The picture was taken July 4th in the early morning @Averbode. This picture was made in RAW format with an exposure of 2s and ISO200. Editing using CS4 was done to show more details.
The clouds are the highest one on earth we currently know and are located between 76 en 85km altitude. They consist of tiny ice crystals and dust and can only be seen when the sun is below the horizon. Best observation is during the summer months and at latitudes between 50° - 70°.
