February 26, 2013

Ropes And Rice

image by Damian Peach, Selsey, UK

We usually see Grimaldi as a dark spotch near the western limb. Damian's magnificent near-terminator view
shows there are many fascinating details to savor. Most arresting to me is the wedge of terraces just inside
the opposite rim. I know that China has an active lunar exploration program; these terraces, minus the green
of rice, will make them feel at home. More prosaically, the terraces are an ejecta flow from the formation of
the Orientale Basin. The terracing is not visible on the higher Sun LRO QuickMap mosaic, once again dem-
onstrating the continuing value of telescopic low-Sun images. I wonder if these terraces are like ropes in
ropy lava, places where the slowing flow of material crumples as the snout cools and slows while the back part
is still moving forward? Skipping over most of the other interesting features take a look at the half-shadow filled
crater Damoiseau D near bottom left. Looking at the illuminated wall there is a bright rim top, with a lower dark
band - partially with a bright band within it - resting on another bright band. This looks like layering within the
crater's wall, but the QuickMap view reveals that this is an unusual concentric crater. The exact mapping of
bands in Damian's oblique view onto the overhead LRO image is an exercise left to the reader.

Chuck Wood

Technical Details
2012_12_26_1926ut.

Related Links
Rükl plate 39
21st Century Atlas chart 26.
Damian's webpage & Facebook page

Yesterday's LPOD: The Truth

Tomorrow's LPOD: Snow Moon

---