Rare Noctilucent clouds form on the northern horizon and their eerie bluish light is reflected in the waters of the Ninilchik River in this fantastic early morning display around 2:00 a.m. local time.
Noctilucent clouds are quite a mystery and under intense study. They are formed by ice crystals at an altitude of 50 miles. They are rarely seen below about 50 degrees latitude and get ther name from the fact that they glow at night - iterally "light at night". They don't really glow on their own though, it is just the fact that they are so high that they catch and reflect sunlight even though it might be dark on the ground. They are mostly a summer phenomenon and seen when the sun is just a few degrees below the horizon. How the water molocules get so high into the atmosphere is a big mystery. Perhaps it is from the bombardment of the Earth by small pieces of ice or comets from space.
The clouds are generally quite a bit brighter than the auroa, and although they occur near the same altitude, catching the two togeather has been a real challenge. My most successful attempt with the two togeather can be found on this page entitled "On the Edge of Darkness".
I used a home-built 6x7 medium-format camera equipped with a 75mm lens to capture this unusual display.