In this part of the sky the Milky Way takes on a surprising palette of hues. And it’s all due to dust.
The centrepiece of this shot is a bright star cloud in Sagittarius called, well, the Sagittarius Star Cloud! But not the Large one. This is the Small Sagittarius Star Cloud, a.k.a. Messier 24, a mass of stars with a single black eye. The dark spot, called Barnard 92, is a dense and opaque cloud of dust. Stardust — clouds of carbon soot blown out by aging stars — weaves all through this scene, creating the dark canyons winding through the stars. Obscuring dust also dims much of the background stars and discolours most of this part of the Milky Way a yellowish brown. It’s the same effect that dims the setting Sun a deep orange or red, as its light shines through haze and dust in the sky.
But here, the Star Cloud looks bluish and “cleaner.” That part of the Milky Way has less dust in front of it. And yet it is much farther away than the yellow dusty starfields around it. When we look toward the Small Sagittarius Star Cloud we are looking through a dust-free window, allowing us to see unencumbered right past our Galaxy’s nearby Sagittarius-Carina spiral arm to glimpse a dense part of the more distant Norma Arm, an inner spiral arm of our Milky Way Galaxy about 12,000 to 16,000 light years away.
To the lower right of M24 is M23, a rich cluster of stars 2,000 light years away, nearby by galactic standards, and so sits suspended in front of the fainter star background. The pinkish nebula at top is Messier 17, the Swan Nebula.
I took this shot May 2 from Chile, using the Canon 7D and 135 lens, for a stack of six 2-minute exposures.
— Alan, June 7, 2011 / Image © 2011 Alan Dyer
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
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
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