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Night clouds or noctilucent clouds are tenuous cloud-like phenomena that are the "ragged-edge" of a much brighter and pervasive polar cloud layer called polar mesospheric clouds in the upper atmosphere, visible in a deep twilight. They are made of crystals of water ice. The name means roughly night shining in Latin. They are most commonly observed in the summer months at latitudes between 50° and 70° north and south of the equator. They can only be observed when the Sun is below the horizon. They are the highest clouds in the Earth's atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometres (47 to 53 mi). They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are in the Earth's shadow. Noctilucent clouds are not fully understood and are a recently-discovered meteorological phenomenon; there is no record of their observation before 1885. Noctilucent clouds can form only under very restrictive conditions; their occurrence can be used as a sensitive guide to changes in the upper atmosphere. They are a relatively recent classification. The occurrence of noctilucent clouds appears to be increasing in frequency, brightness and extent. It is theorized that this increase is connected to climate change. (Wikipedia - en.wikipedia.org/wiki/Noctilucent_cloud ) Panorama of 3 pictures. View large to see detail
It's been 1 year since I joined Flickr! It's been a wonderful year and I want to thank everybody for the views, favs , comments and invitations. I've met incredible photographers here who have been and continue to be great inspiration and motivation. Thank's all of you! This picture is taken during my vacation at lake Peipus ( the biggest trans-boundary lake in Europe, between Estonia and Russia) This morning didn't look promising, just very dark and cloudy. Suddenly this amazing light and color showed up at sunrise. I used long exposures and got to take only 2 pictures before the light was gone and the morning continued to be dark and cloudy. So this was the one that fulfilled my expectations.