January 19, 2018

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Originally published July 27, 2008 LPOD-July27-08.jpg
left image by Wes Higgins; right image by George Tarsoudis

Most things on the Moon are round because that is the shape of an impact crater. Linear features usually have other origins, but not always. In Wes' high resolution image of the crater Catharina there are number of linear features. One (labelled 1 in George's wider view) is a mostly straight line with a few wide spots. This is probably a secondary crater chain, an idea that is strongly supported by the fact that a line through it extends to the central peaks of Theophilus. Much shorter little crater chains (2) are at the bottom right of Wes' image just outside the crater Beaumont. Its harder to accurately extend a line through these short chains because they are in shadows on George's image, but they don't seem to extrapolate through the center of Theophilus, but rather appear to come from the general area of its south rim. This is more surprising if they are secondaries from Theo, which I am sure they are for there is no other nearby source. Linear number 3 looks gouge-like but if you look carefully you can see that it is made of overlapping, round-ended depressions. This is similar to some of the sculpture near Ptolemeaus that was made by closely space Imbrium ejecta with a strong horizontal component to its movement. Feature 3 points back to the center of Cyrillus, but it seems too wide to come from there. A line through feature 3 extends all the way to the Imbrium area so it is possible that it is a distant crater chain from that Moon-shaking impact.

Chuck Wood

Technical Details
Left image: 09/01/07. 18" Reflector,Infinity 2-1M camera, MAP-128x48, stack of 105 frames
Right image: 08/14/2006. LXD-75 8" SC, barlow 2.5X, DMK 21BF04

Related Links
Rükl plate 57

Yesterday's LPOD: What Technology is For

Tomorrow's LPOD: Pushing the Envelope


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