Noctilucent ("night-shining") clouds are the highest in the atmosphere, at around 76-85km altitude. They only appear in the summer months...
A Day In Clouds
That was 2017-06-20, that was. A beautiful blue sky with white fluffy wispy cirrus cloud catching the setting sun... [gallery...
Noctilucent Clouds (NLCs) 2017-06-15
It's just a week off being the longest day, and it seems never to really get dark at night around...
Noctilucent Clouds, Perth, 20150623
A classic location for long-exposure night-time photography: standing on the bridge over the M90 at Rhynd, with the road snaking...