The Northern Lights dance over the sweeping Red Deer River and Badlands of southern Alberta, from Orkney Viewpoint looking north over the valley. The Bleriot Ferry crossing is in the distance at the lights. Cassiopeia is embedded in the purple curtains. The river reflects the aurora light. This is a stack of 4 x 15-second exposures for the ground to smooth noise, and one 15-second exposure for the sky, all with the 20mm Sigma lens at f/2.8 and Nikon D750 at ISO 3200. They were part of a 250-fr