Hipparchus - 155 km wide
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Hipparchus is an ancient and wrecked crater. It is more than 4 billion years old. Its floor is flooded by lava that came up through internal faults. It is home to many younger craters. Just to the south of Hipparchus is 139 km wide Albategnius. It is a bit younger than Hipparchus with 2 good-sized internal craters and a tall central peak. At the bottom of the photo you will see how the low angle of the sunlight formed an X where four small craters meet.
Image: July 13, 2005