Noctilucent clouds low on northeast horizon, amid pre-dawn twilight, July 6, 2011. Capella in upper right of frame. Taken with Canon 7D and 16-35mm Canon zoom lens at 24mm for 10 seconds at f/4 and ISO 400. Taken at 3:35 am. Latitude of 50.9° N.
Astronomy author and photographer Alan Dyer presents amazing sky sights
The Amazing Sky 