canola – The Amazing Sky

September 7, 2013

The Great Arc of the Milky Way

The Milky Way sweeps in a great arch of light across the sky.

It’s been a wonderful week for shooting the Milky Way. I had a very clear night on Tuesday but ventured no further than a few hundred feet from home to the harvested canola field next door.

The Milky Way was beautifully placed, as it always is at this time of year, right across the sky from northeast to southwest, with the starclouds of Cygnus passing directly overhead.

The top photo is a panorama of 8 shots, with a camera on a tripod, and each exposure being just 60 seconds with a 14mm lens in portrait orientation. I stitched the segments with PTGui software, rendering the scene with its spherical projection mode which wraps the dome of the sky onto a flat surface in a way that retains the zenith detail as your eye saw it, but greatly distorts the extremities of the scene at either end.

My house is at lower right.

For this image, I used the same lens to take a single view from horizon to well past the zenith. Here the camera was tracking the stars for a set of stacked 5-minute exposures to grab even more detail in the Milky Way.

What stands out as much as the Milky Way are the green fingers of airglow stretching across the sky. These were invisible to the eye but the camera sure picks them up.

Airglow is caused by oxygen atoms, in this case, fluorescing at night as they release some of the energy they absorbed by day. It’s not aurora and generally covers more of the sky, sometimes with a diffuse glow or, as here, with more structured bands that slowly shift over minutes. It varies from night to night and can occur at any latitudes. But usually only cameras pick it up. To the eye, airglow just makes the sky look inexplicably a little less dark than you think it should be on such a clear night.

July 29, 2013

Moonshadows and Sunbeams

The play of light and shadow in the open air create wonderful effects by night and day.

The Moon and Sun have each created some wonderful sky scenes of late, aided by clouds casting shadows and sunbeams across the sky.

Above, the rising waning Moon on Saturday night shone its warm light across the prairies. Clouds cast dark shadows diverging away from the Moon.

By day, clouds created the opposite effect. Holes in the clouds let through beams of sunlight, creating rays descending from the sky dancing across the land.

Both effects are technically known as crepuscular rays. You can read much more about the phenomenon at the wonderful Atmospheric Optics website. Clouds aren’t always the evil presence in the sky astronomers take them for. They can produce stunning effects. Just look up!

July 28, 2013

Canola Field Stars

Stars in a blue sky wheel above a ripening field of yellow canola.

It’s been a couple of fine nights of nightscape shooting under the light of the waning Moon and clear skies.

I’ve been shooting from no more exotic location than my local rural neighbourhood, travelling for 5 minutes to spots near one of the many canola fields growing nearby. I wanted to grab some nightscapes over the fields before they lose their yellow flowers and turn green.

The feature image above looking north is from a time-lapse sequence and stacks several images with the “comet trail” effect, to show the northern stars turning about the North Star.

This image, also a frame from another time lapse with a longer lens, shows the Big Dipper above that same field but in an exposure short enough to prevent the stars from trailing. You can now make out the familiar Dipper pattern.

This is a very Canadian scene, with the Big Dipper high in a northern latitude sky, and with the foreground crop a Canadian one – Canola was developed in the 1970s at the University of Manitoba. The “can” in canola stands for Canada. Pity there was no aurora.

July 9, 2013July 10, 2013

Sunrise on the Plains

The Sun rises into a pastel palette of sky and earth tones.

I woke up early, just at sunrise, looked outside and wow!

I grabbed the camera and telephoto and got another nice shot right from my back deck. The canola field next to my yard is proving to be a photogenic foreground now that it’s in full bloom, just in the last couple of weeks.

There was enough haze and humidity in the air to dull the Sun to a fiery orange. The range of shades in earth and sky was wonderful. It was a classic prairie scene worth getting up for.

Being able to see the horizon is why I live on the plains and not in the foothills or mountains. And certainly not in the city!

July 7, 2013

The Milky Way over a Canola Field

The Milky Way arches over a field of yellow canola on a dark summer night.

The night was beautifully clear and moonless with a glow to the north of perpetual twilight still lingering. The Milky Way was obvious so I hiked to the middle of the canola field next to my house, visible here lit by the red lights at left.

To shoot this panorama I used the same technique as in the The Colour of Dark panorama image from last month which has proved quite popular: I shot eight exposures at 45° spacings using the 8mm fish eye lens. Each was a 60 second exposure at ISO 4000 and f/3.5. I assembled the panorama using PTGui software, from images processed in Adobe Camera Raw.

The sky was well exposed but the ground was still dark, lit only by starlight. It took some processing in Camera Raw (Shadow Detail) and Photoshop (Shadows and Highlights) to bring out the yellow field of canola in the foreground.

While the sky looked neutral grey to the eye, I’ve punched up the colours a lot to reveal the blue twilight, green and magenta aurora to the north, bands of greenish airglow across the sky, and yellow glows of light pollution.

The odd streaks of light on the canola are reflections of the horizon lights in the soaking wet dew on the canola. It was a very damp night after a day of rain.

July 5, 2013July 7, 2013

Low Bow over Canola

A horizon-hugging rainbow shines over a blooming field of canola.

You don’t often see a rainbow like this. Just the top of the bow pokes above the horizon and a field of yellow canola.

The reason is the Sun’s altitude. When I shot this in late afternoon yesterday, July 4, the Sun was 40 degrees up in the northwest. That means the point opposite the Sun was 40 degrees below the horizon in the southeast. Rainbows are centred on this anti-solar point and are always 42 degrees in radius. So doing the math shows that only the top 2 degrees of the rainbow arc could be visible above the horizon, creating a rainbow chord.

Later in the evening as another storm receded, a more classic bow appeared, this time as a double rainbow. With the Sun now much lower the anti-solar point was higher and more of the semi-circular bow appeared in the sky. I wish I could have shot a time-lapse of “rainbow rise” but downpours of rain prevented me from leaving the camera out.

These are neat examples of the play of light and colour in the open air. For lots more information, check out the wonderful Atmospheric Optics website.