Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2013 March 29 Ringside with Rhea Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: Orbiting in the plane of Saturn's rings, Saturnian moons have a perpetual ringside view of the ..