The Ghostly Glow of Gegenschein


Gegenschein from New Mexico (14mm 5DII)

The band of light at right is the familiar Milky Way. But what’s that faint stream of light to the left? It’s called the Gegenschein.

My last blog showed an image of the Zodiacal Light in the west. In fact, that glow extends up and continues all the way across the sky as a very faint stream of light at the threshold of vision called the Zodiacal Band. But at the place in the sky 180° opposite the Sun the Band intensifies to become a diffuse patch of light. It’s easy to see with the naked eye from a dark site if you know to look for it, and where it is likely to be. Last week, it was sitting below the constellation of Leo, in an area of sky that is pretty blank. So any faint glow stands out.

As with Zodiacal Light, what you are seeing is sunlight reflected off comet and asteroidal dust, but for the Gegenschein (German for “counterglow”) the light is coming from dust opposite the Sun that is scattering light back toward us and the Sun, mirror-like. The back-scattering effect makes the dust appear a little brighter at the point opposite the Sun.

Spring is a good time to spot the Gegenschein (true for the northern or southern hemisphere) as it then lies in a sparse area of sky away from the Milky Way. But you need a moonless sky and a dark site free of manmade light pollution. It and the fainter Zodiacal Band are among the sky’s most subtle sights. Again, Atmospheric Optics has more details.

A bonus with this shot are some short streaks of light below and to the right of the Gegenschein. I think those are from geostationary satellites flaring at the anti-solar point as they, too, acted as mirrors briefly catching the sunlight. Being geostationary – likely communications satellites you aimed fixed dishes at – they stayed still while the stars and tracking camera moved, and so created streaks.

– Alan, March 20, 2013 / © 2013 Alan Dyer

 

The Magnificent Milky Way


Sagittarius & Scorpius Over Adobe House (35mm 5DII)

What an amazing area of sky – the centre of the Galaxy hovering over the Earth below.

This was the scene two mornings ago, on our last clear night in New Mexico. This is what’s in the morning sky now and in the evening sky later in July and August. This is the area around Scorpius and Sagittarius and their rich star clouds toward the centre of the Milky Way.

It looks like a scene from an alien planet. But it’s here on Earth, gazing thousands of lights years toward the galactic core.

Enjoy!

– Alan, March 16, 2013 / © 2013 Alan Dyer

 

 

Orion and the Winter Triangle


Winter Triangle & Orion (35mm 5DII)

The Milky Way runs through the middle of the Winter Triangle, three of the bright stars of the northern winter sky.

At right is the familiar pattern of Orion the Hunter. But if you take his shoulder star, the orange-looking Betelgeuse, you can form an equilateral triangle with Sirius below centre and Procyon at upper left. The trio are sometimes called the Winter Triangle. The pattern seems obvious here but with so many other bright stars in the winter sky, I’ve never found the pattern too obvious. But in this image I’ve chosen to nicely centre and frame the Triangle.

I’ve also increased the contrast and saturation to emphasize the wealth of nebulosity that fills this area of the Milky Way. Streamers seem to reach out from Orion and connect to the reddish Seagull Nebula above Sirius, and also to the round Rosette Nebula above centre. The background sky west of the Milky Way under Orion is filled with a faint red glow, in contrast to the neutral black sky east (left) of the Milky Way.

I shot this last night, from New Mexico, on our last good clear night on a week-long observathon. This is a stack of 5 exposures, each 8 minutes long, plus two other exposures shot through a diffusion filter to add the glows around stars. I used a 35mm lens and a filter-modified Canon 5D MkII camera, riding on an iOptron Skytracker tracking platform.

– Alan, March 15, 2013 / © 2013 Alan Dyer

 

 

Celestial Scorpion in the Desert


Scorpius over Adobe House (35mm 5DII)

This is one of the few constellations that looks like what it is supposed to be – a desert-dwelling scorpion.

This is Scorpius in his native habitat of the desert. Here, from the latitude of southern New Mexico, he is standing on end, his claws at top, his curving tail and stinger at bottom.

The bright yellow star is Antares, the heart of the scorpion, embedded in a colourful mix of magenta, yellow and blue nebulas. Scattered along the Milky Way in the tail of the scorpion you can see several magenta emission nebulas shining by the combined red and blue light of hydrogen atoms.

What I love about this area of sky is the lacework of dark foreground nebulas, and the contrast between the bright star clouds and dark lanes of stardust. At centre left is the Dark Horse, the darkest part of which also carries the name Pipe Nebula.

I shot this image this morning at about 5 a.m, in the hour before the sky brightened with dawn twilight. This is a stack of seven 3-minute exposures with a 35mm lens, including two exposures taken through a diffusion filter to add the accentuated star glows. The ground details come from just one of the exposures.

As it’s been all week, the location is the Painted Pony Resort in southwest New Mexico.

– Alan, March 15, 2013 / © 2013 Alan Dyer

The Arch of the Milky Way


New Mexico Milky Way Panorama

On March evenings the Milky Way arches overhead in a magnificent river of starlight.

This is the panoramic view we are getting every night this week at our astronomy retreat in New Mexico, as we gaze upwards to the northern winter Milky Way running across the sky from northwest to southeast, from Cassiopeia at right to Vela at left.

In the middle you can see the stars of Orion and his familiar Belt.

On March nights we are gazing outward, to objects farther out than we are from the centre of our Galaxy. This part of the Milky Way is dominated by stars and nebulas around the Orion complex several hundred light years away.

Above the main house a pillar of light rises from the western horizon and tapers out as it reaches the Milky Way high in the west. That’s the Zodiacal Light caused by sunlight reflecting off comet dust in the inner solar system. You need to be at a fairly dark site to see it, with no prominent urban sky glows to the west. But springtime is the best season for seeing the Zodiacal Light in the evening sky. From the latitude of New Mexico the Zodiacal Light rises almost straight up, perpendicular to the horizon. Here, Jupiter sits at the apex of the Zodiacal Light.

So this panorama includes the Earth, objects in our solar system (Jupiter and comet dust), and the distant stars and nebulas of the Milky Way Galaxy we live in.

For this scene I shot a panorama of 4 segments, each consisting of 2 images stacked for noise smoothing, and the segments stitched with Photoshop. Each frame was a 3-minute exposure with the Samyang 14mm lens at f/2.8. The camera was on a tracking platform, so it followed the sky during the 25 minutes or so it took for me to shoot the entire panorama. I reframed the camera between each segment to try to get the horizon and landscape horizontal and lined up as best I could from segment to segment.

The ground is from one frame out of each segment and is blurred slightly because the camera was tracking the sky. Despite shooting a moving target, Photoshop was still able to automatically assemble the frames into a seamless panorama that, in this case, covers about 250°. This was the first time I attempted such a tracked panorama. I was impressed that it worked!

– Alan, March 14, 2013 / © 2013 Alan Dyer

 

A Comet and Earthlit Moon Amid the Stars


Comet PANSTARRS & the Moon (March 13, 2013)

This was the scene tonight, March 13, as Comet PANSTARRS set over the mountains in deep twilight, with the waxing Moon hanging overhead.

The small comet sits low in the orange glow of twilight, where the Moon was last night when it was down beside the comet. Tonight, a day later, the Moon appeared much higher in the sky as it waxes toward first quarter Moon in another few days. Tonight it was a crescent with most of the dark part of the lunar disk lit by Earthshine. I took this shot just before the comet set behind the mountains, to get the sky as dark as possible and the exposure longer to bring out some stars in the deepening blue of twilight.

I took this from the Painted Pony Resort in New Mexico where about 15 of us are gathered for a week-long star party and dusk to dawn “observathon.”

Indeed, I have to get back outside to continue shooting the Milky Way. It is another stunningly perfect night under New Mexico skies.

– Alan, March 13, 2013 / © 2013 Alan Dyer

 

Night of the Comet on a Desert Highway


Comet PANSTARRS & the Moon in Twilight (March 12, 2013)

Sometimes the best sky experiences just happen spontaneously. This was one of them – a night of the comet on a desert highway.

This was the scene at our impromptu roadside star party last night, north of the Painted Pony Resort in southwest New Mexico. About a dozen of us, mostly Canadians, gathered at a highway pull off to watch the unforgettable sight of the waxing crescent Moon setting alongside Comet PANSTARRS. You can see the comet to the left of the Moon in the background wide-field image, more or less as it appeared to the naked eye. But the real treat was the view through binoculars and my own small 80mm telescope. The series of closeups with a telephoto lens captures that view.

It was amazing to watch the comet tail and dark side of the Moon setting together as the last bits to disappear behind the mountains. All the while the winter stars and Milky Way were appearing overhead in a perfect sky, all on a mild desert night. A stunning astronomical experience.

Thank you PANSTARRS!

– Alan, March 13, 2013 / © 2013 Alan Dyer