south to left image by Ricardo José Vaz Tolentino
Ricardo is becoming famous for his single frame shots of the Moon. Sometimes they are a little grainy but the chance capture of critical lighting sometimes reveals hard to see features. Do you see anything unusual here, south of Piccolomini on the south rim of the Nectaris Basin? Notice the large shadowed embayment at bottom left. This is Janssen, a large, multi-generation crater that has been suggested to possibly be a small basin. The curved ridge above Janssen (thick line in image at left) has been proposed as a possible exterior basin rim. It might be, but there isn't anything on the opposite of Janssen that matches it. If it isn't a ring then what is it? Nothing comes to mind. Another ridge that seems odd stretches from the east/bottom rim of Piccolomini down to Janssen. This isn't part of the rims of either Nectaris nor the putative Janssen basins. But it is the western side (dashed line) of an irregular trough that is radial to Nectaris. Other images show the east side to be a straight scarp (straight line). A final thing to note on this productive image is at top center. The narrow curved line maps the boundary between heavily pitted normal highland terrain and smooth plains. The latter were probably deposited as fluidized flows of ejecta from the formation of Nectaris. You will notice other nearby examples of this ejecta.

Chuck Wood
Technical Details
02/22/2011; 02:32:30 Local Time. SkyWatcher 12" DOB + Celestron Ultima 2 X Barlow + ORION StarShoot Solar System Color Imager II, just one frame.

Related Links
Vaz Tolentino Observatório Lunar


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