Chuck, As to the Utah observing altitude, the nominal impact position is with the Moon over the Keck in HI. So, you're looking at 20 degs off the Utah southwest horizon. However, the MMT Observatory on Mt. Hopkins in Arizona and Gemini South in Chile are secondary participating telecopes. If HI is weather socked out, the LCROSS team may slip the impact time forward and use scopes on Utah's longitude as the primary spectroscopy data gatherers. (Don't count too much on this one; my impression is the LCROSS team is really set on using the Keck and IRTF.) As to lunar phase, once the target crater is selected finally, the impact will be timed so the crater is just inside the dark side of the terminator. This is necessary to have the impact plume rise up 10 kilometers into the sunlight where the sun's energy will generate enough of a spectroscopic signature in the dust to be gathered on Earth. But the illuminated plume also has to be framed against the dark background of the night sky behind the Moon. If the plume rises within bright side of the terminator, the spectroscopic signal gets washed out. MIssion parameters allow the impact anytime between lunar disk illuminated fractions of 37% to 93%, but again, with the target crater just inside the terminator. Various amateur (and one by the LCROSS team investigator) of the likely target sites between these illuminations can be found here: http://groups.google.com/group/lcross_observation/web/index-to-images and at Jim Mosher's informal LCROSS wiki pages: http://ltvt.wikispaces.com/LCROSS http://ltvt.wikispaces.com/LCROSS#toc5 The LCROSS team lead astronomer has time reserved on the IRTF on July 1 for northern lunar hemisphere observing. This has not been announced for amateur concurrent imaging (as occurred in Dec. and Jan.). But Jim's wiki page on the training session will give you some impressions of the illumination involved at impact: http://ltvt.wikispaces.com/LCROSS+Jul+2009+Campaign The only thing that firmed up in the last six months is that the current launch dates necessarily imply an impact at the southern polar region, not the north. Clear Skies - Kurt Participating observatories http://www.nasa.gov/centers/ames/news/releases/2009/09-09AR.html Informal LCROSS Faq, questions 15 (lighting conditions) and 10 (participating observatories) http://groups.google.com/group/lcross_observation/web/lcross-faq