photo #4361807

Dana Dudakova (Cloud Appreciation Society Member 56,284) and her boyfriend spotted clouds shining bright against the night sky at around 2.30 am over Sipoo, Finland while driving back home from the airport. Dana was convinced they were noctilucent clouds, extreme-altitude formations that develop 50 miles (80 km) up in the high atmosphere. They form at the top of the mesosphere, far higher than the normal weather clouds. Up there, at the fringes of Space, they catch the light when the Sun is well below the horizon and the lower sky is dark. Dana’s boyfriend was not convinced. He claimed they were just Cirrus clouds that were catching the moonlight. But Dana would not be swayed. It was the middle of July, and noctilucent clouds form in the summer months – typically between May and August for the Northern Hemisphere (November to March in the Southern). Not only was the month right, so was their location. Night-shining clouds like these only tend to appear at latitudes higher than 50°. This region of Finland is at a latitude of 60°. Though exhausted from their travels, Dana was ‘excited as hell’ and refused to accept her boyfriend’s doubts. She likened the clouds to magical spells in the sky.We are glad to confirm that she did indeed spot a classic example of these mysterious formations, which are also known as Polar Mesospheric Clouds. One other requirement for their appearance is that the Sun needs to be at the correct angle over the horizon, typically between 6° and 16° beneath it. At this time of night in this location, it would have been 7° below. Bingo! But Dana didn't need our reassurance. ‘I just knew these had to be noctilucent clouds!’ she said. ’At last, I could tick the box and add them to my cloud collection!’