The Milky Way from Down Under


15mm Ultrawide Southern Milky Way (March 2014)

The Milky Way of the southern hemisphere arches across the sky from the Southern Cross to Orion.

I’ve arrived at my dark sky site near Coonabarabran, Australia, with a very clear night to start my two-week session under the southern stars. Tonight I had just a 2-hour window between end of twilight and moonrise. But I made good use of it by taking some ultra-wide-angle views of the Milky Way we never see from up north.

This horizon-to-horizon scene looks straight up and stretches from the Southern Cross at far left (in the east) through Vela and Puppis to Orion at right (in the west). This sweep includes much of the Milky Way forever below our horizon from northern latitudes. At centre is the wide loop of the Gum Nebula. At lower left is the Large Magellanic Cloud, a satellite galaxy of the Milky Way.

At upper right is Jupiter in Gemini. The two bright stars near the centre are Canopus (left of centre) and Sirius (right of centre).

This is a stack of five 5-minute exposures at f/4 with the 15mm full-frame fish-eye lens on the Canon 5D MkII at ISO 1000. The camera was on the iOptron Skytracker, its first time in the southern hemisphere and my first time aligning it on the South Celestial Pole. It took a few minutes but I got it! The tracker worked great.

The forecast is for clouds and rain the next few days. But I’m here for over two weeks, and the weather can’t be any worse than it was in 2010 when the area was flooding. So with luck there will be more images to come from down under.

– Alan, March 21, 2014 / © 2014 Alan Dyer

Catching the Zodiacal Light


Zodiacal Light (Southern Spring Evening)

From a truly dark sky site, subtle sky glows become obvious. This is the Zodiacal Light of evening.

The Sun has long set and the very last glow of twilight is colouring the sky just above the hills. But reaching up from the sunset point in the northwest is a long triangular glow extending far to the south. This is called the Zodiacal Light – it does not originate in our atmosphere but is from sunlight reflecting off comet dust orbiting the inner solar system in the same plane as Earth’s orbit. Or at least that’s where we see it appearing the brightest, as a glow brightest near the Sun and extending along the ecliptic plane, where we find the constellations of the Zodiac. Here it appears in Capricornus and Aquarius.

I shot this two nights ago, from Coonabarabran, Australia, so the orientation of the Zodiacal Light is different from what we see from the Northern Hemisphere. Here it extends up from left to right. From home in Canada – and you can see the Light from northern latitudes on a dark night – it would be angled up from right to left, a mirror image of what we see here.

The subtle glow of Zodiacal Light is best seen in the evening sky in spring, no matter your hemisphere. I took this on December 6, 2012, still officially spring in the southern hemisphere if you assume southern summer starts on the solstice, December 21. However, Australians say summer begins December 1, so this is a portrait of the Zodiacal Light on a warm summer evening down under.

– Alan, December 8, 2012 / © 2012 Alan Dyer

 

Depth of Detail in the Large Magellanic Cloud


Large Magellanic Cloud (135mm)

If this was the only unique object in the southern sky that we couldn’t see from up North, then it would still be worth travelling south of the equator to see the southern sky.

This is the Large Magellanic Cloud, a satellite galaxy to our Milky Way. Being “just” 160,000 light years away (as opposed to millions of light years for most galaxies) this object is large (it fills the field of binoculars) and is rich in detail. Just look at all the pinkish nebulas dotting its ragged structure. The biggest is near the bottom, the massive Tarantula Nebula. Through a telescope there is so much to see in this object it takes careful comparisons with charts and atlases over several nights just to figure out what all the nebulas and clusters are in the eyepiece. It is a deep-sky observer’s dream object. While several professional astronomers have made their careers studying just the Magellanic Clouds.

Once classed as an irregular, ragged galaxy, the “LMC” is now thought of as a barred spiral. I think this photo suggests the two spiral arms coming off the top and bottom of the central elongated bar.

I shot this last night, under a perfect night of viewing in Coonabarabran, Australia, using a 135mm telephoto lens. The field is similar to what you see in binoculars though the long exposure (this is a stack of ten 5-minute tracked exposures) brings out more detail than the eye can see. Compare this wide view with a higher magnification shot I took two years ago from the same location. Both are good but I like this wider view better as it sets this big object into the celestial frame of the surrounding night sky.

– Alan, December 6, 2012 / © 2012 Alan Dyer

Cottage Under the Southern Stars


Timor Cottage & Magellanic Clouds

 

Here’s what heaven on Earth looks like to an amateur astronomer.

It’s a cottage all to myself under some of the darkest skies on Earth, and in the southern hemisphere where all the best stuff is in the sky. This is Timor Cottage near Coonabarabran, NSW, Australia, the self-proclaimed Astronomy Capital of Australia. Near Coona sits Siding Spring Observatory, home to Australia’s largest collection of optical research telescopes. I’m staying nearby, at this cottage under the stars doing my own southern sky explorations.

I was here in December 2010 but had to contend with torrential rains and floods two years ago. As you can see, the weather is much better in 2012!

This is a one minute exposure looking south, toward the most prominent objects in the southern evening sky at this time of year: the two Magellanic Clouds. They look like detached parts of the Milky Way but are separate dwarf galaxies orbiting our Galaxy and in the process of being ripped apart by our Galaxy’s tidal forces.

The red light at left is my other camera taking a shot of the Clouds through a telescope, the subject of my next blog.

It’s a perfect night when the only clouds in the sky are the Magellanic Clouds!

– Alan, December 6, 2012 / © 2012 Alan Dyer