images from Mike Wirths, Lunar Orbiter IV and Clementine
In 1978 I searched all the Lunar Orbiter IV images and discovered most of the known concentric craters (CC). Recently I noticed another one on a SMART-1 image, and here is yet another previously unknown CC. This one was noticed on Mike Wirths’ spectacular mosaic of the rubbly area along the backside of the Alpes beyond Cassini. The CC occurs on thin debris from the Imbrium impact adjacent to smooth areas of lava near the craters Cassini E and D. In the discovery image the inner ring looks like a typical, but subdued CC donut. With the high resolution of Lunar Orbiter IV and Clementine the ring seems progressively more like mounds than a donut. And the narrow rille best seen in the Clementine view cuts through the floor of the CC. I think that this feature is a CC and hope that lower Sun angles from future releases of SMART-1 images will confirm it. The CC is about 7 km wide - perhaps it can be revealingly captured on large scale, high resolution amateur images.
Mike’s image: March 7, 2006. 18″ Starmaster + camera Lumenera Infinity 2-2 + 2.5X Powermate barlow + red filter.
Rükl charts 12 & 13
Yesterday's LPOD: Rima Weird
Tomorrow's LPOD: A Bend in the Middle