Noctilucent Clouds 2021-06-05

Noctilucent (“night-shining”) clouds are the highest in the atmosphere, at around 76-85km altitude. They only appear in the summer months at latitudes from 50-70º (north or south), when the sun is more than 6º below the horizon. Formed in the mesosphere at very cold temperatures from ice, dust and water vapour, their gossamer threads undulate and shimmer in shades of electric blue.

There was a particularly decent display on Friday/Saturday morning – I nipped out and spent a happy hour making the video:

Timelapse: Sony a7r3, Sigma 14-24mm lens, SkyWatcher StarAdventurer tracking mount for rotation

Stills: Fuji X-T4, 16-80 f/4 lens

A selection of the images are available as prints, masks, cards and other products (even socks and jigsaw puzzles!) from my main website: ShinyPhoto: Noctilucent Clouds

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…

…followed by a noctilucent cloud display around 1am:

NLCs are the highest-flying clouds, occurring at altitudes up to 80km where the next highest type (cumulonimbus) only reaches 12km and most are lower still. Most typically they resemble a fine silver filigree of ice-cold pale blue, although more complex forms have been seen. First maybe-seen in 1885, they only really came to prominence since the 1980s, as a canary for changes in the upper atmosphere linked to climate change.

As I stood and watched the display, a patch of silver mist formed over Strathearn and made its way west along the A85 toward Crieff, so I made a little timelapse video – 17 minutes’ data compressed into 1:

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 here at the moment. Still. While that precludes shooting the aurora, instead it’s noctilucent cloud (NLC) season – just started in the past couple of days so I was very pleased to capture these last night / this morning around 1am.

Apart from being a canary for global warming, NLCs are a beautiful phenomenon, glowing cold bluey-white typically filament threads lighting up the sky. Or, if you leave the camera thinking for 2 minutes they blur nicely with the more mundane clouds:

Noctilucent Clouds, around 1am – Crieff across Strathearn from Auchterarder
A total 2 minutes of exposure to see what the NLCs and ordinary clouds would get up to over that kind of timescale.

And I made a short timelapse – 6 minutes compressed into an 11-second video:

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 away into the distance… and a clear display of noctilucent clouds above Kinnoull Hill.

From wikipedia:

Night clouds or noctilucent clouds are tenuous cloud-like phenomena that are the “ragged edge” of a much brighter and pervasive polar cloud layer called polar mesospheric clouds in the upper atmosphere, visible in a deep twilight. They are made of crystals of water ice. Noctilucent roughly means night shining in Latin. They are most commonly observed in the summer months at latitudes between 50° and 70° north and south of the equator. They can be observed only when the Sun is below the horizon.

They are the highest clouds in Earth’s atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometres (47 to 53 mi). They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are in the Earth’s shadow. Noctilucent clouds are not fully understood and are a recently discovered meteorological phenomenon; there is no record of their observation before 1885.