Check out the link below for a great shot of a FULL circular rainbow.
http://www.mountainlight.com/gallery...aa0791pic.html
Shot was taken by the late great Galen Rowell (died in plane crash 2003?), one of the worlds foremost SLR landscape/adventure photographers. For those interested on the subject search around his site for more amazing natural light images plus lots of articles to read on photography/light etc etc.
It goes without saying that Brocken Spectres are common when you spend so much time above the clouds. Am a climber who is lucky to have seen these amazing spectres twice with my feet firmly planted on the ground!!!!