June 11, 2012
image by Dmitry Makolkin, Moscow, Russia
I like lunar limbs, and enjoy trying to identify craters seen increasingly in profile. This northern limb is from a huge mosaic compiled by Dmitry gives another chance to explore. I have labeled a few features, and Howard Eskildsen produced an earlier view with more craters labeled. I like seeing Nansen, a Copernicus-size crater that rarely appears in LPODs. From views like this Nansen looks to be a relatively fresh complex crater with central peaks, but looking at an overhead perspective I see that it is older and its floor partly covered with material that may have been pushed in by the formation of Houssay on its rim. Further along the limb to the east is Hayn, a crater that really is a relatively fresh complex crater. It is difficult to see it under high Sun because it is somewhat near the pole but it may have rays, and might be the source for the mysterious one that cuts across the Mare of the Humboldtianum Basin. A crater that definitely has rays is Thales, which has a zone of avoidance toward the northwest, demonstrating that it formed from an oblique impact. One thing I never noticed before is that the zone of avoidance is darker than the ray-covered terrain on either side. The darker triangular area is reminiscent of Palus Somni, a feature named solely because no ray crosses it.
See original mosaic.
Rükl plate 5
Dimitry's Moon gallery
Yesterday's LPOD: Painterly Ejecta
Tomorrow's LPOD: Goodbye, Ancient Newton?