This is the last photo I took during my all-night vigil in the desert. The photo looks generally southwest, up towards the crest of the Sandstone Ridge.
My last battery gave out after the thirty minute exposure had finished, but before the camera had finished processing it. My speculation is that the odd purple fringing at the corners was caused by this interuption.
[This photo: 18mm in 35mm terms, about thirty minutes at f/4 and ISO 100, tripod mounted.]