November 26, 2013
My Best Manners - And Then Some
image by Damian Peach
This is a corner of Mare Tranquillitatis that I've looked at many times, but find some new things here to catch my interest. Most observers probably look at Arago as a pointer to its two domes, Alpha to the north and Beta to the west. But they are easy to overlook with this moderate Sun view, so Arago's long ridge from the crater rim to the its center is a site to see. It appears to be made of material slumped from the northern and northwestern rim, converging on a central peak. A wedge of the southeast exterior of the crater - opposite the ridge - appears not to be covered with ejecta. This could be because younger lava covered that area or perhaps Arago was an oblique impact and the peak to rim ridge is associated with that. I don't know how that might happen so this is called hand-waving or idle speculation. The wide-floored Manners crater near the south west corner is another area of interest because of the strong bands on its walls. Its northern rim is pierced by one of a clump of secondary craters, so Manners is older than whatever crater (Tycho?) launched the projectiles that made those pits. One more thing - take a look at the LRO image - Manners is a FFC - a floor-fractured crater. Finally, did you notice the small crater at upper left, closest to the rille? Look at its floor. It looks like a concentric crater, but its not on the list. In this case the LRO view has too high an illumination angle to confirm it. We need a high-res low-Sun view to see what it really is.
Sept 24, 2013. C14.
21st Century Atlas chart 7.
Yesterday's LPOD: Looking More Closely
Tomorrow's LPOD: A Giant Footprint