Sunlight is scattered by particles in the atmosphere (Rayleigh scattering). This effect is stronger for shorter wavelengths. That's why the sky is blue (the blue light is scattered sunlight) and why the sun looks yellow to red (the remaining light which was not scattered). This filtering effect becomes more intense if the way of the light through the atmosphere is longer, i.e. if the sun is close to horizon.
The display depicted below is caused by reddish sunlight which illuminates clouds from the bottom side.
Click on image or use the buttons to start a video or display a hi-resolution image.
|Date:||Dec 17, 2019 between 15:50 and 16:19 CET (=UTC+1h)|
|Instrument:||Sky surveillance camera pointing to west|
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