Toward the Centre of the Galaxy


Toward the Centre of the Galaxy

From southern latitudes the most amazing region of the sky shines overhead late on austral autumn nights. 

There is no more spectacular part of the Milky Way than the regions around its galactic centre. Or at least in the direction of the galaxy’s core.

We can’t see the actual centre of the Galaxy, at least not with the cameras and telescopes at the disposal of amateur photographers such as myself.

It takes large observatory telescopes equipped with infrared cameras to see the stars orbiting the actual centre of the Milky Way. Doing so over many years reveals stars whipping around an invisible object with an estimated 4 million solar masses packed into the volume no larger than the solar system. It’s a black hole.

By comparison, looking in that direction with our eyes and everyday cameras, we see a mass of stars in glowing clouds intersected by lanes of dark interstellar dust.

The top image shows a wide view of the Milky Way toward the galactic centre, taking in most of Sagittarius and Scorpius and their incredible array of nebulas, star clusters and rivers of dark dust, all located in the dense spiral arms between us and the galactic core.

Starclouds and Stardust – Mosaic of the Galactic Centre
This is a mosaic of 6 segments, each segment being a stack of 4 x 3-minute exposures at f/2.8 with the 135mm Canon L-Series

Zooming into that scene reveals a panoramic close-up of the Milky Way around the galactic centre, from the Eagle Nebula in Serpens, at left, to the Cat’s Paw Nebula in Scorpius, at right.

This is the richest hunting ground for stargazers looking for deep-sky wonders. It’s all here, with field after field of telescopic and binocular sights in an area of sky just a few binocular fields wide.

The actual galactic core area is just right of the centre of the frame, above the bright Sagittarius StarCloud.

Centre of the Galaxy Area
This is a stack of 5 x 5 minute exposures with the Borg 77mm f/4 astrograph and filter-modified Canon 5D MkII at ISO 1600, taken from Tibuc Cottage near Coonabarabran, NSW, Australia.

Zooming in again shows just that region of sky in an even closer view. The contrast between the bright star fields at left and the dark intervening dust at right is striking even in binoculars – perhaps especially in binoculars.

The visual impression is of looking into dark canyons of space plunging off bright plateaus of stars.

In fact, it is just the opposite. The dark areas are created by dust much closer to us, hiding more distant stars. It is where the stars are most abundant, in the dust-free starclouds, that we see farthest into the galaxy.

In the image above the galactic centre is at right, just above the small diffuse red nebula. In that direction, some 28,000 light years away, lurks the Milky Way’s monster black hole.

Milky Way Overhead Through Trees
This is a stack of 5 x 6-minute tracked exposures with the 15mm fish-eye lens at f/4 and Canon 5D MKII at ISO 1600. The trees appear to be swirling around the South Celestial Pole at lower right above the Cottage.

To conclude my tour of the galactic centre, I back out all the way to see the entire sky and the Milky Way stretching from horizon to horizon, with the galactic centre nearly overhead in this view from 3 a.m. earlier this week.

Only from a latitude of about 30° South can you get this impressive view, what I consider one of the top “bucket-list” sights the sky has to offer.

– Alan, April 17, 2016 / © 2016 Alan Dyer / www.amazingsky.com

 

Red Rivals in Scorpius


Red Rivals in Scorpius

Mars outshines his rival red star Antares in the heart of the Scorpion.

This was the view last night from my observing site in Australia, of red Mars shining near the red star Antares, whose very name means “rival of Mars.” But as Mars nears its closest approach to Earth next month it is already far brighter than Antares, easily winning the rivalry now.

The view takes in the head of Scorpius, one of the most colourful areas of the night sky when photographed in long exposures. Uniquely, Antares illuminates a nearby dust cloud with its light which is more yellow than red.

Other dust clouds reflect the blue light of hot young stars in this section of the Milky Way. Red nebulas are emitting their own light from glowing hydrogen.

The area around Antares is also streaked with lanes of dark dust that absorb light and at best appear a dull brown.

Mars reaches its closest point to Earth since 2005 on May 30. All through May and June Mars will shine as a brilliant red star near Antares. A telescope will provide the best view of the red planet we’ve had in a decade.

Saturn and Mars in Scorpius
This is a stack of 4 x 3 minute exposures with the 135mm telephoto lens at f/2.8 and filter-modified Canon 5D MkII at ISO 1600, shot April 14, 2016 from Tibuc Cottage, Australia.

While you are in the area aim your telescope a little to the east to catch Saturn, also in the area, though technically over the border in the constellation of Ophiuchus the Serpent Bearer.

In the view above, Saturn is the bright “star” to the left of Mars. Saturn reaches its closest to Earth in early June. Its rings are now wide open and a spectacular picture postcard sight in any telescope.

Scorpius Rising in Moonlight
This is a stack of 2 x 30-second exposures for the sky and ground, both tracked, plus a 30-second exposure through the Kenko Softon A filter to add the star glows to make the constellation pattern stand out. All with the 35mm lens at f/2 and Canon 6D at ISO 1600. Taken from Tibuc Cottage, Australia.

This final view shows Mars and Saturn rising with Scorpius in the moonlight from two nights ago. From my current latitude of 32° south, Scorpius comes up on his side.

— Alan, April 15, 2016 / © 2016 Alan Dyer  / www.amazingsky.com

Scenes from a Southern Star Party


Panorama of a Southern Hemisphere Star Party

Last week, northerners marvelled at the splendours of the southern hemisphere sky from a dark site in Australia.

I’ve attended the OzSky Sky Safari several times and have always come away with memories of fantastic views of deep-sky wonders visible only from the southern hemisphere.

This year was no exception, as skies stayed mostly clear for the seven nights of the annual star party near Coonabarabran, New South Wales.

About 35 people from the U.S., Canada and the U.K. attended, to take in views through large telescopes supplied by the Australian branch of the Texas-based Three Rivers Foundation. The telescopes come with the best accessory of all: knowledgeable Aussies who know the southern sky and are delighted to present its splendours to us visiting sky tourists.

Here are a few of the night scenes from last week.

The lead image above shows a 360° panorama of the observing field and sky from early in the evening, as Orion sets in the west to the right, while Scorpius rises in the east to the left. The Large Magellanic Cloud is at centre, while the Southern Cross shines to the upper left in the Milky Way.

Southern Sky Panorama #2 (Spherical)
This is a stitch of 8 panels, each with the 14mm Rokinon lens at f/2.8 and mounted vertical in portrait orientation. Each exposure was 2.5 minutes at ISO 3200 with the Canon 5D MkII, with the camera tracking the sky on the iOptron Sky Tracker. Stitched with PTGui software with spherical projection.

This panorama, presented here looking south in a fish-eye scene, is from later in the night as the galactic core rises in the east. Bright Jupiter and the faint glow of the Gegenschein are visible at top to the north.

Each night observers used the big telescopes to gaze at familiar sights seen better than ever under Australian skies, and new objects never seen before.

Dark Emu Rising over OzSky Star Party
This is a stack of 4 x 5 minute exposures with the Rokinon 14mm lens at f/2.8 and Canon 5D MkII at ISO 1600, all tracked on the iOptron Sky Tracker, plus one 5-minute exposure untracked of the ground to prevent it from blurring. The trees are blurred at the boundary of the two images, tracked and untracked.

The Dark Emu of aboriginal sky lore rises above some of the 3RF telescopes.

Observer Looking at Orion from Australia
This is a single untracked 13-second exposure with the 35mm lens at f/2 and Canon 6D at ISO 6400.

Carole Benoit from Calgary looks at the Orion Nebula as an upside-down Orion sets into the west.

Observer Looking at Southern Milky Way
This is a single untracked 10-second exposure with the 35mm lens at f/2 and Canon 6D at ISO 6400.

John Bambury hunts down an open cluster in the rich southern Milky Way near Carina and Crux.

Observer Looking at the Southern Sky #2
 This is a single 13-second untracked exposure with the 35mm lens at f/2 and Canon 6D at ISO 6400.

David Batagol peers at a faint galaxy below the Large Magellanic Cloud, a satellite galaxy to our Milky Way.

Check here for details on the OzSky Star Safari.

— Alan, April 11, 2016 / © 2016 Alan Dyer / www.amazingsky.com

Under the Southern Cross


Southern Milky Way Over OzSky Star Party

The Southern Cross, the iconic constellation of the southern sky, shines high in the south on austral autumn nights.

I’m in one of my favourite places, Australia, in particular at its self-proclaimed “astronomy capital,” Coonabarabran in New South Wales. Down the road from me is the Siding Spring Observatory.

But for 3 weeks I’m using my own telescope gear to observe and photograph the fabulous southern skies.

For part of my time here I’m attending the annual OzSky Star Party, a small and rather exclusive event for observers from around the world who come here to revel in celestial wonders visible only from southern latitudes.

The lead image at top is a 7-panel panorama of the star party in action, on the grounds of the Warrumbungles Mountain Motel, with a dozen or more large and premium telescopes set up for our use.

Overhead is the arch of the southern Milky Way, with the Southern Cross here at its highest about local midnight now in early April at the start of autumn. Below the Milky Way is the Large Magellanic Cloud, a companion galaxy to the Milky Way, itself a superb target for telescopes.

To the far right in the Milky Way is Sirius amid the gum trees, and the stars of Canis Major diving into the west. To the far left are the bright star clouds of Scorpius and Sagittarius rising in the east, bringing the glowing core of our Galaxy high into the austral sky. Bright Mars and Saturn shine in and around Scorpius.

This is a view of the Milky Way everyone should see – it is should be one of the top items on any amateur astronomer’s bucket list.

Star Trails over the OzSky Star Party
Circumpolar star trails over the OzSky star party near Coonabarabran, NSW, Australia, on April 3, 2016. This is a stack of 49 frames, each 45 seconds at f/2.8 with the 15mm fish-eye lens on the Canon 6D at ISO 4000. The ground comes from three frames in the sequence. Stacked with Advanced Stacker Plus actions using Streaks mode.

Here, above, I’ve stacked images from a time-lapse to create a star trail scene with the stars of the southern sky rotating about the blank South Celestial Pole. Again, the Southern Cross is at top.

Southern Milky Way from Alpha Cen to False Cross
The deep south Milky Way from Alpha and Beta Centauri (at left) to the False Cross in Vela and Carina (at right). This is a stack of 5 x 4 minute exposures at f/2.8 with the 35mm Canon L-series lens and filter-modified Canon 5D MkII at ISO 1000, with an additional similar exposure layered in taken through the Kenko Softon A filter to provide the star glows. Tracked on the iOptron Sky Tracker. 

This view, above, focuses on the Milky Way of the deep south, from Vela to Centaurus, passing through Carina and Crux, with the bright Carina Nebula, the Southern Cross, and the dark Coal Sack front and centre.

Mosaic of Crux, the Southern Cross
A 3-panel mosaic of the Southern Cross, Crux, shot April 5, 2016 from Tibuc Cottage, Coonabarabran, NSW, Australia. This is a moasic of 3 panels, each a stack of 4 x 4-minute exposures with the Borg 77mm f/4 astrograph and filter-modified Canon 5D MkII at ISO 1600. Stacked and stitched in Photoshop.

Here I zoom into the Southern Cross itself, in a mosaic of 3 panels to cover the smallest constellation using a high-resolution astrograph, a 300mm f/4 lens. The Coal Sack is at lower left while numerous star clusters lie embedded within and around the Cross, including the famous “Jewel Box” at left, next to Beta Cruxis, aka Becrux.

The Southern Milky Way and Magellanic Clouds
The deep southern Milky Way arching across the sky, from Puppis and Vela at upper right, to Centaurus at lower left. The two Magellanic Clouds are at lower centre, with the Large Cloud at top. This is a stack of 5 x 1.5-minute exposures, all tracked on the iOptron Sky Tracker, at f/2.8 with the 15mm fish-eye lens, and Canon 5D MkII at ISO 3200. The ground comes from just one of the tracked exposures to minimize blurring. Taken from the Tibuc Gardens Cottage near Coonabarabran, NSW, Australia on March 30, 2016.

I shot the Crux mosaic from my cottage site at Tibuc Gardens, a superb dark sky site and home to a new cottage built after the devastating bush fires of 2013 which destroyed all the other cottages I had stayed at in previous years.

There’s much more to come, as I rapidly fill up my hard drive with time-lapses and deep-sky images of the southern sky. I already have several blogs worth of images processed or about to be. In the meantime, check my Flickr site for the latest images hot off the hard drive and uploaded as best my Oz internet connectivity allows.

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

 

Splendid Southern Star Clusters


NGC 2477 and NGC 2451 in Puppis (77mm 5DII)

The southern Milky Way is populated by the sky’s best clusters of stars.

Here are three of the southern sky’s best star clusters, in portraits I took earlier this month from Australia.

At top, my main image takes in a great contrasting pair of star clusters. Both lie in the constellation of Puppis, once part of the ship Argo Navis.

At left is the stunningly rich NGC 2477, so packed with stars it almost ranks as a globular cluster, not one of the sparser open clusters. At least that’s the impression it gives in the eyepiece. But instead of containing hundreds of thousands of stars, as do globulars, NGC 2477 “only” has 300 stellar members. They are just very tightly packed in one of the richest open star clusters in the sky. If it had been farther north NGC 2477 would certainly rate as one of the top 100 sky sights, and carry some memorable name after a fanciful resemblance to who knows what! Instead, it carries but a catalog number.

Next to it, at right, is NGC 2451, more typical of open clusters. It has a central bright star, this one naked eye, surrounded by 40 or so lesser stars of contrasting colour and brightness. The two clusters make a great side-by-side comparison in any low-power telescope.

NGC 6067 in Norma Star Cloud (77mm 5DII)

Much farther along the southern Milky Way is this rich open cluster (above), NGC 6067, in Norma, itself embedded in one of the richest star clouds of the southern Milky Way, the Norma Star Cloud. Here you are gazing for 6800 light years toward the cluster which shines suspended against the background of the even more distant inner arms of our spiral galaxy.

So NGC 6067 looks a little like an island of blue stars amid the dust-reddened background of more distant stars in the Milky Way — an island in a sea of stars.

– Alan, April 29, 2014 / © 2014 Alan Dyer

 

 

Stellar Graveyard in Vela


Vela Supernova Remnant (77mm 5DII)

This is what’s left of a star that exploded in ancient times.

This is the Vela Supernova Remnant, an object in the southern sky in the constellation of Vela the Sail. The wispy tendrils of magenta and cyan are all that’s left of the outer layers of giant star that exploded about 12,000 years ago.

Cluttering the field at left are amorphous patches of star-forming nebulosity that are part of the much larger Gum Nebula complex.

The supernova was only about 800 light years away so it would have been a brilliant sight in the sky to neolithic observers, far outshining any other stars. But no record exists of anyone seeing it.

The star didn’t destroy itself completely – its core collapsed to form a pulsar, an ultra-dense ball of neutrons, in this case spinning about 11 times a second. The pulsar is in this field but it’s much too faint to show up in visible light.

I shot this earlier this month from Australia where Vela sails directly overhead. The field is about 6° by 4°, the amount of sky framed by high power binoculars. The brighter parts of the Vela Remnant can be picked out in large amateur telescopes – I’ve seen bits of it in my 10-inch telescope – but this is certainly a challenging object to see, even with aided eyes.

— Alan, April 23, 2014 / © 2014 Alan Dyer

 

 

Star Scenes in Scorpius


Scorpius Overhead (50mm 5DII)

Scorpius, one of the most photogenic of constellations, contains a wealth of amazing sky sights.

My trip to the land down under is coming to an end but I’m still working through the dozens of deep-sky images I was able to take under the southern stars. The wide-field scene above takes in all of Scorpius, shot with the constellation sitting directly overhead in the pre-dawn hours of an austral autumn. You can trace the scorpion’s winding shape down from his head and claws at top, to his curving stinger tail at bottom.

M6 and M7 Star Clusters in Scorpius (77mm 5DII)

Off the stinger of the scorpion shine two naked-eye star clusters, Messier 6 and 7 (the close-up photo above). M6 is the Butterfly Cluster, seen here sitting in a dark region of the Milky Way at upper right. Its companion, M7, a.k.a. Ptolemy’s Cluster at left of the frame, is lost amid the bright star fields  that mark the direction of the galactic core.

NGC 6334 Cat's Paw Nebula (77mm 5DII)

In the curving tail of the scorpion lie two patches of nebulosity. At upper left is NGC 6357, but the triple-lobed NGC 6334 at bottom right is also known as the Cat’s Paw Nebula.

False Comet NGC 6231 Area (77mm 5DII)

Further up the tail of the scorpion sits this fabulous region of space that is a stunning sight in binoculars. NGC 6231 is the blue star cluster at bottom, which garnered the name The False Comet Cluster back in early 1986 when many people mistook its fuzzy naked eye glow for Comet Halley then passing through the area. The camera reveals the region filled with glowing hydrogen gas.

Antares & Rho Ophiuchi Area (77mm 5DII)

But the standout region of Scorpius lies at its heart. Here, the yellow-orange star Antares lights up a dusty nebula surrounding it, reflecting its yellow glow. At top, another dusty nebula surrounds the star Rho Ophiuchi, reflecting its blue light. Glowing hydrogen gas adds its characteristic magenta tints. This is one of the most colourful regions of the Milky Way.

I shot these images with 50mm normal and 300mm telephoto lenses two weeks ago during the OzSky Star Safari near Coonabarabran, NSW, Australia. For all I used a filter-modified (by Hutech) Canon 5D Mark II camera.

— Alan, April 17, 2014 / © 2014 Alan Dyer