A Crisp Winter’s Night Under the Stars

Fish-Eye Winter Sky (8mm 5DII) (Feb 7, 2013)

It was crisp and frosty night filled with the bright stars of winter, and the Milky Way.

This was the sky from my backyard on Thursday, February 7, with Orion and his friends shining due south. It is a “fish-eye” shot taking in all of the sky from horizon to horizon. South is at bottom, north to the top. West is at right, east to the left.

The Milky Way runs from northwest, at top right, to southeast, at bottom left. When we look at this section of the Milky Way we are looking in the direction opposite the galactic core, toward the outer arms of our Galaxy.

Jupiter is the brightest “star” in the image, shining in Taurus. Rising out of the sky glow from towns to the west of me is the pillar of light called the Zodiacal Light. I think you can follow it stretching all the way across the sky from right to left (west to east) where it then becomes a subtle bright patch in the sky well east of the Milky Way. That’s the Gegenschein, a glow of light exactly opposite the Sun. It and the Zodiacal Light are caused by sunlight reflecting off comet dust in the inner solar system.

A night when you can see the Zodiacal Light and Gegenschein – they were visible to the unaided eye – is a good night indeed. Too bad this one was spoiled by some cloud and haze, reflecting the toxic yellow glow of ever-intruding sodium vapour lights.

Silhouetted in the sky glow at right is one of my telescopes, with camera #2 dutifully taking a closeup image of Orion’s Belt. That picture will be the subject of tomorrow’s blog!

– Alan, February 8, 2013 / © 2013 Alan Dyer

Snapshots of Starlife

IC 443 Jellyfish Nebula & M35 (92mm 6D)

This one image frames examples of both the beginning and end points of a star’s life.

I shot this last night, February 6, 2013, capturing a field in the constellation of Gemini the twins. At upper right is the showpiece star cluster known as Messier 35. It’s a collection of fairly young stars still hanging around together after forming from a cloud of interstellar gas tens of millions of years ago. M35 lies about 2,800 light years from Earth, on the other side of the spiral arm we live in. Just below M35 you can see another smaller and denser cluster. That’s NGC 2158, about five times farther away from us, thus its smaller apparent size. Both are objects that represent the early stages of a star’s life.

At lower left is an object known as the Jellyfish Nebula, for obvious reasons. The official name is IC 443. It’s the expanding remains of a star that blew up as a supernova anywhere from 3,000 to 30,000 years ago. What’s left of the star’s core can still be detected as a spinning neutron star. You need a radio telescope to see that object, but the blasted remains of the star’s outer layers can be seen through a large backyard telescope as a shell of gas. It is expanding into the space between stars – the interstellar medium – ploughing into other gas clouds. The shockwave from its collision with other nebulas may trigger those clouds to collapse and form clusters of new stars. And so it goes in the Galaxy.

For this portrait of stellar lifestyles, I used a 92mm apochromatic refractor and a new Canon 6D camera, one that has had its sensor filter modified to accept a greater range of deep red light emitted by hydrogen nebulas. The image is actually a stack of 12 exposures with an accumulated exposure time of 80 minutes.

– Alan, February 7, 2013 / © 2013 Alan Dyer

Constellation of the Queen

Cassiopeia (135mm 5DII)

After the 7 stars of the Big Dipper and the 3 stars of Orion’s Belt, these 5 stars are likely the most well-known in the northern sky.

These are the 5 bright stars of Cassiopeia the queen, better known simply as “the W” in the sky. Her five stars come in a range of colours, from blue giant Segin at upper left to yellow giant Shedar at lower right.

Scattered around Cassiopeia you can also spot at least one bright red nebula, the “Pacman Nebula,” plus a faint patch of purple nebulosity just above central Navi, the middle star of the W also known as Gamma Cassiopeiae. A few wisps of fainter reddish nebulosity and lanes of dark dust wind around the queen’s celestial throne. The left side of the W – the back of the throne –  is also home to several clumps of stars, nice open clusters suitable for binoculars or any telescope.

I shot this portrait of the Queen on Wednesday night, February 6, on a cool and frosty winter night in my backyard. For the set of 8 images that went into this stack I used a new tracking device, the iOptron SkyTracker. It’s a nifty little battery-powered tracker, compact but very solid. And it tracks very well. For this portrait I used a 135mm telephoto lens, and most, though not all, shots were very well tracked with pinpoint stars. A few frames showed a bit of trailing, not unusual for small portable tracking mounts. At $400 the little iOptron SkyTracker is a great accessory for anyone wanting to shoot constellations and the Milky Way with wide-angle to telephoto lenses.

– Alan, February 7, 2013 / © 2013 Alan Dyer

The Natural Naked-Eye Milky Way

Centre of the Milky Way Panorama (2011)

In this image I’ve tried to render the Milky Way in a view that simulates what you see with your unaided eyes.

The result is a celestial portrait in subtle shades of black and white.

This is a photo mosaic, but processed contrary to the usual methods – eliminating colour rather than enhancing it, and reducing contrast rather than boosting it. The result is a view that I think quite nicely matches what your eyes see, though certainly from a dark site. And in this case, you would need to be in the southern hemisphere to see this sweep of the Milky Way, from Aquila at left, to the Southern Cross at right, with the bright star clouds around the centre of the Galaxy in Sagittarius and Scorpius in the middle.

I’ve removed colours except for the muted colours of stars. And I’ve tried to render the stars with an intensity and dynamic range that the eye sees but that is often lost in long exposures.

The dark lanes of dust seen here really do look like this under dark skies. The nearby Coal Sack next to the Southern Cross does look a little darker than the rest of the sky. This view also captures another effect you can see in the real sky – the brighter sky below the Milky Way plane beneath Sagittarius and Aquila – there are more stars there, which make the background sky brighter than above the Milky Way plane (along the top of the photo) where the sky is permeated by dark obscuring dust.

This scene also frames the “dark Emu” – the shape drawn in the dark lanes that looks like a flightless emu in the sky. It’s an important “constellation” in Aboriginal mythology in Australia. The emu’s head is the Coal Sack at far right, her neck the long dark lane curving up through Centaurus and Lupus, and her tail the dark lanes at left in Ophiuchus, Scutum and Aquila.

I shot the original images for this panoramic mosaic in Chile in May 2011. You can see the full colour version in my “Milky Way Mosaic” post from 2011. The colours are wonderful. But there’s something enthralling about “capturing” the view more as your eyes – and mind – remember it.

– Alan, February 3, 2013 / © 2013 Alan Dyer