Hyginus (crater)

Hyginus is a small lunar caldera located at the east end of the Sinus Medii. Its rim is split by a long, linear rille Rima Hyginus that branches to the northwest and to the east-southeast for a total length of 220 kilometers. The crater is deeper than the rille, and lies at the bend where they intersect. Together the crater Hyginus and Rima Hyginus form a distinctive and prominent feature in an otherwise flat surface. Smaller craterlets can also be discerned along the length of this rille, possibly caused by a collapse of an underlying structure.

Hyginus is one of the few craters on the Moon that was not created as a result of an impact, and is instead believed to be volcanic in origin. It lacks the raised outer rim that is typical with impact craters.

Hyginus was also considered a possible landing site during the Apollo Program, because it was thought to possibly be a site of active volcanism.