Noctilucent Clouds as seen from North Dakota on July 3, 1982. These clouds
are visible about an hour after sunset mostly in summer
(when the sun is about 12 degrees below the horizon). They are much higher
than normal clouds being about 50 miles up - they may be ice crystals
condensing on dust from meteors or other sources.
The bright star visible is Capella.
used with his permission.