Deep-sky observation has been out of the question for weeks from my location on the Norwegian coast. This morning, however, I and my colleagues observed a very nice shallow-sky phenomenon that sometimes is seen from Scandinavia in connection with stormy weather.
The sun was some degrees below the horizon when I discovered the vividly luminescent nacreous clouds above the horizon in the south-east. Most striking was an 8 degrees long lenticular cloud about 20 degrees above the horison. The cloud was strongly iridiscent like mother-of-pearl. (The Norweigan term is perlemorsskyer: mother-of-pearl clouds).
Near the horizon were several smaller clouds, strongly coloured and nicely structured. In between were some delicate filaments, looking more like noctiucent clouds with a strange bluish colour.
The altitude of nacreous clouds is in the range 20.000 - 30.000 metres (up to 100.000 feet). They consist of very small crystals, and the iridiscence is caused by diffuse scattering of sunlight.
I can't provide a photo, but persons interested can search the web for images and more information about the phenomenon.
The sun was some degrees below the horizon when I discovered the vividly luminescent nacreous clouds above the horizon in the south-east. Most striking was an 8 degrees long lenticular cloud about 20 degrees above the horison. The cloud was strongly iridiscent like mother-of-pearl. (The Norweigan term is perlemorsskyer: mother-of-pearl clouds).
Near the horizon were several smaller clouds, strongly coloured and nicely structured. In between were some delicate filaments, looking more like noctiucent clouds with a strange bluish colour.
The altitude of nacreous clouds is in the range 20.000 - 30.000 metres (up to 100.000 feet). They consist of very small crystals, and the iridiscence is caused by diffuse scattering of sunlight.
I can't provide a photo, but persons interested can search the web for images and more information about the phenomenon.
