Photographer Adrien Mauduit wrote from Denmark late last week (May 26, 2017):
I caught my first real and confirmed noctilucent clouds of the season last night. I shot the pictures on Ordrup Strand in the northwest of Sjælland from midnight to about 2 a.m. I used Canon 6D and Sony a7rII to take the shots, along with various lenses. One can see type I (patch) and II (bands), and I am waiting for more displays as the season goes on!
Noctilucent clouds form in the highest reaches of the atmosphere – the mesosphere – as much as 50 miles (80 km) above the Earth’s surface. They’re are thought to be made of ice crystals that form on fine dust particles from meteors. They can only form when temperatures are incredibly low and when there’s water available to form ice crystals.
Why do these clouds – which require such cold temperatures – form in the summer? It’s because of the dynamics of the atmosphere. You actually get the coldest temperatures of the year near the poles in summer at that height in the mesosphere. Read more: The secrets of night-shining clouds.
Bottom line: Photo of noctilucent clouds seen over Denmark on May 25, 2017.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.