Awesome shot. Where was this taken?
Assuming that was directed at me, thanks, and I was at Lipan Point at the Grand Canyon. That's the far edge of the Canyon in the foreground. And, incidentally, that whiter band in the center of the frame that narrows toward the top...that's the zodiacal light -- sunlight reflected off dust in the plane of the ecliptic. That, and a bit of vignetting from the 400 f/2.8 shot wide open...one second at ISO 6,400, if I remember right, and with a 5DIII mounted to it.
I probably have one from earlier in the evening with Uranus and Mars in the frame, and I might have an interesting panorama from Wednesday night at the Snowbowl on the outskirts of Flagstaff. I also did some experiments with shooting Orion and the Big Dipper with the 35L as well as the Orion Nebula with the 400...but, to be honest, I haven't had a chance to review any of that, and all will require non-trivial post-processing. There's the panorama to assemble (including at least a few shots of it to cull from), and then all the exposures of the stars to first cull and then stack....