Celestial
Spheres
Explore Ptolemy, Copernicus, Tycho, and Kepler in an interactive 3D astronomy simulator, then observe the real sky, eclipses, retrograde motion, planetary moons, comets, and asteroids.
Explore Ptolemy, Copernicus, Tycho, and Kepler in an interactive 3D astronomy simulator, then observe the real sky, eclipses, retrograde motion, planetary moons, comets, and asteroids.