November 30, 2020

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Little Hills and Little Illuminations

Originally published May 13, 2011 LPOD-May13-11.jpg
image by Maximilian Teodorescu

Even places seen before are exciting to see again, especially if noticing something not remembered. Max's wonderful low Sun view of Ptolemaeus reveals the famous saucers – shallow depressions that are pre-existing craters covered by ejecta from the formation of the Imbrium Basin. At the north end of the floor are striated ridges, furrows and secondary craters from young and bright Herschel. At the southeast corner of Ptolemy’s floor is something I don’t remember seeing before – a cluster of a dozen or so bright hills. The LRO WAC nearside shows that these are indeed a group of hills, but doesn’t shed any more light on their origin. Looking south to Alphonsus, the crater is mostly full of shadow except for the central peak and grazing illumination across the western floor. And also a roughly triangular patch south and east of the peak. This is the type of fleeting illumination that in the past may have been reported as a transient gas or fog.

Chuck Wood

Technical Details
March 12, 2011, 20:35-20:50 U.T. 12" SkyWatcher Newtonian @ F/20, 3x Barlow with extension tubes, DFK 21 AF04.AS, three region mosaic, 3000/5500 frames each region, Seeing 3-5/10. Processing: Registax 6 and Photoshop CS2.

Related Links
Rükl plate 44

Yesterday's LPOD: Cracker of a View

Tomorrow's LPOD: Colorful Roughnicity


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