September 10, 2009
image by Sean Walker Manchester, NH.
How many oddities do you see in this image?
The craters, Atlas and Hercules in front and Endymion, the smooth-floored one near the terminator, don't count. Let's start with the obvious - the concentric rilles and dark halo craters that yank Atlas from the classification of normal complex crater into the more exclusive floor-fractured category. What else? Hmm. How about the mare ridge like feature down the middle of Endymion. Does this mean the floor material is lava? Probably - it is dark at full Moon. Ok, something else. Notice the small bright spot to the bottom right of Atlas. Clementine shows it to be a fresh oblique impact crater with a zone of avoidance (to the bottom right) just like Proclus. Sean's low Sun image reveals that the bright pit is at the south end of a little hill that casts a shadow. There is no sign of the "hill" on Clementine, but there is a dark, unrayed zone, in the same spot. Hmm. One final odd feature - notice the line of bright hills north of Hercules that extends toward Endymion? Is it real, or a chance alignment that our eyes and brains, at least mine, make more out of then is there? Clementine does show that there are little ridges and bright spots, but does not answer the question. What is your opinion (backed up by images)?
Sept 6, 2009. C-14 f/11, DMK21AU04.AS, Baader IR-pass filter; excerpt from a mosaic of 12 frames (3:56 and 4:10 UT).
Rükl plates 7, 14 & 15
An overhead view of Endymion.
Yesterday's LPOD: 9/9/9
Tomorrow's LPOD: Selenology 101