Mimas is a moon of Saturn which was discovered in 1789 by William Herschel. With a diameter of 396 kilometres (246 mi) it is the smallest astronomical body that is known to be rounded in shape because of self-gravitation.
This amazing view of the moon with it’s most striking feature, Herschel Crater, was acquired at a distance of approximately 115,000 miles (185,000 kilometers) by the Cassini Orbiter.
Herschel Crater stretches 86 miles (139 kilometers) wide — almost one-third of the diameter of Mimas (246 miles or 396 kilometers) itself. If there were a crater of an equivalent scale on Earth (in relative size) it would be over 4,000 km (2,500 mi) in diameter, wider than Australia. Large impact craters can also be seen.