NGC891 is a perfect example of an "edge-on" spiral galaxy, meaning that it is a galaxy parallel to our line of sight. Think of it as a bicycle wheel moving away from you. It is located in the constellation Andromeda, not far from the large Andromeda Galaxy (M31) and very near the famous double star Gamma Andromedae.
This is an impressive object in my 18" dobsonian telescope, appearing as a large, gray needle with a denser core and some mottling along the edge. However, even a few seconds of exposure with a CCD camera reveals vastly more detail than what can be seen with a large telescope.
Note in particular the dark mottling along the middle of this object. This represents dust lanes in the galaxy's spiral arms.
Here's an important point to keep in mind when observing images of galaxies. In the same field as the galaxy you will see many individual stars. These are all located within our own Milky Way galaxy. You are looking "through" our galaxy, and its billions of stars, through the abyss of intergalactic space to the galaxy you see in the image. It was not until the 1920s that astronomer Edwin Hubble discovered that galaxies actually are separate islands of stars separated from our galaxy by incomprehensible distances, rather than small clouds (nebulae) in our own galaxy.
"Edge-on" Spiral Galaxy NGC891
Date Taken:October 9, 2010
Location Taken: Conditions of Location:FWHM 1.8
Equipment Used:14.5" Ritchey-Chretien telescope, SBIG STL11000 CCD camera, Astrodon RGB filters, TCC, PIR, remote guide head used with Takahashi Sky90 for autoguiding, T-Point used for polar alignment (required for each imaging session due to my portable setup)
Processing Used:9 x 600 seconds luminance, 6 x 300 seconds RGB, guided, 1x1 binning, processed in Maxim DL and Photoshop (total exposure 3 hours)
Distance from Location:10 Million Light Years
Constellation:Andromeda (mythological daughter of Cepheus and Cassiopeia)
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