Night of the Noctilucent Clouds


Star Trails and Noctilucent Clouds (Lighten Stack)

It was a beautiful summer evening, with stars wheeling overhead in a moonlit sky and the only clouds far away and interesting.

This was one of those nights we get once or twice a summer when the much-anticipated noctilucent clouds – the clouds of summer – put on a perfect show. In my previous post I featured an image from early in the night, last night, June 26, 2013.

These are images and time-lapse movies from later in the night. The composite image above shows stars trailing over 90 minutes with the brilliant noctilucent clouds on the horizon, and fringed by a rosy glow of red twilight where the southern edge of the cloud display, which sits over the Northwest Territories, is being lit by a setting Sun with red sunlight filtering through our atmosphere as it passes over the North Pole.

Noctilucent Clouds and Thunderstorm (June 26, 2013)

This telephoto lens shot above captures a close-up of the rosy-fringed noctilucent clouds, behind a lightning-lit thunderstorm rolling through storm alley in central Alberta. The storms can stay there! We’ve had enough of them for a while!

 

My time-lapse sequence extends over about 90 minutes and opens with a wide-angle view of the display as it appeared low on the horizon. What follows are two closeup views that really show the intricate wave-like motion of these high-altitude mesospheric clouds, and their changing lighting and colours.

These are beautiful clouds drifting on the edge of space but it takes time-lapse to reveal their fluid-like motion.

– Alan, June 27, 2013 / © 2013 Alan Dyer

 

Thunderstorm and Noctilucent Clouds


Noctilucent Clouds and Thunderstorm (June 26, 2013)

Two very different forms of clouds drift along the horizon: a thunderstorm nearby and low, and noctilucent clouds far away and high.

This was the scene last night, as another thunderstorm to the north of me rolled along the horizon drifting away to the east. A bolt of lightning illuminates the storm clouds. The thunderstorm was over central Alberta, and at the bottom of our atmosphere, in the troposphere.

Meanwhile, in the background, a beautiful display of noctilucent clouds crept along the horizon in the other direction, drifting to the west. These clouds were over the Northwest Territories, a thousand or more kilometres away to the north and 80 to 100 kilometres high, at the top of the atmosphere in the mesosphere.

The NLC display lasted all night, or for at least as long as I was able to stay up and shoot.

This is a telephoto lens shot that zooms into the brightest part of the NLC display.

– Alan, June 27, 2013 / © 2013 Alan Dyer

 

Time-Lapse: Northern Lights and Noctilucent Clouds


Northern Lights and Noctilucent Clouds (135mm #1) (June 9, 2013)

What strange clouds these are, moving where there shouldn’t be winds, and forming where there’s barely any air.

These are noctilucent clouds, sometimes called polar mesospheric clouds. Their icy strands form around particles at the top of the atmosphere some 80 km up. There’s almost no air up there so just how these clouds form has always been a mystery. They may be condensing around meteoric dust particles. They may also be more common now than in past decades and centuries, as the upper atmosphere cools due to an odd quirk of global warming that sees the lower troposphere warm while the upper mesosphere cools.

This was the first display of NLCs I’ve seen so far this season. They can only be seen, and indeed they only form, in summer. Sunlight streams over the pole and lights these clouds all night long. They are literally “night-shining” clouds. Only from a latitude range of 45° to 60° north and around summer solstice is the geometry right to see the clouds, usually as electric blue cirrus strands moving slowly along the northern horizon.

The time-lapse movies capture their motion over 30 to 90 minutes of shooting.

 

The 40-second movie contains three clips:

• The first, a wide-angle  view of the amazing aurora that danced in fast accompaniment to the slow noctilucent clouds.

• The second clip, very short, zooms in a little more to the northern horizon. However, I cut that sequence short so I could switch lenses and take the next clip.

• The third scene is with a telephoto lens, framing the east-to-west slow motion of the clouds. I took 4-second exposures at 1-second intervals so it shows some pretty fine motion.

This was certainly one of the best NLC displays I’d seen and my best shot at capturing them.

What was especially rare was seeing them accompanied by auroral curtains actually moving among the clouds (or so it appeared). Both are up high in the near vacuum of near space, but they may have been miles apart in latitude.

– Alan, June 10, 2013 / © 2013 Alan Dyer

Northern Lights & Noctilucent Clouds


Northern Lights and Noctilucent Clouds (june 9, 2013)

Colourful sky phenomena combine to provide a remarkable sky show.

What a night this was! On Sunday, June 9 the aurora kicked off with a burst in the bright twilight but really got going as the sky got dark, shooting beams of magenta and blue up from the main green arc.

Then on cue, streamers of noctilucent clouds appeared low in the north, shining with their characteristic electric blue. These are odd clouds at the edge of space lit by sunlight streaming over the Pole.

Both these apparitions of the upper atmosphere glowed above a horizon rimmed with the orange of perpetual twilight set in a deep blue background sky.

Yes, the camera has brought out the colours more intensely than the eye saw, but nevertheless it was a remarkable evening close to solstice. This is a magical time of year when all kinds of sky glows light the night.

This night the European Einstein ATV cargo craft also flew over, twice, each time about 10 minutes ahead of the even brighter Space Station that it is chasing for a docking later this week.

More images to come from this night, including time-lapses of the Lights and Clouds.

– Alan, June 10, 2013 / © 2013 Alan Dyer

The Clouds Keep Coming!


Clouds aren’t usually the astronomer’s friend, but at this time of year they become the objects of our attention. For the past few nights, my Alberta prairie skies have been beautifully clear and filled with the clouds of solstice.

Last night, July 6, began at twilight with the best display of noctilucent clouds so far this season — and we’re now at peak season for this northern sky phenomenon. This was the scene at about 11:30 pm local time, with the wispy high-altitude clouds at their most extensive and fully lit by sunlight. Over the next hour or so, as the Sun set further below the horizon, the display disappeared as darkness came to the high atmosphere and the Sun no longer illuminated these clouds suspended over the Arctic. Here’s a diagram of the geometry of how they get lit up. If you are curious to learn more, check this NASA page.

I took a time-lapse movie of the fall of darkness on the clouds, which you can view here at my SmugMug gallery at AmazingSky.ca. The video shows how the clouds begin the night fully illuminated by the Sun but over the hour duration of the video they disappear from top to bottom. You can see a curtain of darkness moving down the clouds, caused by the Sun dropping farther below the horizon. As it does so its illumination seems to drop toward the horizon as night falls, leaving only clouds closest to the horizon (and farthest north) still illuminated. The video also shows that the edge of the illumination appears reddish — that’s because clouds on the edge of the descending dark shadow are being lit only by a low red Sun setting below the limb of the Earth. Pretty neat, and something I’ve not seen before in any image or movie. (The movie is HD quality and will take a while to load, sorry!)

However, tonight normal, everyday weather clouds moves in, curtailing any late night NLC watch. Tomorrow, I head to the Rockies to do some time-lapse nightscape shooting in the mountains. Yes, I know I’ll miss seeing Duke and Duchess Will and Kate start off the Calgary Stampede Parade. Royalty will just have to get on without me.

— Alan, July 7, 2011 / Image © 2011 Alan Dyer

Arctic Ice-Blue Clouds at Dawn


We were treated to a good display of noctilucent clouds last night. Or should I say early this morning! At this time of year, many a night is spent keeping a watchful vigil for noctilucent clouds. They often appear at their best before dawn.

That was the case July 5/6. The night started with a decent display of these northern sky clouds in the northwest after sunset and just before midnight. But then as the Sun dropped lower below the horizon, the lighting angles changed and the clouds disappeared. A low aurora display took their place through most of the night.

Then, at 3 am or so, as the lighting from the rising Sun hit the right angle coming over the Pole, the Arctic ice clouds reappeared, now in the northeast. Sequences of shots showed a rapid east to west motion of the clouds, driven by winds at the edge of space, at the clouds’ extreme altitude of 80 km or so.

This shot is with a 16-35mm zoom, set to 24mm and takes in the bright star Capella at upper right, a useful “survey marker” for measuring angles and cloud altitudes. I took this at about 3:30 am. MDT.

— Alan, July 6, 2011 / Image © 2011 Alan Dyer

The Glowing Clouds of Solstice Appear


The glowing clouds of solstice have appeared. This was my first sighting of “noctilucent clouds” for the season.

Every northern summer in late June and early July we are often treated to bright pearly clouds glowing along the northern horizon long after sunset. Their origin remains somewhat of a mystery. These clouds form almost at the edge of space, so high there shouldn’t be much for clouds to form around. But their height is what makes them visible, as they catch sunlight streaming over the pole even in the middle of the night.

I took this shot Tuesday, June 28 just before midnight. The noctilucent clouds are the blue-white wavy bands just above the orange twilight. In front of them lie dark normal clouds low in our troposphere. But the NLCs shine from an altitude of some 80 km, well into the mesosphere. They are located over the Northwest Territories but, like aurora, their height allows us to see them even from more southerly latitudes.

The bright star Capella, circumpolar from my latitude of 51° North, shines through the clouds at right.

— Alan, June 28, 2011 / Image © 2011 Alan Dyer