On our way to Kelowna we got detoured around a mudslide near Banff a few weeks back and so re-routed south towards the Crowsnest area of southern Alberta along highway 22 near Pincher Creek. A few large thunderstorms had moved through about an hour previous and so the air was washed clean. I pulled over and we jumped out of the car. The boys couldn’t believe the stars. I set up my camera on a tripod and set the shutter for a long time exposure. Cars driving along the highway were lighting up the grass nicely and helped to balance the foreground and the sky. So amazing to see creation in all it’s splendour!! I believe the green is very faint northern lights illuminating some super high (noctilucent?) clouds. The cloud along the horizon is one of the large thunderstorms moving east over the lights of Lethbridge.
UPDATE – Sept 15:
I found this on Spaceweather.com earlier today which is likely a better description of the green sky:
“Although airglow resembles the aurora borealis, its underlying physics is different. Airglow is caused by an assortment of chemical reactions in the upper atmosphere. During the day, ultraviolet radiation from the sun ionizes atoms and breaks apart molecules. At night, the atoms and molecules recombine, emitting photons as they return to normal. This process produces an aurora-like glow visible on very dark nights.”
[Olympus E-M5, Olympus M.Zuiko 12mm f/2.0]