About fifty miles down the desolate Saline Valley road, one valley to the west of Death Valley, as the sun set, I stopped to camp for the night. I set up my camera with an external power supply, turned it to face roughly north, and let it rip while I slept.
There are 306 two-minute exposures in this sequence, for an elapsed exposure time of about ten hours. I started at 6PM and turned the camera off at 4:18AM, when cloud cover obscured the northern sky.
Processing the 306 exposures was more of an ordeal than shooting them. I ran them in a single stack using the Photoshop Statistic script—and after about three elapsed hours it crashed Photoshop. Clearing some space off my working hard drive helped, as did running the stack divided in three—with the pieces combined into a single image.
Exposure data: 10.5mm fisheye, 306 exposures, each exposure at two minutes, f/2.8, and ISO 320, exposures stacked using Photoshop Statistics set to Maximum; tripod mounted.