Dawn Sky Delights


Aldebaran About to be Occulted by the Moon

It was one of those mornings when the sky was full of wonder.

After days and nights of smoke from unfortunate fires burning not far away, including in my favourite national park of Waterton Lakes, the sky cleared enough this morning, September 12, to reveal some fine sights.

At 6 a.m. the waning gibbous Moon passed in front of the star Aldebaran in Taurus. It is performing many such occultations of Aldebaran this year, but most aren’t well seen from any one location. This one was ideal, right from my backyard.

The lead image is a “high dynamic range” stack of several exposures showing the waning Moon and star set in some high haze adding the sky colours.

The star winked out behind the Moon’s bright limb as the Moon advanced from right to left (west to east) against the background sky.

Occultation of Aldebaran
Aldebaran nearing the limb of the Moon.
This shows a composite sequence, with images of the star taken every four minutes blended with a single image of the Moon. While it looks like the star is moving, it is really the Moon that is edging closer to Aldebaran.

The star reappeared from behind the dark limb of the Moon, but five minutes after sunrise, with the Moon in a bright blue sky. Still, the star stood out nicely in binoculars and in the telescope for this view.

Aldebaran Near the Moon in Day Sky
Aldebaran off the dark limb of the Moon.
Aldebaran is the point of light at right, just off the invisible edge of the Moon.

I shot stills and video, and compiled them into this short video.

Enlarge it to full screen to view it properly.

Meanwhile, over to the east the twilight sky was awash in planets.

Rocky Planets at Dawn with Labels (Sept. 12, 2017)
The line of dawn planets, with labels.
All the three inner terrestrial worlds were there: Venus, at top, Mercury below Regulus, and Mars lowest of the trio. Of course, a fourth terrestrial world is in the photo, too – Earth!

Mercury was at its greatest western elongation this morning, placing it as far from the Sun and as high in the sky as it gets, with this autumn appearance the best of 2017 for a morning showing for Mercury. Even so, you can see how Mercury is always low and easy to miss. However, this morning it was obvious to the naked eye.

Mars and Mercury will be in close conjunction at dawn on the morning of September 16.

Rocky Planets at Dawn (Sept. 12, 2017)

It was a fine morning to be up early and enjoy the solar system show.

— Alan, September 12, 2017 / © 2017 Alan Dyer / amazingsky.com

 

The Night-Shadowed Prairie


The Night Shadowed Prairie

“No ocean of water in the world can vie with its gorgeous sunsets; no solitude can equal the loneliness of a night-shadowed prairie.” – William Butler, 1873

In the 1870s, just before the coming of the railway and European settlement, English adventurer William Butler trekked the Canadian prairies, knowing what he called “The Great Lone Land” was soon to disappear as a remote and unsettled territory.

The quote from his book is on a plaque at the site where I took the lead image, Sunset Point at Writing-on-Stone Provincial Park.

The night was near perfect, with the Milky Way standing out down to the southern horizon and the Sweetgrass Hills of Montana. Below, the Milk River winds through the sandstone rock formations sacred to the Blackfoot First Nations.

The next night (last night, July 26, as I write this) I was at another unique site in southern Alberta, Red Rock Coulee Natural Area. The sky presented one of Butler’s unmatched prairie sunsets.

Big Sky Sunset at Red Rock Coulee

This is “big sky” country, and this week is putting on a great show with a succession of clear and mild nights under a heat wave.

Waxing Crescent Moon at Red Rock Coulee

The waxing crescent Moon adds to the western sky and the sunsets. But it sets early enough to leave the sky dark for the Milky Way to shine to the south.

The Milky Way at Red Rock Coulee

This was the Milky Way on Wednesday night, July 27, over Red Rock Coulee. Sagittarius and the centre of the Galaxy lie above the horizon. At right, Saturn shines amid the dark lanes of the Dark Horse in the Milky Way.

I’m just halfway through my week-long photo tour of several favourite sites in this Great Lone Land. Next, is Cypress Hills and the Reesor Ranch.

— Alan, July 27, 2017 / © 2017 Alan Dyer / amazingsky.com

 

The Austral Moon of Evening


Waxing Moon in Evening Twilight Colours

From the southern hemisphere the Moon appears “upside-down” and higher each night in the northern sky as it waxes from crescent to Full.

These are scenes from the last week as the Moon rose higher into the evening sky as seen from Australia.

A northerner familiar with the sky would look at these and think these are images of the waning Moon at dawn in the eastern sky.

Waxing Crescent Moon at Cape Conran
The “upside-down” waxing crescent Moon in the evening sky from Victoria, Australia, at Cape Conran, West Cape area, on the Gippsland Coast, at latitude 37° South. Earthshine lights the dark side of the Moon. This was March 31, 2017. The Moon lights a glitter path on the water. This is a single 1.3-second exposure at f/2 with the 85mm Rokinon lens, and Canon 5D MkII at ISO 400.

But no, these are of the waxing Moon (the phases from New to Full) with the Moon in the evening sky.

From the southern hemisphere the ecliptic – the path of the planets – and the path of the Moon arcs across the northern sky. So as the Moon waxes from New to Full phase it appears to the right of the Sun, which still sets in the west. The world still spins the same way down under!

So the Moon appears upside down and with the crescent phase the “wrong” way for us northerners.

Panorama of the Waxing Moon at Sunset at Welshpool Harbour
A 240° panorama from 16 segments.

This panorama taken April 4 sweeps from northwest to southeast, but looks north at centre, to capture the scene at sunset of the waxing 8-day gibbous Moon in the northern sky as seen from the southern hemisphere.

The angle between the Sun and Moon is just over 90°, shown here by the angle between the right-angle arms of the wharf, pointed to the west at left, to the north at centre, and to the east at right.

The Sun has set just north of west, while the Moon sits 13° east of due north. The Earth’s shadow rises as the blue arc at far right to the east opposite the Sun.

Philip Island Sunset and Waxing Moon Panorama
A 240° panorama from 15 segments.

The next night, April 5, I shot this panorama from Philip Island south of Melbourne. Again, it shows the waxing gibbous Moon in the north far to the right of the setting Sun in the west (at left).

Getting used to the motion of the Sun and Moon across the northern sky, and the Moon appearing on the other side of the Sun than we are used to, is one of the challenges of getting to know the southern sky.

Things just don’t appear where nor move as you expect them to. But that’s one of the great delights of southern star gazing.

— Alan, April 8, 2017 / © 2017 Alan Dyer / www.amazingsky.com

 

End of Year Skies


New Moon for a New Year

The crescent Moon rises into the western evening sky as 2016 ends, while Venus shines bright, and Orion rises into the east.

Getting clear skies is a rare treat of late, but these are images from two such nights this week. On December 30, the thin waxing Moon appeared in the colourful twilight of a winter night. Despite the clouds and the Moon’s low altitude, the dark side of the Moon is plainly visible illuminated by Earthshine.

Venus in Twilight over Pioneer Grain Elevators

Venus is now brilliant as an evening star in the southwest. Here is it over the old wood grain elevators at Mossleigh, Alberta, some of the few of these landmarks left standing on the prairies.

Fainter Mars shines above Venus and over the month of January, Venus will climb up to meet Mars by month’s end for a fine conjunction with the crescent Moon as well. Watch through January as Venus and Mars converge.

Orion and Pioneer Grain Elevators

As the planets set into the southwest, Orion the Hunter rises into the east. Here it is over the Mossleigh elevators, illuminated by local lights.

Enjoy the winter skies as clouds permit!

Clear skies and Happy New Year!

— Alan, December 31, 2016 / © 2016 Alan Dyer / www.amazingsky.com

 

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

TWAN-black

 

The Cadence of the Moving Sky


Saturn, Mars and the Milky Way over the Bow River

Saturn, Mars and the Milky Way appeared in the twilight over the Bow River.

I shot this scene on August 24 from the viewpoint at Blackfoot Crossing Historical Park, overlooking the Bow River. Mars appears between Saturn above and Antares below, in a line of objects west of the Milky Way.

The valley below is the traditional meeting place of the Blackfoot Nation, and the site of the signing of Treaty Seven between Chief Crowfoot and Colonel MacLeod of the North West Mounted Police in 1877.

The image is a panorama of two images, each 20-second exposures at f/2 and ISO 1600 with the 24mm lens. I shot them just prior to shooting time-lapses of the moving sky, using two cameras to create a comparison pair of videos, to illustrate the choices in setting the cadence when shooting time-lapses.

The movies, embedded here, will be in the next edition of my Nightscapes and Time-Lapse ebook, with the current version linked to below. The text explains what the videos are showing.

 

Choose Your Style

When shooting frames destined for a time-lapse movie we have a choice:

  • Shoot fewer but longer exposures at slower ISOs and/or smaller apertures.

OR …

  • Shoot lots of short exposures at high ISOs and/or wide apertures.

 

The former yields greater depth of field; the latter produces more noise. But with time-lapses, the variations also affect the mood of a movie in playback.

This comparison shows a pair of movies, both rendered at 30 frames per second:

Clip #1 was taken over 2 hours using 20-second exposures, all at ISO 2000 and f/2 with 1-second intervals. The result was 300 frames.

Clip #2 was taken over 1 hour using 5-second exposures also at f/2 and 1-second intervals, but at ISO 8000. The result was 600 frames: twice as many frames in half the time.

Clip #1 shows fast sky motion. Clip #2 shows slow motion.

Clip #2 exhibits enough noise that I couldn’t bring out the dark foreground as well as in Clip #1. Clip 2 exhibits a slower, more graceful motion. And it better “time-resolves” fast-moving content such as cars and aircraft.

Which is better? It depends …

Long = Fast

The movie taken at a longer, slower cadence (using longer exposures) and requiring 2 hours to capture 300 frames resulted in fast, dramatic sky motion when played back. Two hours of sky motion are being compressed into 10 seconds of playback at 30 frames per second. You might like that if you want a dramatic, high-energy feel.

Short = Slow

By comparison, the movie that packed 600 frames into just an hour of shooting (by using short exposures taken at fast apertures or fast ISOs) produced a movie where the sky moves very slowly during its 10 seconds of playback, also at 30 frames per second. You might like that if you want a slow, peaceful mood to your movies.

So, if you want your movie to have a slow, quiet feel, shoot lots of short exposures. But, if you want your movie to have a fast, high-energy feel, shoot long exposures.

As an aside – all purchasers of the current edition of my ebook will get the updated version free of charge via the iBooks Store once it is published later this year. 

— Alan, August 26, 2016 / © 2016 Alan Dyer / AmazingSky.com

 

Moon and Star Conjunction


Moon and Aldebaran (July 29, 2016)

The waning Moon shone near the bright star Aldebaran in the dawn sky.

This was a beautiful sight this morning, before dawn on July 29. The crescent Moon, its night side illuminated by Earthshine, shone just below the brightest star in Taurus.

We are currently in 3-year period when the Moon’s path is taking it near or in front of Aldebaran every month. However, most of these occultations or conjunctions are not well-timed for any particular location. And many involve the too-brilliant gibbous or full Moon.

But this morning the timing and Moon phase were perfect. From my longitude on Earth in Alberta, the Moon passed closest to the star just before the sky was getting too bright with dawn. Having them set against the deep blue twilight was perfect.

From farther east the Moon would not have appeared as close to Aldebaran as this before sunrise. From farther west the Moon and star would have appeared much lower in the sky at closest approach.

Moon & Aldebaran Screen

TECHNICAL:

For this image I shot 6 exposures, from 2 seconds for the Earthshine, twilight sky colour and stars, to 1/125th second for the bright crescent. I then stacked, aligned, and blended them together using luminosity masks – masks that hide or reveal parts of the image based on the brightness of the scene. You can see them in the Photoshop screen shot – Click on the image to enlarge it.

How do you create these masks?

• Turn off all the layers except the one you want to create a mask for.

• Go to Channels and Command/Control Click on the RGB Channel.

• That automatically selects all the highlights.

• Go back to the image layer and then hit the Add Mask button down at the bottom of the Layers panel (the rectangle with the black dot in it).

• Done. Repeat that for each image layer.

More traditional high dynamic range or “HDR” stacking left odd colour fringing artifacts and double images on the slowly moving Moon, despite applying what is called “de-ghosting” and despite using a mount tracking at the lunar rate. I tried merging the images with HDR, but it didn’t work.

A nifty Photoshop action from the Astronomy Tools set by Noel Carboni added the diffraction spikes.

I shot all images with the 130mm Astro-Physics refractor at f/6 and the Canon 60Da camera at ISO 400.

— Alan, July 29, 2016 / © 2016 Alan Dyer / www.amazingsky.com