Flammarion x 2
This has been a great couple of weeks for lunar photography, with many skilled imagers acquiring wonderful pictures nearly every night of the lunation. Here is a recent pair of Flammarion, an often overlooked and slightly battered crater north of Ptolemaeus. Have you ever knowingly observed Flammarion? Named after Camille Flammarion the great popularizer of astronomy from the 1880s through the 1920s, this crater has been affected by many of the great events of lunar history. Like nearby Ptolemaeus, it was formed sometime before the formation of the Imbrium basin - this is demonstrated by three signatures of that huge impact. First the area around Flammarion is striated with linear ridges and valleys formed by flying ejecta. Second, large basin secondary craters (Mosting M and the one to its south - see mouseover) pelted the area. And third, the floors of Flammarion, Flammarion T and other old craters are veneered with Cayley Formation light plains - assumed to be Imbrium's fluidized ejecta. At some later time a narrow linear rille cut the Cayley along the north edge of Flammarion's floor, but the western end of the rille was subsequently buried by lavas from Sinus Medii. Time passed - maybe two billion years - with small craters forming here and there. Then, when the crater Herschel formed just south the this area, a few apparent secondary crater clusters and elongated pits cut into Flammarion's floor. And finally, so far, the young fresh crater Mosting A was created, spreading a faint nimbus of powdered rocks, visible under a high sun.
— Chuck Wood
Left image: Aug 7, 2004, -3h38, 24" Cassegrain, B&W webcam + infrared filter, 100 raw frames processed.
Right image: Aug 8, 2004, 9:41 -9:44 UT, TMB 8" F/9, Seeing 8/10
Lunar Orbiter IV View
Rukl Atlas of the Moon Sheet 44
Yesterday's LPOD: A Rip Across Tranquillity
Tomorrow's LPOD: Megadome