The spectacular way in which they form spurs a child's imagination, while the features that result are easily spotted in the most modest equipment. Anyone can look up at the full moon and identify its largest seas and craters. With a pair of binoculars, lunar mountain ridges, crater rims, and central peaks come into focus. He was accustomed to seeing a much larger phase. The moon holds craters, basins, mountains, rilles, and rays.
Simple craters are what most people think of when they visualize a crater.
They tend to be bowl-shaped with rounded or small, flat floors. Simple craters also have smooth rims that lack terraces. Complex craters have scalloped inner walls that formed when unconsolidated rock slumped into the crater. Larger still are the so-called impact basins. An interior ring characterizes this crater form, which has three divisions of its own.