There is a new LCROSS site page to provide the general public with info. It was put up on 9-10 and may be a draft under construction. It recites the following: "Ref: Moon = 3476 km (dia.) = approximately 0.5 deg viewable from earth = 30 arc min. = 1800 arc seconds (scale ~1.93 km/arcsec., or 5.2 arc sec. for a 10km event size). Or, using trig, at 385k Km away from earth the 10Km impact event will be approximately 0.001488 deg. or, 5.36 arc sec. So, these two estimate techniques give close results. 10km will be about ¼ percent of the moon's dia. (for reference, pretty small, but if you slice the moons diameter up into 100 strips, you can get the idea). The brightness or magnitude of the event is of course dependant of what part you are talking about, but we estimate magnitude 6-9 for the best visible part and time." http://lcross.arc.nasa.gov/observation/amateur.htm Clear skies - Kurt