This is an image of Lady Boot Arch in the Alabama Hills, located between Lone Pine, California and Mount Whitney. I created the star trails using 49 captures, each capture shot using a 10.5mm digital fisheye for 4 minutes at f/5.6 and ISO 200. I stacked the exposures using the Photoshop Statistics script.
Obviously, my camera was not pointing north—if I had been, the star trails would have appeared circular.
To be able to expose for a combined time of a little more than three hours, I used a direct current adapter plugged into a portable Vagabond II power supply from Paul C Buff. This lithium battery-plus-sine-wave-inverter is intended to power studio strobes and is at sixteen pounds is a bit heavy for wandering around the Alabama Hills at night. But it’s great to know I’m not going to run out of power.
Some “secret sauce”: In a couple of the frames in the composite, I light painted the arch using my LED headlamp. Also, I was in position before it was fully dark, and the tripod did not move, so I was able to Photoshop in some of the arch color from twilight.