Noctilucent clouds (NLC) is to some degree an unexplained phenomenon. They are seen at latitudes 55-65N during May-August (on an average every second clear night). It is known that NLC are water clouds sailing at heights of about 82 kms and they are visible because sun is shining at that height all night during summer months. However, it is not known for sure from where these very thin clouds do get their water to form. At this extreme height (and low pressure) atmosphere reaches its lowest temperature 130K just during the summer months thus creating the most favourable conditions for clouds to form.
These video samples are from 7 different NLC displays from 1999-2002. Each row represents one display.
Because of the huge distance of the clouds their real time motion is very slow and thus all clips are 100X speeded up (i.e. one hour display is compressed to 36 seconds). Huge distance is also a benefit: note in the clips on the first row, how there is a large scale rotation of the cloud structure.
This material is recorded either with Canon XL-1s or with Sony VX2000. Sony has better dark capabilities and actually after July 20th (when skies rapidly turn darker at my latitude 60N) it is the only MiniDV-camera that can be used to make quality recording.
To achieve reasonable picture quality MPG-files had to be used.
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| NLC01A (4.3 MB) | NLC01B (4.2 MB) |
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| NLC02A (4.5 MB) |
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| NLC03A (4.8 MB) | NLC03B (4.4 MB) | NLC03C (5.1 MB) | NLC03D (1.9 MB) |
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| NLC04A (1.8 MB) | NLC04B (1.7 MB) | NLC04C (1.9 MB) |
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| NLC05A (3.0 MB) | NLC05B (1.7 MB) | NLC05C (1.7 MB) |
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| NLC06A (2.0 MB) | NLC06B (1.5 MB) |
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| NLC07A (2.4 MB) |
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