Ptolemaeus - 99 km wide, 3 km deep
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Big smooth-floored Ptolemaeus is the top of this trio of craters. Although it has no central mountain, its floor does have numerous small craters. Below you can see the craters Alphonsus and Arzachel. They are younger steep-sided craters with tall central mountains. You can see the peaks of their mountains shining in the morning sun. Alphonsus is 3.2 km deep and Arzachel is 4 km deep. These three are found near the center of the moon.
Image: May 05, 2006