Devils Island Lighthouse and Milky Way-Apostle Islands Print of the Year 2012
A framed print: 26″ x 21″ on archival cotton, $300 + ship/handle
Out of stock
The spectacular green banding seen in the Devils Island photo at first glance look like aurora borealis (northern lights), but in fact is something different. It's called banded air glow.
Even absent light from the stars or other celestial objects, the night sky is never completely dark. Earth's atmosphere itself glows faintly all the time as atoms of oxygen, having been excited during daytime hours by UV radiation from the sun, emit faint light as they drop back to their less energized state.
This photo was captured on July 20, 2012 at 12:20 am with a Canon 7D camera.
Specifics: 4 minute exposures (2 shots, telescope drive on, telescope drive off), ISO 2000, Canon 10-22mm lens operating at 10mm at f/4.
On the night we shot this photograph, this air glow display was unusually bright. To the unaided eye, it looks like a very thin cloud layer, and usually escapes notice altogether. Only with the exceptionally dark skies of the Lake Superior region and the long exposure capability of the camera did the color emerge. The banded structure is caused by atmospheric gravity waves, a common wave-like movement of air high in the thermosphere (more than 50 miles up).
Thanks to the National Park Service for their support: Bob Krumenaker, Superintendent