Adrian Jannetta writes...
It's turning out to be another good season for noctilucent clouds! NLCs, for short, are the highest clouds on the atmosphere and are formed by water vapour condensing onto meteor smoke about 50 miles above the ground. They are a strictly summer phenomenon (end of May to start of August) and they only form near the poles of our planet. In Northumberland we are in a perfect position to see them each year. I've written a more detailed article about NLCs here. A history of observation and photos of NLC types can be seen here.
NASA produce an up-to-date image of NLC coverage - click here. A clear night doesn't guarantee seeing NLCs but it's always worth a look outside, about 90 minutes after sunset at this time of year. Look towards the northern horizon. You might mistake NLCs for cirrus clouds at first but the white or electric blue colour will grow brighter as the sky around them darkens.
Here are some pictures I've taken in the last week or so.
NLC season should last another 2-3 weeks but NLC appearances will soon begin to diminish as the upper atmosphere heats up again towards the end of summer.
Dr Adrian Jannetta FRAS
Amateur astronomer and mathematics teacher. Guitar strumming explorer of the universe!
Proud nerd and founder of the school space club. A young whippersnapper with a bucket-load of passion.