January 7, 2004

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Petavius: Rilles & Volcanic Spots

Image Credit: KC Pau

Petavius: Rilles & Volcanic Spots

One of the most skillful lunar imagers is Hong Kong amateur KC Pau. His picture of Petavius (Sept 11, 2003, 10" newtonian and Phillips Toucam) reveals details that I have never seen on any Earth-based photo, nor on the best Lunar Orbiter image! The 177 km wide Petavius is an older, degraded version of nearby Langrenus. The most fascinating feature of Petavius, apparently unique on the Moon, is the sharply defined rill that slices the crater floor, from the central peak to the southwest wall. Other rilles radiate away from the peaks, and two rille segments - shown to be continuous on a Lunar Orbiter image - cross the northeastern portion of the floor. Darkish, smooth spots are associated with the northern rilles, and a smooth spot at the southern end of the floor is now revealed for the first time to be associated with a shallow, pitted dome. Are the smooth patches volcanic pyroclastic (ash) deposits or mare lava flows? High Sun views show that the patches are as dark as mare lavas, but multi-spectral Clementine images show neither the blue of fresh mare material, nor the red of pyroclastics.

Related Links:
More KC Pau

Yesterday's LPOD: Gores of the Moon

Tomorrow's LPOD: The Right Stuff in Lunar Science

Author & Editor:
Charles A. Wood



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