The Princess Stars


Andromeda (50mm 5DII)

The stars of Andromeda the Princess highlight the autumn sky.

Here’s an image from last night, October 4, that frames all of the constellation of Andromeda, now high in the northern autumn sky. A trio of coloured stars arcs across the centre of the image, forming the main pattern in Andromeda. In Greek legend she was the daughter of Queen Cassiopeia and was rescued by Perseus from the devouring jaws of Cetus the Sea Monster.

Above the centre star lies the constellation’s most famous feature, the Andromeda Galaxy, shining at us from 2.5 million light years away. It is the most distant object easily visible to the unaided eye.

An equal distance below the centre star of Andromeda you can see another smaller fuzzy spot. That’s the Pinwheel or Triangulum Galaxy, a dwarf spiral 2.8 million light years away, but also a member of the Local Group of galaxies that contains our Milky Way and Andromeda as its two main members.

At left, just below centre, is a large open cluster of stars, NGC 752, easily visible to the naked eye.

For this shot, as I do for most constellation portraits, I used Photoshop to layer in a shot taken through a diffusion filter (the Kenko Softon A) on top of a stack of shots taken without the filter. This allows me to add the enhanced glows around stars to bring out their colours, and to do so in a controlled fashion by varying the opacity of the filtered view. Shooting on a night with high haze or cirrus clouds has the same end effect but that’s hardly a reliable way to take constellation images. Combining filtered and unfiltered views works great, and gives the “look” made popular years ago by Japanese astrophotographer Akira Fuji.

– Alan, October 5, 2013 / © 2013 Alan Dyer

 

Set the Controls for Triangulum


 

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