April 29, 2022
Originally published June 14, 2012
left image by Israel Tejera Falcón, Vecindario, Las Palmas, Canary Islands, Spain; right image from LROC WMS Image Map
Looking closely at Israel's nice mosaic of the area west of Clavius I noted something that I didn't understand. In this excerpt a little piece of the rim of Clavius is at upper right, and half of Blancanus is below it. The thing that caught my eye was the ridge crossing the floor of Scheiner. Only a few things normally occur on crater floors: central peak mountains and hills, subsequent impact craters, mounds of debris slumped off the crater walls, sometimes shoved out of the ways by a larger crater formed very nearby. The Scheiner ridge doeesn't seem to fit any of those categories. The overhead view from LRO isn't as dramatic as Israel's image but shows that the ridge extends all the way across the floor as a slightly curved chord rather than a diameter. Along the edges of the crater floor are relics of probable older craters - perhaps such craters extended across Scheiner's floor. Enough time passed that these earlier craters were eroded before the smooth material was deposited that fills the floor. Perhaps the ridge is the unburied remnant of random ridges from a crater covered earlier floor.
Celestron CPC XLT 11" + Celestron Ultima x2 barlow + Lumenera Skynyx 2-0M camera
Rükl plate 72
Yesterday's LPOD: First Results
Tomorrow's LPOD: Why the Rille Turned