Profile in Confusion

image by Damian Peach

When I need an image for LPOD (every night!) I can always find an intriguing one at Damian Peach’s website, which may be the largest collection of high quality lunar images by any single observer. This one caught my eye for three reasons - I couldn’t identify the craters, the feature on the right is bizarre, and the entire scene is very dramatic! 73 km-wide Petermann is the flat-floored crater on the left, and 63 km-wide Cusanus is to the right; both are near the Moon’s northeast limb, between Mare Humboldtianum and the pole. The lighting in Damian’s image shows the arc-ed shadow cast by the west rim of Cusanus, but the east rim looks like a series of pointy mountains. Clamoring to find a vertical view of these craters I discovered that there is no good one from Lunar Orbiters but Clementine (below) provides an explanation. The east wall of Cusanus is cut by two or three later small craters whose western rims are low or missing. So in Damian’s image we are looking at cross-sections of impact craters. What a remarkable view!

Chuck Wood