International Space Station and the Milky Way in twilight

While taking a timelapse of the summer Milky Way my sequence caught the International Space Station flying over in the morning twilight.  Some clouds are moving in from the left and the Milky Way with the Tea Kettle of Sagittarius at the bottom, just about to set.  The Tohono O'Odham town of Sells is just below the Milky Way in this view from the 90 inch Bok Telescope's Bok Walk on Kitt Peak.  This image was taken with my 17-70mm Sigma lens at 17mm focal length and an exposure of 30 seconds at f/2.8, ISO 1600.