UPDATE Again (9/17): Rachael’s pic gets a kudos from UVa alumn, the Bad Astronomer.
I got a great twitter update from Nick in CVille saying that there was a Moon halo visible outside. So we went outside and, lo and behold, about 20 degrees* in radius around the Moon was a nearly complete halo! This means that there were some high altitude ice crystals that were refracting the light at just the right angle, as explained at Hyperphysics. So I go, “gee, maybe we should try and take a picture.” And Greg says, “I have a small camera tripod.” So two very, very amateur photographers played with the aperture settings on my camera (Canon PowerShot A540), and took the following (plus others of lesser quality):
The bright feature on the left stayed in place over the approximately 20 minutes we were out there. Is that a moon dog?
*How did I know it was approximately 20 degrees? Hold out a clenched fist at arms length. The width of your fist from index to pinky fingers is about 10 degrees. Your index finger alone is about one degree in width. Remember, bigger hands tend to correlate with longer arms, so you get it about right for people of all sizes!