A nice 3D viewer that allows you to explore the Sun, a few moons and all the planets of our solar system in high resolution. The Great Red Spot on Jupiter, the beautiful rings of Saturn, the mysterious structures of the Pluto's surface, all of these can now be seen in great detail. This app is mainly designed for tablets, but it works fine on the modern phones too (Android 4 or newer).
-- you can zoom in, zoom out or rotate a planet, as you like
-- the auto-rotate function simulates the natural motion of planets
-- basic information for each celestial body (mass, gravity, size etc.)
-- the save function allows you to have any displayed image in your Gallery