Joe wrote:
So it's probably not worthwhile setting up my 12".
Joe, Here's my updated (9-21) observing guide. I feel this is doable. http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090916LCR... (14 megs) Here's an info panel of relative size models of the ejecta curtain and Cabeus A1 at it brightest size and of the crater. They were done in Mathematica. http://members.csolutions.net/fisherka/astronote/observed/LCROSS/20090920Cra... My feeling is that where the plume is contrasted against a background of the sunlit lunar surface, it will not be visible. So, the relative sizes shown here should not be considered a useable guide. IMHO, essentially, a contrast effect will occur where the shadowed portion of Cabeus A1 as seen from Earth will disappear as the ejecta plume reaches an apparent brightness nearly equal to the surface brigthtness of the sunlit lunar regolith. The Feb. 28, 2008 LPOD reproduces a topographic color-coded NASA JPL south polar map. http://lpod.wikispaces.com/February+28,+2008 From this one can see that south polar mountains M1 and M3 rise about 6 kilometers from their surrounding terrain. When look at Tom Bash's high libration south polar image http://www.lpod.org/?m=20070106 - labeled at bottom), one can see how Cabeus A and Cabeus A1 sit near the foot of M1. Bash's image and the known height of M1 at about 6km gives me some sense of the vertical scale against which to imagine an LCROSS ejecta plume that is 5km high. The LCROSS lampshade model at its brightest is 5km tall, with 3km expected to appear above the target crater’s rim. At the extreme southwest lunar pole, length and width distances are distorted by foreshortening while the vertical dimension has almost no foreshortening. Gary wrote:
You may not be aware that areas of permanent shade on the lunar poles are colder than on the planet Pluto.
Gary, see the LRO early science release press conference of 9-17. The LRO Team reconfirmed that the permanently shadowed regions of the lunar south pole are the coldest places with the (dwarf) planetary solar system. http://www.youtube.com/profile?v=59aaOW33aqs&user=NASAtelevision Clear Skies and Happy Impact Imaging - Kurt