Milky Way Mosaic

Centre of the Milky Way Panorama (2011)

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!

— Alan, Oct 2, 2011 / Image © 2011 Alan Dyer

Centaurus, Creator of Constellations

In George Lucas mythology, Luke Skywalker went to Yoda to learn the wisdom and ways of heroes. In Greek mythology, heroes the likes of  Achilles, Jason and Hercules sought out Chiron, the wise and kindly Centaur, who taught them science, astronomy, medicine, music, arts, hunting and archery.

Centaurs, the romping half man/half horse creatures, were a riotous and drunken lot, but not immortal Chiron. He was the offspring of Kronos and the ocean nymph Philyra and served as tutors to many legendary heroes. One reference in my library suggests Chiron actually invented the constellations, to make it easier for mankind to keep track of the stars and the season. To reward his work, Zeus placed Chiron in the stars, becoming by some accounts, this southern sky constellation, Centaurus.

However, most writings suggest Chiron is actually the Zodiac constellation of Sagittarius, while the constellation we call Centaurus is one of the wilder bunch, depicted in the sky as carrying the slain Lupus the wolf, drawn here in the fainter blue stars at top centre.

The bright stars at right are the main stars of Centaurus, including Alpha and Beta Centauri at lower right. Beta Centauri is the blue star, a giant some 390 light years away. But just to the left of Beta is yellow-white Alpha Centauri, a Sun-like star (or actually a pair of them orbiting each other) just 4.3 light years away.

Alpha and Beta Centauri sit at the start of a long dark rift in the Milky Way that splits into fingers of nebulosity reaching into Norma, Ara and Scorpius, here at the left edge of the frame.

I took this shot of Centaurus and Lupus in Chile last month, using a 50mm lens and a Canon 5D MkII. It’s a stack of four 6-minute exposures at f/4 and ISO 800, layered in with two exposures shot through a Kenko Softon-A filter to produce the photogenic star glows.

— Alan, June 26, 2011 / Image © 2011 Alan Dyer






Into the Heart of the Scorpion

Here we peer into the heart of Scorpius, to a place where the sky is painted with pastel hues unlike anywhere else in the heavens.

The yellow star at bottom is Antares, the cool supergiant star that marks the heart of the Scorpion. To the right is Messier 4, a globular cluster of thousands of stars. Wrapping the entire field are shrouds of dust, reflecting the yellow light of Antares and the blue light of hotter stars above, such as Rho Ophiuchi at top right. Glowing hydrogen gas clouds add the magenta hues.

The remarkable feature of this field are the dark fingers, clouds of dark interstellar stardust glowing with a dim yellowy-brown hue. In places the clouds become more opaque and intense, blocking any light from background stars. Those clouds must be close by in our galactic spiral arm because few stars lie between us and their dark masses. Estimates put them about 400 light years away.

The entire region is a busy factory of star making, one of the closest to our Sun. Chances are our solar system formed in a similar star factory 5 billion years ago, one that has long since dissolved away and dispersed around the Galaxy.

Like the previous shot, this is a Canon 7D/135mm telephoto image in a stack of six 2-minute exposures, taken from Chile in early May. I find it remarkable that with digital cameras just 2-minute exposures not only bring out the dark nebulas, but actually show them with colour and tonality. In the old days, film shots 20 minutes long only ever showed them as a mass of underexposed and featureless black.

— Alan, June 16, 2011 / Image © 2011 Alan Dyer

Off the Stinger Stars of Scorpius

Off the tail of Scorpius lies one of the great starry regions of the Milky Way. From southern Canada the Scorpion’s Tail barely clears our horizon at this time of year, on June nights. But from farther south, Scorpius crawls high into the sky — and the sky actually gets dark at solstice, so stargazers can see the starclouds of Scorpius in all their glory.

At right, the blue stars mark the “stinger” at the end of the Scorpion’s tail. The brightest one, called Shaula, or Lambda Scorpii, is a hot blue giant star some 10,000 times more luminous than our own modest Sun. It is also a triple star, with another luminous blue star orbiting it, plus a third odd mystery star thought to be either a neutron star or perhaps a young proto-object still in the process of forming a proper “main-sequence” normal star.

To the left lie two prominent clusters of stars: at top the Butterfly Cluster (a.k.a. Messier 6), a bright group of stars sitting amid a dark bay of dust. Below it, almost lost in the stars, is Ptolemy’s Cluster (a.k.a. Messier 7), that is an obvious sight to the unaided eye – so obvious the Greek astronomer Ptolemy catalogued it in 130 AD. Several other star clusters pepper the field.

This telephoto lens shot frames the field as binoculars would show it. I took this from Chile in early May, using the Canon 7D and 135mm lens, for a stack of six 2-minute exposures at f/2.8 and ISO 1250.

— Alan, June 16, 2011 / Image © 2011 Alan Dyer



The Seven Sisters of the South

Down in the south sit many austral equivalents to namesake northern sky objects: the Southern Cross, the Southern Beehive, the Southern Pinwheel. This is the “Southern Pleiades,” a match to the famous Pleiades star cluster prominent in our northern hemisphere sky. Since our Pleiades also carries the moniker the “Seven Sisters,” I suppose that makes this object the “Seven Sisters of the South.”

The field here again duplicates what binoculars would show, and this is a lovely object for binos. Its resemblance to the northern Pleiades comes from this star cluster’s bright but scattered appearance, and the blue colour of its sorority of stars. Like its northern counterpart, the Southern Pleiades is a cluster of hot young stars which shine furiously blue in their energetic youth. This group is perhaps no more than 50 million years old, and like the northern Sisters, shines quite close by, just 480 light years away, putting it a stone’s throw away down our own galactic spiral arm.

Officially catalogued as IC 2602, and also dubbed the Theta Carinae Cluster, this clutch of blue stars shines just below the Carina Nebula (you can see both together in my earlier blog The Best Nebula in the Sky). A couple of other fainter star clusters also populate the field.

I took this shot with the Canon 7D and 135mm telephoto lens and stacked five 2-minute exposures. Stacking helps smooth out background noise, though in a wide field shot like this, the sheer number of stars tends to overwhelm any camera noise.

— Alan, June 4, 2011 / Image © 2011 Alan Dyer




An Island in a Sea of Stars

This image looks toward the inner spiral arm of our Milky Way called the Norma Arm, where stars bunch together to form the rich Norma Starcloud, a prominent patch in the southern Milky Way. What you see here is all stars, lots and lots of stars.

Seemingly embedded in the sea of stars is an island of brighter stars called the Norma star cluster, or more prosaically NGC 6067. It’s about 6800 light years away, much closer to us than the more distant stars behind it. It is literally floating in front of the background sea of stars.

As with the previous image, this is a wide field shot, taken with the 135mm telephoto, to frame the field much as it would appear in binoculars. This shot is a stack of six 2-minute unguided exposures at ISO 1250 with the Canon 7D riding on the little Kenko tracking platform. It’s one of a couple of dozen fields I shot the first night of shooting on Chile in May.

— Alan, June 4, 2011 / Image © 2011 Alan Dyer





Rose of the Southern Sky

It’s been a month since my last post, a month with no new astrophotos from home. But I’ve got a backlog of RAW files to work through from the Chile trip a month ago. Here’s a new image from that shooting expedition. It’s of an area of the southern sky that lends itself to every focal length and framing variation — you can’t go wrong with the Carina Nebula!

This wonderful nebula in the deep-south Milky Way rewards any astrophotographer. For this shot I used a 135mm telephoto (Canon’s wonderful f/2 L-series lens) and the Canon 7D camera. The 7D is what I call a “stock” camera, used just as it comes off the dealer shelf. The 7D does a superb job capturing the red nebulosity and its faint outlying bits and pieces. It tends to record these clouds of glowing hydrogen as magenta in tone. By comparison, my other Canon camera is a “filter-modified” 5D MkII. You can see a shot of this same area of sky taken with the 5D MkII a few blogs back under The Best Nebula in the Sky, posted May 6. The 5D MkII’s modification (which replaces the filter in front of the sensor with a new astro-friendly one) allows it to record deep-red wavelengths and picks up more faint nebulosity, registering it more as red in tone. But both images look good and presentable.

This field is rich in objects — not only the main sprawling nebula but nearby star clusters and patches of dark dust clouds. It is one of the finest fields in the sky for binoculars, and this shot approximates the field of view of typical binos. I like to shoot a lot of objects with telephoto lenses — while the main subject is not frame-filling and in your face, it does match (at least in field of view) what you can see in binos, useful for illustrations and observing articles. Of course, the camera picks up  more stuff and colours even your bino-aided eyes can’t see.

This shot is a stack of five 2-minute exposures at f/2.8 with the 135mm telephoto, on the Canon 7D at ISO 1250. I used the little Kenko Sky Memo tracking platform for this, letting it track without any added guiding. It’s tracking was spot on, with nary any star trailing as it followed the target for 20 minutes or so.

— Alan, June 3, 2011 / Image © 2011 Alan Dyer

Under the Southern Cross

I’m back home in Canada now, after 24 hours of travel from Chile. Despite having to check my carry-on bag filled with cameras and the Mac laptop for the Calama to Santiago domestic flight, all the gear arrived home intact. Now to process the 40+ gigs of images I shot. And properly reprocess some of the images worked on at the dining room table at the lodge, under the bright Chilean sun.

Here’s a shot taken the last night of shooting, of the icon of the southern sky, the Southern Cross, more formally called the constellation of Crux. Next to it, at left, are the dark clouds of the Coal Sack. To the eye, these clouds looks like a uniform dark spot in the sky. But photos, and even binoculars, reveal it as a complex mess of shapes and densities.

What stands out are the colours of the Cross stars. Most are hot blue Type B stars – energetic blue giants. But Gacrux at top is very red – it’s a cool red giant star.

Scattered amid the Cross are Coal Sack are several clumps of stars – open star clusters, such as the Jewel Box Cluster to the left and just below Becrux, the left star of the Cross. On our final night at the Atacama Lodge, we helped out at the lodge in a public stargazing session to a group of tourists from all over the world. I ran a telescope aimed at the Jewel Box and heard lots of ooohs and aaahs at the sight of its multicoloured stars.

This shot is a Mean-combine stack of five 3-minute exposures at f/2.8 with the wonderful Canon L-series 135mm telephoto, and the Canon 5D MkII camera, filter-modified, at ISO 800. The camera was on a Kenko SkyMemo tracking platform, which followed the stars during the 15 minutes worth of exposures.

– Alan, May 9, 2011 / Image © 2011 Alan Dyer

The Galactic Cathedral

We’re on our last full day in Chile, packing up and sorting out. I’ll finish off my Chile blog series with this parting shot — the entire southern Milky Way from horizon to horizon.

In this view, we’re looking straight up, with the horizon at the edges of the frame of the 15mm fish-eye lens. The glowing starclouds of Sagittarius and Scorpius, seen in close up in the previous blog post, are in the centre of the frame. The Southern Cross is at far right, the Northern Cross at far left.

This scene is a superb way to end a night of southern sky stargazing – just lying back and looking up at the entire panorama of the Galaxy. You really do get the sense that we are indeed living at the edge of the Galaxy, looking off into its bright core, and with its spiral arms wrapping around us.

It’s a galactic cathedral of stars.

– Alan, May 7, 2011 / Image  © 2011 Alan Dyer

The Starfields of Sagittarius and Scorpius

I can’t get enough of this region of sky. I can and do shoot this with every lens I have and with all kinds of framing (horizontally, vertically, or at a rakish angle, like here) and it always looks great.

These are the rich and stunning starfields toward the centre of the Milky Way in Sagittarius (bottom) and Scorpius (at top). Look for the pinkish nebulas dotted along the Milky Way, the bright starclouds, and the dark lanes of interstellar dust. It’s all part of the galactic recycling program that our Milky Way participates in, as stars explode, cast off dust and gas, which then clump into glowing nebulas and form new generations of stars.

I took this shot about 5 a.m. a couple of mornings ago, with this area directly overhead. It’s a stack of six 3-minute exposures with the 35mm lens and Canon 5D MkII camera. I took some shots through a soft focus filter to add the star glows.

– Alan, May 7, 2011 / Image © 2011 Alan Dyer

The Best Nebula in the Sky

What a great field this is to explore with binoculars. The image here takes in about the same area of sky as most binoculars and look what it contains! Arguably, the best nebula in the sky: the Carina Nebula, and the best open star cluster: the Football Cluster (aka NGC 3532) to the left of the main nebula. And then there’s the Southern Pleiades star cluster, IC 2602, below the nebula, and lots more besides.

This one field is reason enough to travel to the southern hemisphere for stargazing.

I shot this last night, May 6, 2011, using a 135mm telephoto lens at the modified Canon 5D MkII camera. The filter modification allows the camera to pick up a lot more of the faint wispy bits of glowing nebulosity. This is a stack of four 3-minute exposures, with two of the exposures shot through some thin cloud (the first we saw all week!), adding the subtle but photogenic glows around the stars.

– Alan, May 7, 2011 / Image © 2011 Alan Dyer

Dawn Planets, Part Two

I began my night sky shooting stint earlier this week in Chile with a shot of the dawn gathering of planets. I’ve ended it with another, taken this morning at 7 a.m., on May 7, 2011.

This scene shows four planets partaking in a rare close mutual conjunction in the morning sky. From top to bottom they are: Venus (brightest) with Mercury just to the right of Venus (both inner worlds appear close together for the next week or so), then below that pair, Jupiter, then at the bottom and faintest, Mars.

Notice how Venus, Jupiter and Mars are almost equally spaced, forming a straight line that defines the ecliptic path of the planets, here seen coming up vertically from the horizon. This is the view from 23° south latitude; from Canada these planets would be arrayed more horizontally low across the eastern horizon.

The conical peak at left is 5,900-metre-high Licancabur Volcano. The lights are tail lights of pre-dawn traffic going over the high pass over the Andes into Bolivia.

– Alan, May 7, 2011 / Image © 2011 Alan Dyer

Dawn’s Early Light

This shot took getting up early (rather than staying up all night) to shoot the sky at 5 a.m. The main subject here is a subtle tower of light rising up vertically from the eastern horizon. That’s the Zodiacal Light, best seen from low latitudes.

The glow is from sunlight reflected off dust particles deposited in the inner solar system by passing comets. While it looks like dawn twilight coming on, the light actually comes from out in space and heralds the brightening of the sky by true twilight.

After a week of gazing in the evening sky, a number of us observers took the opportunity this morning to snooze through part of the night and get up prior to dawn to see a new set of objects. At that time of night, and at this time of year, the centre of the Milky Way sits straight overhead, and shows up here in an ultrawide shot from horizon to zenith.

I shot this with the 15mm lens at f/2.8 and the Canon 5D MkII at ISO 800. It’s a stack of two 3-minute exposures.

– Alan, May 6, 2011 / Image © 2011 Alan Dyer

The Southern Crosses

The emblem of the southern hemisphere sky is here on the left: the Southern Cross, or Crux. But how many other crosses can you find in this field?

At the right is a larger version of Crux, made of two stars from Carina and two stars from Vela. So it’s not a proper constellation but an asterism well known in the southern hemisphere sky, called the False Cross.

You might also be able to pick out a third cross at lower centre, looking upside down but also made of four stars in an elongated diamond shape.

The prominent centre-stage object here is the massive Eta Carinae Nebula, sometimes just called the Carina Nebula (I’ve never determined what the proper and official name of it is). Surrounding it is an array of star clusters that make this area an absolute delight to explore with binoculars. But this week, at our stay at the Atacama Lodge, our small observing party has had fabulous views of the nebula in a big 18-inch telescope that reveals intricate structure in the swirls and eddies of its glowing clouds.

This is a stack of 6 exposures, each 3 minutes at f/4 with a 50mm Sigma lens and the Canon 5D MkII camera.

– Alan, May 6, 2011 / Image © 2011 Alan Dyer

Southern Spectacular

Everyone from the north who sees this area of sky for the first time quickly realizes just how much better the sky is down south. This is the most spectacular region of the deep-south Milky Way, as it passes through the constellations of Carina, Crux and Centaurus.

Dead centre here is the symbol of the southern sky, the Southern Cross. To the right of it glow the reddish nebulas of Carina and Centaurus; to the left of the Cross lie the dark clouds of the Coal Sack and the pair of brilliant stars, Alpha (on the left) and Beta Centauri. Alpha is the closest bright star to our solar system.

This one field contains much of what makes the southern sky so memorable and a mecca for any backyard astronomer. You haven’t lived an astronomical life until you’ve seen this part of the Milky Way, accessible only from southern latitudes.

I took this shot last night, May 4, 2011, using a Sigma 50mm lens and a modified Canon 5D MkII camera. The image is a stack of four 6-minute exposures at f/4 and ISO 800, plus a stack of two more 6-minute exposures taken through a soft-focus filter, with those images layered into the final Photoshop image to add the star glows and make the constellation outlines, like the Southern Cross, pop out.

– Alan, May 5, 2011 / Image © 2011 Alan Dyer

Exploring the Large Magellanic Cloud

A prime attraction of the southern hemisphere sky is an object called the Large Magellanic Cloud, a satellite galaxy to our own Milky Way, and only visible from southern latitudes. You can spend many nights just working your way through its confusing array of star  clusters and nebulas.

Here, Gary Finlay (seated) and Philip Downey (standing, checking his digital iPad star atlas) are doing just that – trying to identify the many objects you can see in one eyepiece field at a time. And the LMC is so large it covers dozens of eyepiece fields. They’re using an 18-inch reflector, which is providing us with outstanding views of not only the LMC and its many nebulas, but hundreds of other targets along the Milky Way.

I took this with a 30-second exposure at f/2.8 and ISO 3200 with the Canon 7D. The location is the small observing field adjacent to our rooms at the Atacama Lodge in Chile.

– Alan, May 4, 2011 / Image © Alan Dyer 2011

Toward the Centre of the Galaxy

This is without a doubt the most spectacular area of sky. Here we’re looking toward the centre of our Galaxy, toward the starfields of Scorpius (at right) and Sagittarius (bottom centre). The field is a riot of stars, dark lanes of dust, and patches of glowing red nebulas.

It is wonderful experience – wonder-filled! – just to lie back and scan these constellations with binoculars or a wide-field telescope. One outstanding feature are the parallel bands of dark dust that seem to form the shape of a dark prancing horse in the Milky Way.

The brightest area of the Milky Way here is the Sagittarius Starcloud, and marks the direction of the centre of our Galaxy. From here in Chile where I took this shot, this region of sky passes directly overhead, making it more prominent than at northern latitudes where the galactic core is often lost in horizon haze.

This image is a stack of four 6-minute exposures at f/4 with the 35mm lens and Canon 5D MkII camera. For one of the exposures I shot through a special soft-focus filter to add the fuzzy star glows that make it easier to see the outline of the constellations. The filter also emphasizes the colours of the stars.

The image is a segment of a 12-section panorama I shot all along the Milky Way from dusk to dawn.

– Alan, May 3, 2011 / Image © 2011 Alan Dyer

Entangled in Dark Dust

This is a star cluster in Scorpius called NGC 6124 – it doesn’t have a name, to the best of my knowledge. But a good one might be the “Dark River Cluster.”

I’ve shot lots of stuff along the Milky Way on my various trips to the southern hemisphere, but this field was a pleasant new surprise. While I had photographed this star cluster before, previous portraits had been extreme closeups. I had not shot it with a wide field like this.

The field here takes in about the same area of sky as binoculars. One of my projects on this current trip to Chile has been to shoot binocular fields like this. And it’s a good one. The cluster is a little off the beaten track in Scorpius and tends to be ignored. But its position entangled with lanes of dark nebulosity makes it a wonderful contrast of stars and darkness.

The dark lanes are obscuring dust in the foreground, hiding the light of distant stars in the Milky Way. The cluster itself is about 18,000 light years away, quite a distance for a star cluster, and putting it a good portion of the way toward the centre of the Galaxy.

For this shot I used the Canon 7D camera and 135mm telephoto, for a stack of six 2-minute exposures at ISO 800 and f/2.8.

– Alan, May 3, 2011 / Image © 2011 Alan Dyer


In the southern hemisphere sky we are treated to the stunning sight of the centre of the Galaxy rising each night, as the starfields of Scorpius and Sagittarius come up over the eastern horizon. In this shot, taken last night (May 2/3), we see the Milky Way’s heart rising behind some of the robotic, remotely-controlled domes and telescopes at the Atacama Lodge in Chile. Only the centre dome is operating, taking images or data under the command of someone half a world away.

Amazing technology to be sure, but … that robotic observer misses the experience of standing under the Milky Way, watching its heart rise over the Andes and swing overhead through the night. The Milky Way is so bright it lights the ground, as you can see here.

Last night our little group of 7 Canadian observers had a fantastic time exploring the southern sky with several telescopes, including an 18-inch reflector set up for us by lodge owner Alain Maury. With the help of a couple of wide-angle eyepieces we saw wonderful views of the Vela Supernova Remnant, dark nebulas in the Milky Way, and showpiece targets like Omega Centauri and the Tarantula Nebula – the list goes on! And will again tonight, as we compile another “hit-list” of targets to find tonight.

For this shot, I used the Canon 7D camera, a 15mm lens, and ISO 2500 for a 40 second exposure at f/2.8. This is one of about 500 frames taken for a time-lapse movie of “Galaxyrise.”

– Alan, May 3, 2011 / Image © 2011 Alan Dyer

A Dawn Gathering of Planets

The joys of stargazing at southern latitudes! Here’s a shot from this morning, May 2, 2011, of the gathering of four planets now coming together in the pre-dawn sky. From Canada, you won’t see this well at all. The planets will be hugging the horizon and lost in the twilight. But from here in Chile, at a latitude of 23° south, the planets are arranged vertically straight up from the horizon. Over the next couple of weeks the planets will converge as Venus and Mercury drop down to meet Jupiter and Mars – they’ll be tightest, within 6° of each other on the mornings of May 11 and 12, when Venus and Jupiter, the two brightest objects here, will be closest together.

It was very neat watching them rise this morning over the Andes, first brilliant Venus popping over the ridge, then fainter Mercury, the Jupiter, and finally, at the bottom here, Mars. Venus and Mercury pair at top, and Jupiter and Mars are together at bottom.

The conical peak at left is 5,900-metre (19,400-foot) Licancabur, an extinct volcano, one of many along the line of the Andes. I shot this from just outside our dining room at the Atacama Lodge near San Pedro de Atacama. It was the finale of an all-night session shooting the Milky Way in stills and time-lapse. All the gear worked great and the raw images look fabulous. More to come!

– Alan, May 2, 2011 / Image © 2011 Alan Dyer