium Cosmographicum (1600)Platonic solidSolar system

10. Closeup of inner section of the model

11. A plate from Astronomiae Pars Optica, illustrating the structure of eyes

12. Diagram of the geocentric trajectory of Mars through several periods of retrograde motion.Astronomia nova, Chapter 1, (1609).geocentricretrograde motion

13. Karlova street in Old Town, Prague – house where Johannes Kepler lived

14. Geometrical harmonies in the perfect solids from Harmonices Mundi (1619)

15. The iconic frontispiece to the Rudolphine Tables celebrates the great astronomers of the past:Hipparchus, Ptolemy, Copernicus, and most prominently, Tycho Brahe See http://www.hps.cam.ac.uk/starry/ for details of above.HipparchusPtolemyCopernicusTycho Brahehttp://www.hps.cam.ac.uk/starry/

17. Kepler's horoscope for General WallensteinhoroscopeGeneral Wallenstein

18. The GDR stamp featuring Johannes Kepler.GDR

19. 10 euro Johannes Kepler silver coin