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
Some 3 billion years from now we are going to collide with this galaxy.
This is the famous Andromeda Galaxy, now 2.5 million light years from us but getting closer by the day! Andromeda, a.k.a. Messier 31, is the most distant object readily visible to the naked eye. It now shines high overhead for us in the northern hemisphere.
I asked Siri, my iPad assistant, how many stars are in the Andromeda Galaxy, and she said one trillion. She’s right. Recent estimates put Andromeda’s stellar population at 3 or 4 times that of our own Milky Way Galaxy. It’s also bigger. Measuring from the outermost extremities of the disk gives a diameter of over 200,000 light years, twice the size of our home galaxy.
I took this shot last week. It’s stack of five 15-minute exposures with a new Lunt 80mm refractor. The long exposures bring out the faint halo of stars extending beyond the main bright disk, the part you see in a telescope. You can also see Andromeda’s two close companion galaxies: M32, looking like a fuzzy star below the core; and M110, the elliptical galaxy above the core and connected to the main galaxy by a bridge of faint stars.
– Alan, September 27, 2012 / © 2012 Alan Dyer
OK, it’s just a dot. But that dot is a massive star ending its life in a titanic supernova explosion.
Unlike all the other stars in this picture, which are close by in the foreground of our own Milky Way Galaxy, that one star indicated is 38 million light years away. It lies in another galaxy altogether, in the outer spiral arm of the galaxy M95. Discovered on March 16, Supernova SN 2012aw is now shining with the light of a hundred million suns as it blasts most of its starstuff into space.
It is these types of stellar explosions that seed the universe with the elements heavier than lead.
I took this shot Monday, April 9 through my 5-inch refractor, an instrument not ideally suited for shooting small objects like galaxies. But its wider field here does take in not just M95 but also its companion in space, the spiral M96 at left. Both are barred spiral galaxies in Leo, on the list of targets compiled by Charles Messier in the late 18th century and favourites of backyard astronomers. It’s rare to get a supernova as bright as this (anyone with a modest telescope can see it) letting off in a well-known “top 100” galaxy like M95.
Take a look on the next clear night, and contemplate the cosmic forces at work to make visible a single star across a gulf of 38 million light years.
— Alan, April 10, 2012 / © 2012 Alan Dyer
Spiral galaxies are icons of deep space. This one is a classic. This is the Triangulum Galaxy, named for its home constellation. Amateur astronomers also know it as M33, the 33rd entry in Charles Messier’s catalog of deep sky objects compiled in the 1780s. To Messier, object #33 was another fuzzy spot he and others might confuse for comets, the objects astronomers of the day were really after.
It wasn’t until 1850 that the Earl of Rosse, observing with his monster Leviathan of Parsonstown, a 72-inch reflector telescope, managed to see M33 as something more than a nebulous glow. He saw what the photo clearly shows — spiral arms swirling around a central core. However, in those days, such “spiral nebulae” were thought to be whirlpools of gas where stars and solar systems were forming.
It wasn’t until the 1920s, with the work of Edwin Hubble, that objects like M33 were proven to be other galaxies like our Milky Way, each composed of billions of stars.
We now know the Triangulum Galaxy lies about 3 million light years away, and is about half the size of our Milky Way. That makes it the third largest member of our Local Group of galaxies, after our own Milky Way and the famous Andromeda Galaxy.
For this shot of M33, taken September 25, I stacked 6 images, each a 12-minute exposure at ISO 800 and f/6, shot with my Astro-Physics 130mm refractor and Canon 7D camera. Visible along the galaxy’s spiral arms you can see some of the reddish and cyan-coloured nebulas that are sites of active star formation in M33.
— Alan, Oct 7, 2011 / Image © 2011 Alan Dyer