Tangential Light

I saw a fascinating sunrise this morning. When I came out of the Rec-Fitness Center, the sun had just risen and thanks to a hazy cloud screen, I could see it perched there like a fat, red ball.

When I got over to the parking lot behind the physical plant, my view of the sun was blocked by the Music Center, but there was a white halo making a half-circle around the sun. It reminded me of days when you see sundogs off to either side, but if there were sundogs today, they were hidden by the trees. Instead, there was a bright beam extending vertically, and a bright crown at the apex of the circular halo.

It was less visible by the time I returned with the camera, and my photographic skills weren't up to capturing the sight as adequately as I'd like -- it was full day and much brighter than the photo above appears to be, but this allows you a better view of the halo and crown than some of my other attempts.

From checking out "sun dogs" on that fount of knowledge, Wikipedia, I'm guessing that this is an upper tangent arc, formed by the same sort of hexagonal ice crystals that create sun dogs, but seen when the sun is low. The site says that such arcs are relatively common, but seldom noticed because they are high overhead.

Sounds like a mini-parable right there.

You can see an illustration of tangent arcs at this atmospheric optics site.