galactic centre – The Amazing Sky

May 1, 2017

The Amazing Austral Sky

Panorama of the Milky Way Overhead

The latitude of 30° South is the magic latitude on Earth for seeing the Milky Way.

From that region of the world – southern Australia, central South America, southern Africa – the centre of the Galaxy passes overhead, and you see the view at top.

You see the galactic core glowing brightly at the zenith, and the arms of the Milky Way stretching off to the horizon on either side of the core – to Aquila at left, for the northern half of the Galaxy, and to Carina at right, for the southern half of the Galaxy. That area of the Galaxy is always below the horizon for viewers at northern latitudes.

The image below focuses in on just the southern portion of the Milky Way, framing what in Australia is called the “Dark Emu,” a constellation made of the dark lanes along the Milky Way, from his head at right in Crux, to his tail at left in Scutum.

The Dark Emu Overhead

This is the most amazing region of the Milky Way, and is worth the trip south of the equator just to see, by lying back and looking up. You can easily see we live in a vast Galaxy, and not in the centre, but off to one side looking back at the core glowing overhead.

I would say there are three sky sights that top the list for spectacle:

• A bright all-sky aurora

• A total solar eclipse

• and the naked eye view of the Galaxy with its centre overhead and its arms across the sky from horizon to horizon.

I’ve checked off two this year! One more to go in August!

May 17, 2015May 17, 2015

Scenes at the Texas Star Party

The stars at night shine big and bright, deep in the heart of Texas.

Last week several hundred stargazers gathered under the dark skies of West Texas to revel in the wonders of the night sky. I was able to attend the annual Texas Star Party, a legendary event and a mecca for amateur astronomers held at the Prude Ranch near Fort Davis, Texas.

Some nights were plagued by clouds and thunderstorms. but here are some scenes from a clear night, with several hundred avid observers under the stars and Milky Way. Many stargazers used giant Dobsonian reflector telescopes to explore the faintest of deep-sky objects in and beyond the Milky Way.

A 360° panorama of the upper field of the Texas Star Party at the Prde Ranch near Fort Davis, TX, May 13, 2015, taken once the sky got astronomically dark. The panorama shows the field of telescopes and observers enjoying a night of deep-sky viewing and imaging. Venus is the bright object at right of centre and Jupiter is above it. The Zodiacal Light stretches up from the horizon and continues left across the sky in the Zodiacal Band to brighten in the east (left of centre) as the Gegeneschein. I shot this with a 14mm lens, oriented vertically, with each segment 60 seconds at f/2.8 and with the Canon 5D MkII at ISO 3200. The panorama is made of 8 segements at 45° spacings. The segments were stitched with PTGui software. — A 360° panorama of the upper field of the Texas Star Party at the Prde Ranch near Fort Davis, TX, May 13, 2015, taken once the sky got astronomically dark. The panorama shows the field of telescopes and observers enjoying a night of deep-sky viewing and imaging. Venus is the bright object at right of centre and Jupiter is above it. The Zodiacal Light stretches up from the horizon and continues left across the sky in the Zodiacal Band to brighten in the east (left of centre) as the Gegeneschein.
I shot this with a 14mm lens, oriented vertically, with each segment 60 seconds at f/2.8 and with the Canon 5D MkII at ISO 3200. The panorama is made of 8 segements at 45° spacings. The segments were stitched with PTGui software.

Observers at the Texas Star Party explore the wonders of the deep sky under the rising Milky Way, in May 2015. Sagittarius and Scorpius are in the background, with the centre of the Galaxy rising in the southeast. This is a single 30-second exposure at f/2 with the 24mm lens and Canon 5D MkII at ISO 4000.

Expert deep-sky observers Larry Mitchell and Barbara Wilson gaze skyward with Larry’s giant 36-inch Dobsonian telescope at the Texas Star Party, May 2015. This is a single 60-second exposure with the 14mm lens at f/2.8 and Canon 5D MkII at ISO 3200.

A deep-sky observer at the top of a tall ladder looking through a tall and large Dobsonian telescope, at the Texas Star Party, May 2015. Scorpius is rising in the background; Saturn is in the head of Scorpius as the bright star above centre. Anatares is just below Saturn. This is a single 30-second exposure at f/2.5 with the 24mm lens and Canon 5D MkII at ISO 6400.

Circumpolar star trails over the upper field of the Texas Star Party, May 13, 2015. The star party attracts hundreds of avid stargazers to the Prude Ranch near Fort Davis, Texas each year to enjoy the dark skies. The three observing fields are filled with telescopes from the basic to sophisticated rigs for astrophotography. I aimed the camera to look north over the field to capture the stars circling around Polaris in circumpolar trails over about 1 hour. Some cloud and haze obscured parts of the sky. Lights from cities to the north add the sky glow at right. The streaks at top are from the stars of the Big Dipper. This is a stack of 55 exposures, each 1 minute long, at f/2.8 with the 14mm lens and Canon 5D MkII at ISO 3200. The foreground comes from a single image in the series, masked and layered in Photoshop. The images were stacked using the Long Trails tapering effect with the Advanced Stacker Actions from Star Circle Academy. — Circumpolar star trails over the upper field of the Texas Star Party, May 13, 2015. I aimed the camera to look north over the field to capture the stars circling around Polaris in circumpolar trails over about 1 hour. Some cloud and haze obscured parts of the sky. Lights from cities to the north add the sky glow at right. The streaks at top are from the stars of the Big Dipper.
This is a stack of 55 exposures, each 1 minute long, at f/2.8 with the 14mm lens and Canon 5D MkII at ISO 3200. The foreground comes from a single image in the series, masked and layered in Photoshop. The images were stacked using the Long Trails tapering effect with the Advanced Stacker Actions from Star Circle Academy.

I extend my thanks to the organizers for the great event, and for the opportunity to speak to the group as one of the featured evening speakers. It was great fun!

April 11, 2014April 11, 2014

The Galactic Archway of the Southern Sky

The southern Milky Way arches across the sky, with the centre of the Galaxy overhead at dawn.

This was the sky at 4:30 this morning, as Venus rose in the east (to the right) amid the zodiacal light, and with the Milky Way soaring overhead. This image is a 360° panorama of the scene, with the zenith, the overhead point, at the top centre of the frame.

The location is the Two Styx Cabins, on the border of New England National Park in New South Wales, Australia. The cabin with the light on (I left it on on purpose for the photo) is where I stayed for two nights in splendid isolation.

The panorama is a stitch of 6 frames shot with an 8mm fish-eye lens, each 1-minute exposures on an untracked tripod. I used the PTGui software program to assemble the pan.

Below is an alternative rendering, in spherical format, to create the more classic “fish-eye” view, but one extending well below the horizon. So this is not one image but a stitch of six.

In this version you can more readily see the spectacle of the Milky Way at dawn in the southern hemisphere autumn months, with the bulge of the galactic core directly overhead as seen from this latitude of 30° south. It is a wonderful sight.

This is my last view of it for this trip. Till next year!

June 14, 2013

The Milky Way at Solstice

The centre of the Galaxy culminates over a starlit landscape on a night near the summer solstice.

This was last weekend, on the same night I took the images of the aurora and noctilucent clouds featured in the previous two blog posts. But toward the end of the shoot, I turned south to capture this scene, of the Milky Way over a grassy prairie field.

The landscape is lit only by starlight and by the glow of twilight and aurora to the north.

In the sky, the constellations of Scorpius and Sagittarius are peaking as high as they get for me in southern Alberta. The red giant star Antares is to the right while the bright star clouds toward the centre of our Galaxy are just left of centre. The sky is not dark because of the glow of perpetual twilight at this time of year near solstice.

Deep sky fans will note that the star cluster M7, the southernmost Messier object, is just clearing the horizon.

Remarkably, this is a mere 15 second exposure, at ISO 1600 but with the 24mm lens wide open at f/1.4. Normally I wouldn’t shoot at that wide an aperture as the images look too distorted at the corners of the frame. But for this shot I used the Canon 60Da camera – its cropped-frame sensor records only the central area of what the lens projects so it crops out the nasty stuff at the corners of the frame that would certainly have been detracting had I used the full-frame camera.

But shooting at f/1.4 allowed even this quickie 15-second shot to grab lots of detail in the Milky Way.

October 1, 2011June 1, 2014

Milky Way Mosaic

It’s taken me a few months to get around to the task, but at last! — my mosaic of the Milky Way I shot in Chile back in May.

The panorama is made up of 6 frames, stitched and blended together, extending from Crux, the Southern Cross (at right) to Aquila the eagle (at left) — a sweep of the Milky Way from Acrux to Altair! The mosaic is centred on the core of the Galaxy in Sagittarius and Scorpius.

Panoramas like this allow you to step back a distance and take in the big picture:

— You can see the large-scale structure of the dust clouds and the odd diagonal sweep of many of the clouds cutting across the plane of the Galaxy. I’ve never heard an explanation of why the dust lanes seem to have that structure and direction. I also see a 3D effect, with the nearby dust clouds hanging in front of and obscuring the bright starclouds of the distant inner spirals arms of our Galaxy.

— Also apparent are the extensive dust clouds at left extending from Ophiuchus (at top) down into Aquila, well below the plane of the Galaxy. Most wide-angle shots of the Milky Way I see tend to process out the subtle brown clouds that extend far off the Galactic plane. And they are brown, not black.

— And what really stands out is the band of bright blue stars from Scorpius (at top centre) to the right above the Milky Way through Lupus, Centaurus then down into Crux. This is a section of Gould’s Belt, a ring of hot blue stars around the sky that runs at an angle of about 20° to the Milky Way. This ring of hot, nearby stars surrounds us in our spiral arm and is thought to be only about 65 million years old, likely caused by some disturbance in our spiral arm which set off a wave of star formation close to us.

— And … as my Australian friends will point out, you can see the entire Dark Emu, made of the dust lanes from the Coal Sack in Crux at right (his head and beak), through the curving lanes in Centaurus (his neck), then sweeping up and over the centre of the Galaxy (his body) then down into Scutum and Aquila (his two feet and his tail).

I took this panorama from the Atacama Lodge in north central Chile, using the Canon 5D MkII and Canon 35mm lens. Each of the 6 segments that went into this pan was itself a stack of 4 x 6 minute exposures, plus a fifth exposure through a soft-focus filter, all at f/4 and ISO 800. The camera was on a Kenko SkyMemo tracking platform. I assembled the pan with Photoshop CS5’s Photomerge command. This is actually only half of the full panorama mosaic, which extends for another 5 segments to the right along the Milky Way to Orion, taking in the entire southern portion of the Milky Way. But this is the best bit!