On Solstice Pond


Selfie at Solstice Pond

Solstice nights have been filled with twilights, planets, and noctilucent clouds.

Astronomers tend to curse the short nights and late sunsets of summer solstice. But the bright nights do offer unique sights.

Over the last few nights I’ve set up at what I call “Solstice Pond,” a prairie slough near home ideal for shooting the aurora to the north and, at this time of year, the glow of twilight and noctilucent clouds.

Below is the view on the night before solstice, looking north toward the glow of “perpetual twilight” that lights the northern horizon at solstice time from my latitude of 50° north.

Solstice Twilight Panorama over Prairie Pond
A 120° panorama of the summer solstice twilight (at 12:30 am local time) looking north over the prairie pond near home in southern Alberta, taken June 19/20, 2018. Some very faint noctilucent clouds are at left but fading, while some very faint rays of auroral curtains are also visible in the photo but were invisible to the eye. The bright star Capella is at centre and reflected in the calm waters. Perseus is at right of centre. The red lights at right are from the wind turbines at the Wintering Hills Wind Farm. This is a stitch of 6 segments, with the 35mm lens at f/2.5 for 20 seconds each with the Canon 6DMkII at ISO 400.

From farther north the twilight would be more prominent, while above the Arctic Circle at 66° N latitude, the twilight turns to full daylight as the Sun never sets.

The view looking south this night, with the Moon just off frame at right, includes the Milky Way at centre, with Saturn embedded, flanked by bright Jupiter at right and reddish Mars at left, both casting shimmering “glitter paths” on the still waters.

Planet Panorama at a Prairie Pond
A 160° panorama looking south near summer solstice time in June 2018, with the bright planets Mars (left) and Jupiter (right) and their glitter paths on the water flanking the Milky Way and Saturn in Sagittarius above the pinkish Lagoon Nebula. The waxing Moon is setting off frame at right brightening the sky and lighting the landscape. The sky is also blue from the solstice twilight. The stars of Scorpius shine between Jupiter and the Milky Way. Some faint bands of red and green airglow are visible at left, despite the bright sky. This is a stitch of 8 segments, all for 25 seconds with the 35mm lens at f/2.2 and Canon 6D MkII at ISO 800.

A few nights later (below), on June 24, the star of the solstice sky put in an appearance. Bright noctilucent clouds (NLCs) shone to the north, reflected in the pond.

These are water vapour clouds 80 kilometres high at the edge of the atmosphere – in the mesosphere – almost in space. They form over the Arctic in summer, and are high enough to remain sunlit even in the middle of the night as they catch the Sun shining over the pole.

Southern Western Canada – the Prairies where I live – is well-placed to see them, as we are far enough north to see them in our sky, but not so far north that our sky is too bright.

Noctilucent Clouds over Prairie Pond (June 24, 2018)
A fine display of noctilucent clouds (NLCs) or polar mesospheric clouds, reflected in a local prairie pond near home in southern Alberta. The display started with wisps much higher in the north but they faded as the Sun dropped lower, with the display at this extent by the time I reached my spot and took this panorama. Leo and Regulus are setting at far left in the west, as is Venus just above the horizon at left. Capella and Auriga are at centre, and circumpolar, while the stars of Perseus at right, rising. This is a panorama of 9 segments, at 15° spacings, with the 35mm lens at f/2.8 for 13 second exposures with the Canon 6D MkII at ISO 400. Stitched with Adobe Camera Raw.

An even better display appeared two nights later, on June 26, brighter and with more structure.

The curving arc of the top of the display defines the most southerly edge where sunlight is able to reach. That edge drops lower through the first part of the night, as the Sun itself drops lower below the horizon. This causes less of the NLC display to be sunlit.

Panorama of Noctilucent Clouds (June 26, 2018)
A panorama of a fine display of noctilucent clouds across the northern horizon over an angle of about 60°. This was on June 26, 2018 at about 11:45 pm. Capella is just left of centre. The display faded as the solar illumination dropped and the clouds darkened from the top down. This was from the small pond near home in southern Alberta. This is a stitch of 7 segments, each 2 seconds at f/2.8 with the 85mm Rokinon lens and Canon 6D MkII at ISO 400. Stitched with ACR.

You can see this effect of the changing illumination of the clouds in this time-lapse compilation from June 26 (below).

Also notice the waving motion of the clouds. It is as if the NLC material is flowing over standing waves in the atmosphere – and it is! The waves are called “gravity waves,” and are bumps in the high atmosphere created by disturbances far below in the normal layers of the atmosphere, the stratosphere and troposphere.

The video includes two clips shot simultaneously: from a camera with a 24mm wide-angle lens, and from a camera with an 85mm moderate telephoto. Expand to view full screen in HD.

The motion, here over an hour or more, is hypnotic. The NLCs move right to left (east to west), while the dark normal weather clouds on the horizon are blowing left to right (west to east). The stars are also turning left to right. The water ripples in the wind, while ducks swim by.

It was a magical night at Solstice Pond.

– Alan, June 27, 2018 / © 2018 Alan Dyer / AmazingSky.com 

 

The Clouds of Solstice Twilight Are Here!


Noctilucent Clouds Panorama #1 (June 21-22, 2014)

Look north in June and July from the Canadian Prairies and you are likely to see iridescent clouds shimmering in the mid-summer twilight. 

It’s been a good couple of nights for sighting noctilucent clouds – literally “night shining” clouds, or NLCs. These are odd water vapour clouds that form at the edge of space 80 km up where no self-respecting cloud has a right to exist.

But there they are. Existing and moving in waves in a near vacuum.

We see them because at solstice time the Sun’s light pours over the pole (where the midnight Sun is shining) and lights up the clouds that hang over the Canadian Northwest Territories and Nunavut.

Noctilucent Clouds and Big Dipper

From the Prairies we see them far in the distance to the north, as here, shining low on the horizon amid the deep blues and reds of a perpetual twilight that never ends on our short summer nights.

The top photo, taken Saturday night, is a 5-section panorama with a short telephoto lens. The bottom image, taken early this morning, is just the opposite – a very wide angle shot showing the clouds in context, with the Big and Little Dippers at top left and centre.

Some images and movies from last year’s NLC season are in my blog post from June 27, 2013.

– Alan, June 23, 2014 / © 2014 Alan Dyer

 

Fireflies Dancing on Solstice Eve


Fireflies and Stars

A field of fireflies dances under the stars on the eve of summer solstice.

On Friday, June 20, the night before summer solstice, I had a superb night at home watching storm clouds, fireflies and the glow of perpetual solstice twilight.

June is firefly season and on a warm night I see them dancing and flickering above the grassy field. They appear here as green sparkles and streaks, with the stars above and Milky Way just showing through in the blue of a solstice twilight.

Flashes from distant lightning help illuminate the ground and clouds.

Iridium Satellite Flare (June 20, 2014)

These frames are from a time-lapse sequence, with the frame above picking up few fireflies. But it did reveal the streak from an Iridium satellite flaring in the sunlight as it flew overhead.

While the sky from my latitude of 51° North never gets dark at this time of year it is filled with other beautiful sky glows and phenomena.

– Alan, June 22, 2014 / © 2014 Alan Dyer

 

Summer Solstice Panorama on the Prairie


Summer Solstice Panorama

This is the prairie night sky taken at the moment of summer solstice.

I shot this 360° panorama in the field near my house just before midnight on June 20, 2013, right about the official time of summer solstice. This is the longest night of the year and the brightest. The presence of the gibbous Moon contributes most of the night light, but there to the north at left you can see the glow of twilight and an aurora. At right, the waxing Moon shines in clouds, surrounded by a faint halo from ice crystals in the clouds.

Nights around solstice are always bright and filled with wonderful colours and atmospheric phenomena.

The tranquility of the solstice scene is in contrast with the horrific weather disaster taking place west of me near the mountains, as record floods from torrential rains wash away roads, railway lines, and houses. Roads are closed in and out of the mountains and entire neighbourhoods of Calgary near rivers are being evacuated.

Everyone knows somebody who is affected. For many this is indeed a very long and stressful night. I hope everyone keeps safe.

– Alan, June 21, 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

The Colour of Dark


Colors of the Dark Sky Panorama

What colour is the dark night sky? Depending on conditions, it can be any colour you want.

I shot this 360° panorama last night from my backyard under what looked like a clear and fairly dark, moonless sky. Looks can certainly be deceiving. The camera picked up all kinds of colours the eye couldn’t see.

Let’s review what’s causing the colours:

• To the north just left of  centre the horizon is rimmed with a bright yellow glow from all-night perpetual twilight present around summer solstice at my mid-northern latitude.

• Above that shines a green and magenta band from a low-level aurora just visible to the naked eye.

• Much of the sky is tinted with bands of green from ever-present airglow, caused by oxygen atoms at the top of the atmosphere giving off at night some of the energy they absorbed by day. I had thought the sky would look blue from the perpetual twilight but the airglow seems to overwhelm that.

• Yellow glows around the horizon at left (west) and right (southeast) are from urban light pollution from towns 50 km away.

• Some strands of remaining cloud from a departing thunderstorm add streams of brown as they reflect lights from below.

• Finally, the Milky Way shows up in shades of yellow and pale blue, punctuated here and there by red patches of glowing hydrogen hundreds of light years away.

The only thing missing this night was a display of electric blue noctilucent clouds.

The sources of most of these colours are an anathema to observers of faint deep-sky objects. Aurora, airglow and certainly light pollution just get in the way and hide the light from the distant deep sky.

A word on technique:
I shot this panorama using an 8mm fish-lens to shoot 8 segments at 45° spacings. I used the excellent software PTGui to stitch the segments together, which it did seamlessly and flawlessly. Each segment was an untracked 1 minute exposure at ISO 3200 and f/3.5. The panorama covers 360° horizontally and nearly 180° vertically, from the ground below to the zenith above. It takes in everything except the tripod and me!

– Alan, June 8, 2013 / © Alan Dyer

All-Night Satellites


ISS Pass #2 (June 4-5, 2013)

It was a marvellous night for Space Station watching.

Right now those of us at northern latitudes in North America are enjoying the opportunity to see the International Space Station come over not once but often 2 or 3 times a night, as it is now lit by the Sun all night long (on our nights down here on Earth, that is).

Here are two shots from the night of June 4-5, 2013 taken from my home in Alberta at a latitude of 51° North.

My featured image above is from the ISS pass that began at 1:55 am, and is a stack of 4 tracked 2.5-minute exposures, so the stars are not trailed, but the ground is! On this pass, the ISS came overhead. This view is looking north, toward the all-night perpetual twilight we see on the Canadian Prairies around summer solstice. There’s also a low band of green aurora on the northern horizon.

I shot the image below on the ISS’s pass one orbit earlier at 12:18 am. This image is looking south to the ISS’s high pass across the south. It’s a composite of 4 untracked 2-minute exposures –  thus the stars are now trailing in circles around Polaris at the top of the frame.

ISS Pass #1 (June 4-5, 2013)

Both shots are horizon-to-horizon all-sky views with an 8mm fish-eye lens.

The sky isn’t dark, even in the shot taken at 2 am. At this time of year around summer solstice at northern latitudes, the sky never gets astronomically dark but is lit a deep blue by sunlight still streaming over the pole and bathing the night in a glow of perpetual twilight.

– Alan, June 5, 2013 / © 2013 Alan Dyer