May 9, 2010
image by Yuri Goryachko, Mikhail Abgarian, Konstantin Morozov, Minsk, Belarus
With all the recent emphasis on data from lunar orbiters it might seem that little interesting can be seen from Earth. But this excerpt from a large mosaic by Yuri and the Astronominsk team dramatically demonstrates the utility and beauty of telescopic imaging. Here along the eastern shore of Mare Humorum are three sets of concentric curves that document the basin's dynamical story. Oldest is one of the best preserved sections of the Humorum Basin rim near bottom right. Although most of the mountainous edge is straight (the Kelvin Scarp), the feeling of curvature is reinforced by the structural elements near it. The three famous Hippalus Rilles mark where the edge of the crust bent and fractured. Why did this happen? Because the mass of the Humorum lavas to the left caused the center of the basin to sag, setting up strong bending stresses along the edges. The sinking also lowered the solidified lavas into a smaller volume, causing the mare materials to fracture and slide over previously adjacent parts, forming the wrinkle ridges. The near-terminator view shows a complexity to the ridges that can't be completely explained but does suggest how the ridges mark step-downs to the sunken center of the mare. None of this is new,, but it s beautifully shown.
April 24, 2010, 17:24-17:58UT, Maksutov-Cassegrain Santel D=230mm F=3000mm + Unibrain Fire-i 702 CCD b/w camera (IEEE-1394, 1388x1040) + Filter: Baader IR-pass 685nm+. Stacking in Avistack. Deconvolution in Astra
Rükl plate 52
Yesterday's LPOD: Yutu
Tomorrow's LPOD: No Stratton