A one hour exposure with an SBIG STL 1301E camera thru Kopernik's
20-inch F/8.1 telescope. The field of view is about 12x15 arc minutes with
North at the top. The image below is a negative with the galaxies identified.
A one hour exposure with an SBIG STL 1301E camera thru Kopernik's
20-inch F/8.1 telescope. The field of view is about 12x15 arc minutes with
North at the top. The image below is a negative with the galaxies identified.
A negative version of our image with the galaxies identified.
The "NGC Objects" in gray/underlined are stars or double stars,
not galaxies. The errors in the NGC catalog go back to the 19th Century.
NGC 7331 is the brightest galaxy in Pegasus. This spiral galaxy was one of William Herschel's earliest discoveries over 200 years ago. Although visible in large binoculars, it was missed by Messier. In many respects this galaxy resembles the famous, much-elongated, Andromeda Galaxy, M-31. This appearance is caused by its nearly edge-on alignment. NGC 7331 is rich in H-II (glowing Hydrogen/star forming) regions, similar to M-42 in our Milky Way Galaxy.
Early observers of the 18th and 19th centuries classified what we now know are galaxies as "spiral nebulae". They noticed that these "spiral nebulae" are often accompanied by smaller, fainter neighbors. NGC 7331 is no exception. Various 19th Century observers reported the presence of eight suspected companions. Modern observations support the likelihood of a true galaxy cluster in the background, but NGC 7331 is probably not involved, and is much closer to us. Modern images show that five of the eight "companions" are really just mis-identified stars or double stars. This error perhaps results from the poor telescopes used by the early observers. In addition to the true NGC galaxies in the image above, there is also a dimmer anonymous galaxy that is sometimes considered NGC 7325.
Radio emissions from the NGC 7331 area seem to engulf the nearby galaxy cluster, Stephan's Quintet, located about 1.5 degrees to the southwest. This, along with evidence of a very faint filament of material stretching between Stephan's Quintet and NGC 7331, argues for a past gravitational interaction. NGC 7320, the largest member of the Quintet, lies in the foreground of its more distant members, and is the most likely candidate for an ancient association with NGC 7331.
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Classification: Spiral Galaxy |
Classification: Lenticular Galaxy |
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Classification: Lenticular Galaxy -(uncertain) |
Classification: Barred Spiral Galaxy |
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Classification: Galaxy - type unknown |
Classification: All where
mis-classified as Galaxies |
George Normandin, KAS
October 28th, 2008