Shining Night Clouds

Last night before getting to bed I noticed the clouds were lit, a gorgeous view and I wondered what I was looking at.

On the tele I learned this morning about the phenomen and took this picture from the screen... wish I'd pictured those Shining Night Clouds outdoors along the coast last night.

Found some info on this rare MidSummer treat:

Shining night clouds are no clouds as we know them. The clouds that determine our weather extend from the surface of the earth at an altitude of 12 to 18 kilometers. Shining night clouds however are at a height of 80 to 85 kilometers.

They are only visible if a number of specific conditions are met: Ofcourse the sky must be clear, otherwise we cannot see them from the earth. There must also be sufficient water vapor and dust in the atmosphere at that height. The dust often comes from old meteorites whose tiny particles are still floating in the atmosphere. It must also be cold in that air layer; colder than minus 90 degrees. Only then the water vapor freezes on the dust particles there and forms ice crystals. There must be also be a lot of wind in the atmosphere at that high altitude. That all results in  beautiful wave movements in those clouds, and the fianl and an important condition is: These dust particles with the ice crystals must be illuminated by the sun!
And that at a moment when the sun is not shining or not shining anymore... That's very early in the morning before sunrise or late at the night after sundown. All of this can actually happen only in the weeks around the longest day, because then the sun remains little below the horizon, from where its sunlight can reach onto those wavy clouds from deep below, and we can see those shining clouds well because it is nightdark around us.