August 14, 2004

A Rip Across Tranquillity

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Image Credit: Mike Wirths

A Rip Across Tranquillity WOW! This is a wonderfully provocative image because of the features it shows and the others it suggests! The Cauchy area is remarkable for its near parallel fault scarp and rille, and for its two or three big domes. But even more delicate features appear with very low lighting. The white scarp face slashes across the terminator, clearly higher (and brighter) than adjacent mare. Near the bottom right, like a massive mountain is the flank of the well-known Cauchy Tau dome. On the far left is another classic dome, with no Greek letter, that is flat-topped with a rimless pit. Seven other possible domes are numbered in the mouseover, with #7 having an off center and elongated collapse pit. A number of other rimless pits are visible (arrows) and the one near dome #7 could mark a very low dome. Another furtive dome could be centered on the short linear depression (line) at the west end of the Cauchy Scarp. Similar pits and linear vents often occur at the summits of low volcanic domes in Idaho. A remarkably delicate rille-like depression near dome #2 is reminiscent of Elger's Rille near the Straight Wall. This rille can be seen in the bottom left of the Apollo 8 oblique shot if you look carefully! A final observation is that the right side of the image appears lower than the left, with the change of level occurring along a rounded scarp (white line with tick marks) that crosses the image diagonally. Near where this "scarp" crosses the Cauchy Scarp the scarp has an offset. Extreme grazing illumination images such as this are the best way to discover and map domes and other low relief features. Lets have a lot more wonderful images! — Chuck Wood Technical Details: Aug 5th/04 5:16am EDT, seeing 5-6/10.  18" Starmaster dob, ATIK-1HS II B&W webcam, 3X's Televue barlow, done in Registax 2 and Images Plus, Stack of 118 out of 600 Related Links: Lunar Orbiter IV View LO IV View - USGS ALPO Domes on GLR Map GLR Drawings/Images Rukl 36 Tomorrow's LPOD: Flammarion x 2

Author & Editor: Charles A. Wood Technical Consultant: Anthony Ayiomamitis A service of: ObservingTheSky.Org Visit these other PODs: Astronomy | Mars | Earth

 

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