"22 Degree Halo" from the site you linked.
On another forum (Mtb'er) I got an answer of Lens Flare :-( Fortunately others seen it and yourself.
Most did'nt see at first. I noticed when I took a picture of stone looking up to wards the point.
In amongst this thread: There are more pictures I took.
http://www.singletrackworld.com/forum/read.php?f=2&i=3085866&t=3085866