The formation of noctilucent clouds is still not well understood but they are thought to consist of particles of ice condensed onto meteoric dust. Once thought of as a reasonably rare phenomenon these clouds have been making quite regular appearances of late and 2007 was a bumper year for them!

I have seen noctilucent clouds a handfull of times; spending most of your life in the south of the UK makes observations of noctilucent clouds less likely, and having a good northern horizon helps. In fact my very first sighting, which remains the most spectacular I have seen to date, was in the summer of 1996 from Alberta Canada and I'm affraid I don't have any physical record of this! The display was very bright but low to the horizon with intense white, blue, gold and red colours - a sight I won't forget. I had to wait 10 years to see any more, having moved north to Durham!