April 15, 2006

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A Floorful of History

Image by David Dench

Deslandres (256 km diameter) is a large ancient impact structure whose floor has recorded much lunar history. The feature is ancient for its rim has been battered by Walter (in the 3 o’clock position), Lexell (6:00), Ball (7:30), and other unnamed craters. The floor contains one named crater, Hell at 9 o’clock, and many other craters, including the ghost of Hell immediately to its east. The ghost is just one of the older craters formed on an earlier floor of Deslandres and now mostly covered by later flows. The nature of this floor-covering material is uncertain. Because the floor doesn’t look dark at high sun it isn’t mare lavas. But as pointed out earlier its not obvious that the material is basin ejecta or lavas of some sort. But it is clear that some parts of the floors (Walter and two round spots to the west and a darkish area just inside Deslandres’ northern rim) are less rough and less cratered than the main floor. Multiple periods of floor covering have occurred at Deslandres, but we don’t know the details. And what is the source for the chain of 4-6 secondary craters at the 1:00 position?

Chuck Wood

Technical Details:
6 April, 2006. 16″ Dob + 600 TV line video surveillance camera

Related Links:
Rükl plates 64 & 65
David’s website
Another LPOD Deslandres

Yesterday's LPOD: Mystery Photo

Tomorrow's LPOD: Fold the Moon


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