The Noctilucent Clouds are Back!

[Aratus]

I spent decades trying to see these 80 mile high clouds of illuminated meteorite dust, and saw my first only 2 years ago. They are summer thing visible after the sun has gone down for an hour or so. Imagine were the sun is under the horizon, and the noctilucent clouds will be a few degrees above the horizon. I find that if you can see the star 'Capella', you are looking in the right sort of place. The photo below isn't the best example, but it gives some idea of what they look like. At their best the whole northern sky is full of glowing ripples. Observation over time show them twisting and knotting in the rarified atmosphere. Very occasionally a meteor diving into the surface will produce circular patterns indstinguishable from those produced by a stone thrown into water . . .

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[The Happy Parrot]

Nice image Aratus. Reminds of a post from the Jet Propulsion lab three days ago about clouds on Mars including noctilucent ones. NASA JPL (@NASAJPL) Tweeted:

Science under the clouds

After working hard for 2,405 Martian days and discovering the highest amounts of clays yet during the mission, @MarsCuriosity took a quick selfie break:

[Aratus]

I didn't know about the Martian noctilucent clouds.

The strange thing is that no astronomy book I read in the 1970s considered the phenomena common enough to mention. Today it features quite highly in the list of things to see in the sky. It is a welcome addition to the sky at a time when other observations are hard to find. I hope we get a lot of reports of new sightings this year.

[seer]

I just checked and my book PRACTICAL ASTRONOMY by Storm Dunlop has a write up about them. It says they are normally observable between latitudes 45 and 60 degrees approximately. My latitude is 40.328. Do I come within that approximation?