Harvest Aurora


Harvest Moon Aurora

With the harvest in full swing, the aurora and Moon lit the fields on a clear September evening.

This night, September 19, showed prospects for a good display of Northern Lights, and sure enough as it got dark a bright, well-defined arc of Lights danced to the north.

I headed off to some photogenic spots near home, on the prairies of southern Alberta. By the time I got in place, the aurora had already faded.

However, the arc still photographed well and provided a great backdrop to these rural scenes. The rising Moon, then 3 days past full, lit the foreground. In the lead image, lights from combines and trucks working the field behind the bins are at left.

Aurora and Harvest Moon at the Old Barn
A diffuse arc of aurora and the rising waning gibbous Moon light the sky over the old barn near home at harvest time, September 19, 2016. The glows from Strathmore and Calgary light the clouds to the west at far left. The Big Dipper shines over the barn, with Capella and the stars of Perseus at right. The Pleiades are rising to the left of the Moon. This is a panorama of 5 segments, with the 20mm lens and Nikon D750. Stitched with ACR.

The image above was from later in the night, just down the road at a favourite and photogenic grand old barn.

Big Dipper and Aurora over Old Barn #1
The Big Dipper and a diffuse aurora over the old barn near home, in southern Alberta, on September 16, 2016. The waning gibbous Moon off camera at right provides the illumination. This is a stack of 4 exposures, averaged, for the ground to smooth noise and one exposure for the sky to keep the stars untrailed. All 13 seconds at f/2.8 with the Sigma 20mm lens, and ISO 1600 with the Nikon D750. Diffraction spikes on stars added with Noel Carboni’s Astronomy Tools actions.

Note the Big Dipper above the barn. A waning and rising Moon like this is great for providing warm illumination.

The time around equinox is usually good for auroras, as the interplanetary and terrestrial magnetic fields line up better to let in the electrons from the Sun. So perhaps we’ll see more Lights, with the Moon now gradually departing the evening sky.

— Alan, September 20, 2016 / © 2016 Alan Dyer / www.amazingsky.com

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Arch of the Sky Above and Land Below


Harvest Moon Rising over the Red Deer River

On Friday night the Harvest Moon rose amid the arching shadow of the Earth.

This was the view on Friday, September 16 at moonrise on the Red Deer River. The view is from the Orkney Viewpoint overlooking the Badlands and sweeping curve of the river.

Above is the wide arch of the dark shadow of the Earth rising into the deepening twilight. Almost dead centre in the shadow is the Full Moon, the annual Harvest Moon.

Hours earlier the Moon passed through the shadow of our planet out at the Moon’s distance from Earth, creating a minor penumbral eclipse. No part of that eclipse, such as it was anyway, was visible from here.

But the alignment did place the Moon in the middle of our planet’s shadow projected into our atmosphere, as it does at every sunset and sunrise.

But it takes a very clear sky for the shadow to stand out as well as this in the darkening sky. I like how the curve of the shadow mirrors the curve of the river.

This is a marvellous spot for photography. I shared the site with one other photographer, at far right, who also came to capture the rising of the Harvest Moon.

The image is a 7-segment panorama with a 20mm lens, stitched with Adobe Camera Raw.

— Alan, September 17, 2016 / © 2016 Alan Dyer / AmazingSky.com

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Sweep of the Auroral Oval


Arc of the Northern Lights

The aurora has been lighting up our skies a lot in recent nights, in a great sweeping arc across the northern sky.

It’s been a good week or so for Northern Lights, with several nights in a row of fine displays. These images are from one night, taken near home in southern Alberta, on September 2.

The lead image at top shows the display at its best, with the arc of curtains reflected in a nearby pond. The green curtains fade to shades of magenta as they tower into the high atmosphere, as one process of glowing oxygen giving off green light transitions to another emitting red light.

Concentric Arcs of the Auroral Oval
A 180° panorama of the Northern Lights exhibiting classic concentric ars across the north, with an isolated arc to the east at far right. This is a stitch of 10 segments, each 2-second exposures with the 20mm Sigma Art lens at f/1.6 and Nikon D750 at ISO 3200. Stitched with PTGui.
A little later the curtains had changed form, into a more homogenous arc above a set of sharper curtains below that are farthest north. People in northern Alberta or the Northwest Territories would have been seeing these curtains dancing above them.

What we are seeing is the classic curving arc of the auroral oval, the ring of light created by electrons raining down into our atmosphere in roughly an oval sweeping across the continent and centred on the magnetic pole in the Canadian Arctic.

However, at right, you can see a odd detached bit of more southerly aurora, with a dominant red colour.

Isolated Auroral Arc #2 (Sept 2, 2016)
An isolated auroral arc to the east on September 2, 2016, shot from near home during a fine display with active curtains to the north at left. A single 8-second exposure with the 20mm lens at f/1.4 and Nikon D750 at ISO 3200.
This is a closeup, showing the characteristic form of these odd “isolated arcs” — usually featureless, often thin, without much motion, and often red.

Isolated Auroral Arc #4 (Sept 2, 2016)
An isolated auroral arc to the west on September 2, 2016, shot from home during a fine display with active curtains to the north. A single 13-second exposure with the 20mm lens at f/1.4 and Nikon D750 at ISO 3200.
Later, the arc had brightened and expanded to cross the sky. The above view is looking west from home, with the arc now displaying a mix of pink, white and green.

Isolated Auroral Arc #3 (Sept 2, 2016)
An isolated overhead auroral arc on September 2, 2016, shot from home during a fine display with active curtains to the north. The Summer Triangle stars stand out here due to high cloud fuzzing their images. A single 13-second exposure with the 20mm lens at f/1.4 and Nikon D750 at ISO 3200.
Here, we are looking up the isolated arc, with the impression of it being a thin sheet seen at an angle, with the bottom green component being closest and the red top being highest and farthest away.

Isolated Auroral Arc #5 (Sept 2, 2016)
An isolated auroral arc to the southeast on September 2, 2016, shot from home during a fine display with active curtains to the north. This one displays the classic picket fence apperarance, with fingers of green aurora that moved along the band during a time-lapse of the scene. A single 13-second exposure with the 20mm lens at f/1.4 and Nikon D750 at ISO 3200.
This is the view looking southeast to the strange aurora. For a time it broke up and displayed a “picket fence” formation. And it moved!

 

Just what these isolated arcs are is a mystery. They have been called “proton arcs,” under the assumption they are caused by incoming protons, not electrons. But while there are such things as proton arcs and auroras, they are diffuse and invisible to the eye and camera in normal visible light. So these features are not proton arcs. 

Nevertheless, these odd arcs are not like the usual auroral curtains, and likely have a different origin. But just what is still the object of research. Images by amateur astronomers such as these can help in the study.

— Alan, September 7, 2016 / © 2016 Alan Dyer / www.amazingsky.com

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A Night at Moraine Lake


Aurora over Desolation Valley PanoramaWhat a night this was – perfect skies over an iconic location in the Rockies. And an aurora to top it off!

On August 31 I took advantage of a rare clear night in the forecast and headed to Banff and Moraine Lake for a night of shooting. The goal was to shoot a time-lapse and stills of the Milky Way over the lake.

The handy planning app, The Photographer’s Ephemeris, showed me (as below) that the Milky Way and galactic centre (the large circles) would be ideally placed over the end of the lake as astronomical twilight ended at 10:30 p.m. I began the shoot at 10 p.m. as the sky still had some twilight blue in it.

Moraine Lake TPE

I planned to shoot 600 frames for a time-lapse. From those I would extract select frames to create a still image. The result is below.

Milky Way over Moraine Lake
This is looking southwest with the images taken about 11:15 pm on August 31, 2016.The ground is illuminated by a mix of starlight, lights from the Moraine Lake Lodge, and from a display of aurora brightening behind the camera to the north. The starclouds of Scutum and Sagittarius are just above the peaks of the Valley of Ten Peaks. This is a stack of 16 images for the ground, mean combined to smooth noise, and one exposure for the sky, untracked, all 15 seconds at f/2 with the Sigma 20mm Art lens and Nikon D750 at ISO 6400. The frames are part of a 450-frame time-lapse.

As the caption explains, the still is a composite of one exposure for the sky and 16 in succession for the ground, averaged together in a technique to smooth noise. The camera wasn’t tracking the sky, so stacking sky images isn’t feasible, as much as I might like to have the lower noise there, too. (There are programs that attempt to align and stack the moving sky but I’ve never found they work well.)

About midnight, the Valley of Ten Peaks around the lake began to light up. An aurora was getting active in the opposite direction, to the north. With 450 frames shot, I stopped the Milky Way time-lapse and turned the camera the other way. (I was lazy and hadn’t hefted a second camera and tripod up the steep hill to the viewpoint.)

The lead-image panorama is the first result, showing the sweeping arc of Northern Lights over Desolation Valley.

Aurora over Desolation Valley #2
The Northern Lights in a fine Level 4 to 5 display over Desolation Valley at Moraine Lake, Banff National Park, on the night of August 31/Sept 1. This is one frame from a 450-frame time-lapse with the aurora at its best. This is a 2-second exposure at f/2 with the Sigma 20mm Art lens and Nikon D750 at ISO 5000.

Still images shot, I began a time-lapse of the Lights, grabbing another 450 frames, this time using just 2-second exposures at f/1.6 for a rapid cadence time-lapse to help freeze the motion of the curtains.

The final movies and stills are in a music video here:

 

I ended the night with a parting shot of the Pleiades and the winter stars rising behind the Tower of Babel formation. I last photographed that scene with those same stars in the 1980s using 6×7 film.

Aurora and Winter Stars Rising over Tower of Babel
The early winter stars rising behind the Tower of Babel formation at Moraine Lake, Banff National Park, with a bright aurora to the north at left. Visible are the Pleiades at centre, and Capella and the stars of Auriga at left. Just above the mountain are the Hyades and Taurus rising. At top are the stars of Perseus. Aries is just above the peak of Babel. The aurora in part lights the landscape green. This is a stack of 16 images for the ground, mean combined to smooth noise, and 1 image for the sky, untracked, all for 15 seconds at f/2.2 with the Sigma 20mm Art lens, and Nikon D750 at ISO 3200. All with LENR turned on.

In a summer of clouds and storms, this was a night to make up for it.

— Alan, September 4, 2016 / © 2016 Alan Dyer / www.amazingsky.com

Member of The World at Night photo group

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