Saturday, June 24, 2017

'Tis The Season For Noctilucent Clouds....

Yesterday morning when I was reviewing my overnight time lapses I saw that my cameras had captured a brief glimpse of some noctilucent clouds.  We got home late last night and once again, you could see some unusual lighting on the horizon.  This was a very faint event, but the conditions are just right for a real show.  I thought I’d drop a few factoids here about Noctilucent clouds as a reminder that this IS the season to keep an eye to the Northern sky after sunset or before sunrise.
Every year around the summer solstice we have “slight” chance to see this beautiful event.  Noctilucent clouds are ice crystals VERY high in the atmosphere.  Specifically, between 47 and 53 miles up. 

For reference, here are the atmospheric levels:
Exosphere: 440 to 6,200 miles
Thermosphere: 50 to 440 miles
Mesosphere: 31 to 50 miles
Stratosphere: 7 to 31 miles
Troposphere: 0 to 7 miles

These clouds are straddling the Mesosphere and Thermosphere…. 

They can only be seen during deep twilight.  In our area this would be 45 to 90 minutes before sunrise or after sunset.   They appear as white, streaky clouds.  

Here is an image from last summer.

These clouds are very rare for us because they are only visible be 50 and 70 degrees latitude.  We are roughly 47 to 48 degrees here.

Another interesting fact is there were no documented reports of Noctilucent clouds prior to 1885.  The videos below really need to be viewed full screen.

Here is a time lapse of the event from last summer:

Here is the “hint” of some noctilucent clouds in the last 48 hours.

Keep your eyes to the north if you are up early or stay up late.....

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