September 29, 2013

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Almost Microgeology

image by George Tarsoudis, Greece

It used to be that there were professional astronomers and amateurs. But now, with this image and others that LPOD has featured recently, there is only excellent imaging, whether from a giant telescope, a backyard one or an orbiting camera. I am amazed to see a terrestrial image of this scale and quality. The dramatic lighting highlights the ejecta from Theophilus, with the smooth impact melt ponds just north of the crater's rim. Also very conspicuous is a small rille that looks like a twig with branches at the top end. This has been imaged before but it is more distinctive here.

The rille also crosses a circular rise that George proposes is a

megadome similar to the Valentine Dome. The dome (outlined in red) is undetectable in the image due to the distractions of Theophilus' ejecta, but using LRO QuickMap elevations George found that it is roughly 85 km wide and 300-400 m high. The existence of the dome may explain the location of the rille. Few rilles occur in this area, but a rille does cross the Valentine Dome so this may be a similar feature.

Chuck Wood

Technical Details
Sept 25, 2013, 00:38:33 UT. Telescope SkyWatcher 14 inch
@f/4.5, camera Unibrain Fire-i 785, filter red.

Related Links
21st Century Atlas chart 7.
George's website

Yesterday's LPOD: Extreme Makeover

Tomorrow's LPOD: A Bridge Too Far, an Observation Quite Good


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