Tangential Arc

Last night while conducting an astronomy program, I saw a tangential arc. I was caught without a good camera and this cell phone photo failed to catch the full color of the 5-minute phenomenon. Also visible to my eye, but not well shown in this photo, was the 22-degree halo around the setting sun.

This is the second tangential arc I've seen. The last one was on Dec 2010 and was accompanied by a very faint circumzenithal arc:

jg