July 2011 – The Amazing Sky

July 31, 2011

The Eagle and the Swan

Though they are truly “nebulous,” these clouds of interstellar gas carry fanciful names — our human attempt to make sense of the vast chaotic forms that pervade deep space.

Above is the Eagle Nebula, a.k.a. Messier 16. Below lies the Swan Nebula, a.k.a. Messier 17. Through a telescope to the eye these nebulas do take on the imagined shape of interstellar birds flying along the Milky Way. But long exposure images like this bring out far more than the eye can see. The entire field, here about the width of what high-power binoculars take in, is filled with swirls of hydrogen gas, glowing in its characteristic red colour.

The Eagle Nebula lies in the constellation of Serpens the serpent, while the Swan Nebula lies just over the border in Sagittarius the archer.

I took this shot Saturday night, July 30, 2011, on one the few perfect nights of observing we get here in Canada — the night was warm, dry, with little wind and no mosquitoes. I could venture out with just a sweater on for a bit of warmth. A far cry from the parkas and down-filled boots normally needed.

This field is a first for me from Canada. I’ve shot it from Australia and Chile, where these objects lie overhead, never from home in Alberta at a latitude of 51° North. But the night was so transparent, the field was worth going after, despite it being low on the southern horizon and at its best for no more than an hour after it got dark.

To shoot the field, I used the wonderful little Borg 77mm f/4 astrographic refractor, effectively a 300mm telephoto lens but far sharper and flatter than most telephotos made for sports and wildlife. The camera was the Canon 5D MkII, a filter-modified version that has a special filter for passing more of the deep red colour of hydrogen. But the real difference here was the use of a filter at the focus of the telescope that further isolated the red wavelengths and blocked other colours that might have otherwise fogged the image, especially from a field so low on the horizon. It worked great, though does tend to render the whole field on the red side.

July 30, 2011August 11, 2011

Sacred Site: The Movie

Here’s my time-lapse sequence of the hoodoos at Writing-on-Stone Park lighting up as the Moon rises and the Milky Way sets.

The sky starts off dark but lights up as the waning Moon, off frame behind the camera, rises and lights up the foreground and sky. The sequence ends as the sky brightens with the onset of dawn.

Waning moons are great nights for this type of shooting as the changing lighting produces dramatic effects as the landscape lights up at moonrise. The problem is, the Moon doesn’t rise till very late, making for a long night of shooting.

I assembled this sequence from 290 frames, each a 60-second exposure, taken at 1-second intervals over about 4 hours. The camera was the Canon 7D and the lens the 10-22mm Canon EF-S zoom at 10mm. I also shot a matching sequence simultaneously with the 8mm fish-eye and Canon 5D MkII camera, for an all-sky sequence for planetarium use.

July 30, 2011July 30, 2011

Sacred Site

Standing among these “hoodoo” rock formations at night with moonlight and starlight for illumination was a magical moment. This is a scene at Writing-on-Stone Provincial Park in southern Alberta, that I took last Saturday night, July 23, 2001 at 3 a.m.

It shows the summer Milky Way arching over the sandstone formations, with the rocks lit by the light of the rising waning Moon in the east.

Writing-on-Stone is a sacred site for First Nations people, a place to connect to the spirit world through dreamquests. No one lived here — it was a place haunted by the spirits — people only visited at special times. The rocks were also used to record visions and historic events, in the form of carved petroglyphs that are among the best preserved and most extensive of any archaeological sites in North America. By day or by night, Writing-on-Stone is an inspiring location, carved in the rocks on the banks of the Milk River (see the previous blogs for some panoramic sunset views of the area).

This is one frame of about 300 taken as part of a time-lapse movie, and is a 60-second exposure with the Canon 7D and 10-22mm lens.

July 27, 2011August 11, 2011

Sunset on the Sweetgrass Hills

My previous blog featured a still frame from a time-lapse movie I took of sunset on the Sweetgrass Hills and Writing-on-Stone Provincial Park. Here’s the full movie, taken at sunset on July 22, 2011.

I assembled the movie in Photoshop Extended CS5 from 678 frames taken over nearly an hour, at 5-second intervals, beginning before sunset and continuing until well after sunset. The camera was the Canon 7D and lens the 10-22mm lens at 10mm.

Putting the camera into automatic Aperture-priority mode keeps the exposure uniform as the lighting level drops but does induce some slight flickering from minor shot-to-shot variations in exposure. That can be fixed in “post!” But it’ll be a while before I get around to that!

July 27, 2011

The Great Lone Land

This is one of the great places for evoking the wide open spaces of the high plains. Here we are looking south over the Milk River and the rock formations of Writing-on-Stone Provincial Park in Alberta to the peaks of the Sweetgrass Hills in Montana. The buildings at right are the modern reconstructions of the late 1800’s North West Mounted Police outpost that guarded Canada from the illegals from the U.S. (!) coming up Police Coulee smuggling whiskey from Montana into Canada.

The time is just after sunset, as the last light of the Sun still illuminates the clouds. This is the magic hour for photography, and for taking in the solitude of the “Great Lone Land” as author William Francis Butler described it in his book of that title in 1872.

As Butler wrote, “No ocean of water in the world can vie with its gorgeous sunsets; no solitude can equal the loneliness of a night-shadowed prairie…”

July 25, 2011

Dawn Sky Serenity

Some sky scenes are worth getting up early for. This was the dawn sky this morning, July 25, at about 4:20 a.m., looking east to the rising crescent Moon, which this morning appeared near the Pleiades star cluster. You can see it just above the overexposed Moon.

The waning Moon also sits between two planets now in the pre-dawn sky: Jupiter, the bright object at upper right, and Mars, about the same distance away from the Moon but to the lower left. Mars, the Moon and Jupiter form a diagonal line across the dawn sky that defines the dawn ecliptic. Also in the scene is the V-shaped Hyades star cluster, and the bright star Aldebaran, just below the Moon.

This was a 5-second exposure with the Canon 24mm lens at f/3.5 and Canon 5D MkII camera at ISO 800.

July 22, 2011

Stars Over Waterton Lakes II

When I’m doing time-lapse sequences I often run two cameras, one with a wide-angle lens for a frame-filling rectangular view for “normal” HD movies (that’s what’s in the previous blog post), and another camera with a fish-eye lens for a circular format “all-sky” view. These scenes are for projection in full-dome digital planetariums.

This still image is one frame of 470 that I took over four hours on the night of July 20/21, showing the stars and clouds moving in the sky over Waterton Lakes National Park and the stately Prince of Wales Hotel on the bluff across the bay. North is at the bottom of the frame in this shot.

I took this image about 11:30 pm when the sky still had some twilight glow in it and just before the waning Moon was about to rise at right. So the eastern sky has a glow from the impending moonrise. However, the sky is dark enough that the Milky Way shows up running across the sky and down toward the hotel.

You can also see the Big Dipper at left and Cassiopeia at right. The Summer Triangle stars are at top right, in the south. Polaris, the North Star, is dead centre.

July 22, 2011

Stars over Waterton Lakes

One of my favourite places is Waterton Lakes National Park. Even now, in 2011, the little town seems like Banff was back in the 1960s, before huge developments, resort hotels and endless shopping malls. Even at peak season the town is quiet and laid back.

It’s been a while since I had visited Waterton but was determined to this summer. A couple of days here yielded one clear night and a couple of 4-hour time-lapse sequences of stars turning over Waterton’s landmark, the Prince of Wales Hotel.

The hotel is a wood chalet-like structure built in 1927 by the Great Northern Railway as one in a chain of grand railway hotels. It sits on a bluff overlooking Waterton Lakes and remains the elegant place to stay or dine while in Waterton.

For this shot I set up at the end of the marina dock, looking north toward Polaris, the Big Dipper and Cassiopeia. This is a single 30-second exposure taken in deep twilight at the beginning of the night with the 10-22mm lens and Canon 7D camera. It’s one of 400+ frames taken for a time-lapse sequence. While lights from the hotel interior are somewhat picturesque and inviting it’s a pity that national parks still employ unshielded sodium vapour lights on roads. The streetlights are so bright and glaring they actually illuminate the mountainsides.

July 19, 2011July 19, 2011

Circling the Sky II

My encounter with the old farmstead near home continued the next night (after the shot featured in the previous blog), under another stunningly clear moonlit sky. Here I let the camera fire away for three and half hours, producing a rather neat juxtaposition of surreal starfield above an abandoned old farmhouse.

For this shot I stacked 660 17-second exposures that were taken in rapid succession at one second intervals. I used the Canon 5D MkII at ISO 800 and Sigma 8mm lens at f/4.5.

My workflow for an image like this is to…:

1. Use Adobe’s Photo Downloader to download all the images from the camera card into a folder on a local hard drive, then open Adobe Bridge to inspect them. Toss out any junk shots at the beginning and end of the set.

2. Open a representative image in the sequence using Adobe Camera Raw and process it for Colour Correction, Contrast, Noise Reduction, Vibrance, Fill Light (to bring out shadow detail) and Recovery (to recover details in highlights).

3. Then in Bridge, go under Edit: Develop Settings: Copy Camera Raw Settings.

4. Select all the images (Select All) and then Paste Camera Raw Settings. This applies that custom setting to all the images in the sequence in one fell swoop. 600+ images processed in seconds! Sometimes it can take a few iterations to get a good setting that works well through the whole set.

5. Then Select All again in Bridge and go under Tools: Photoshop: Image Processor. This open Photoshop itself and brings up a dialog box that allows you to convert those processed RAW files into other formats (JPGs, TIFFs, etc. in whatever size you want). For this type of single image I convert the RAWs into full resolution TIFFs. While I am at it, I’ll also convert each image into a smaller-sized (1080 pixels high) JPG. The folder of JPGs are for creating an HD-format time-lapse movie from the same set of images. Image Processor can create two sets of images simultaneously from the same RAW master. Very nice.

6. This will take a while as Image Processor dutifully opens up each image one by one and creates a TIFF (and a JPG, too, if you like) from each RAW file in another folder. Go for a very leisurely coffee!

7. Once a folder of finished TIFFs is there, I can use Chris Schur’s Photoshop Action to take each of those images and stack them one by one into a single image. That process can take hours with full-res TIFFs. Start it before you go to bed! Slow, yes, but it’s better than doing it all by hand.

8. The final image can still use touch-ups, to sharpen, alter the brightness and contrast of the sky (frames taken when the sky was still bright with twilight can make the scene look too bright).

It can take a day’s worth of computer crunching to get a final image. But the result is certainly unique.

July 18, 2011July 19, 2011

Circling the Sky

It has been an incredible week for imaging. Clear skies and a bright Moon are the tickets to nightscape photography. And in the last week we’ve had clear moonlit nights in abundance.

I’ve taken advantage of the run of great weather to shoot an old farmstead down the road from my house, on several nights. This is a shot from the first night out, on Thursday, July 14. It is a fish-eye lens shot taking in most of the sky, and looking north at the bottom of the frame. The star trails, taken over 2 hours, circle around the North Star (or close to it).

So why is the sky blue? The Full Moon, just out of the frame at top, is illuminating the landscape and sky — and light from the Full Moon is the same colour as light from the Sun (because that’s what moonlight is! — reflected sunlight). It’s just that moonlight is much dimmer. Expose long enough and you get a scene that looks like daylight but has the stars in it.

To create this image I took 400 18-second exposures, taken 1 second apart, using the Canon 5D MkII camera at ISO 800 and the Sigma 8mm lens at f/5. I stacked the images using an automated “action” for Photoshop developed by astrophotographer Chris Schur. The original frames can also be strung together in sequence to create a time-lapse movie of the sky turning, suitable, in this case, for projection in a full-dome digital planetarium. I’ll post some of those shortly.

But after several nights of shooting till 3 and 4 a.m., and accumulating 100 gigabytes or more of RAW files, it’s time to take a night off and turn in early! At 1 a.m.!

July 11, 2011July 12, 2011

Moon Over Banff Springs Hotel

A weekend in Banff National Park — but three cloudy nights foiled the array of starry time-lapse shots I had hoped to take. But on Sunday night, July 10, I did get a nice evening shot of the Moon over the most famous Banff landmark.

This is the Banff Springs Hotel, in the deepening twilight as the gibbous Moon shone over Sulphur Mountain behind the hotel. I shot this from the overlook across the Bow River on Tunnel Mountain Drive, a popular spot by day for tourists to disembark by the busload and get their requisite shot. But at this time of night, about 11 p.m., I was the only one there. That’s the beauty of nightscape photography — you have the scene to yourself! And the bears.

Banff Springs is the epitome of a grand hotel. Opened in 1888 but since reconstructed and added to several times, the hotel was built by the Canadian Pacific Railway as the focal point for the tourists it planned to bring into the new Rocky Mountain Park, to take “the waters” in the Park’s sulphur hot springs and enjoy mountain wilderness in genteel splendour. I had the pleasure of staying there one night, in an upper room, courtesy of the Hotel as part of an astronomy outreach program we did there for Earth Hour in 2010. It was truly splendid!

For this shot, I combined three different exposures (1/2 second, 1.3 seconds and 3.4 seconds) in a High Dynamic Range stack, to bring out dark foreground detail but retain the still bright sky, and prevent the Moon from becoming too overexposed. So some Photoshop trickery was involved. But unlike many picture postcard scenes of the Moon sitting above a landmark, this one is real and has not had the Moon pasted into place, usually in a spot and orientation that is astronomically impossible! We astronomers hate that!

July 7, 2011July 7, 2011

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.

July 6, 2011July 6, 2011

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.