Icy Ring Around the Moon

It's cold and windy here in Indiana, but there's a faint 22° halo around the moon. As light passes through hexagonal ice prisms, no light leaves the prisms at an angle less than 22° making a distinct light/dark boundary with a radius of 22° radiating out from the moon.

This is only my second time seeing a lunar halo. I got much better photos compared to my first attempt last winter.

Instagram's HDR filter really brings out the contrast along the light boundary

Beefed up in Photoshop, the halo is still pretty faint

This is a pretty good visual approximation of what was actually in the sky, very faint but definitely visible

Another shot, auto contrast and color in Photoshop