When I left my camp site the skies were completely clear. Just over an hour later I had arrived and was nearly finished setting up to shoot. I had scouted the location earlier in the day and knew the galactic core was aligned near perfectly with Grand Prismatic Spring. As I took my first few images, I noticed some clouds rolling in fast. Working fast (no such thing with long exposures), I started shooting my panorama. Within minutes, nearly the whole sky was blotted out. I decided to shoot a few really long exposures for star trails, and after a white noted that the clouds were thinning a bit. I shot a second panorama of the sky, hoping that between the two, I could get a clean shot of the sky. Many, many, hours of selective masking later, I achieved just that. This magical scene was captured at Yellowstone National Park in Wyoming.