Noctilucent Clouds from Cypress Hills Interprovincial Park, Alberta, July 15, 2013, visible at the start of the night but fading as the Sun set lower below the horizon. This is a single frame, the first, in a 123-frame time-lapse, taken with the 50mm lens at f/2 and Canon 5D MkII at ISO 800 for 15 seconds. Light from the setting waxing Moon illuminates the ground and sky.
The Amazing Sky 