Spiral UGC 6903

UGC 6903 is a diffuse low surface brightness SB(s)cd galaxy in Virgo. The galaxy has an out of focus look to it with all its features being very soft and fuzzy. I'm used to sharp detail even in low surface brightness galaxies with reasonable seeing as I had but that isn't true with this galaxy. It is not part of the main Virgo Cluster as it lies some 100 million light-years distant while the core of the cluster is only about 60 million light-years away. The galaxy is about 70,000 light-years across.

There were 4 asteroids in the image, one hiding in front of the galaxy but it fell in a dark lane so was barely visible. Northeast of the galaxy is a galaxy cluster. NED shows its Bright Cluster Galaxy at a different location than the cluster itself. There is what also could be called a Bright Cluster Galaxy at its location but it has no redshift. That of the cluster is photographic but is in close agreement to the spectroscopic redshift for the BCG below it.

The annotated image contains many galaxies from the GAMA catalog. That stands for the Galaxy and Mass Assembly Survey. You can read about it he http://ned.ipac.caltech.edu/cgi-bin/...NRAS.413..971D

I had to use this catalog to get names that weren't just positional (usually from the SLOAN survey). My fall back for this had been the ASK, Automatic Spectroscopic K-means-based classification, but that wasn't available for many of the galaxies in this image. For more on this see: http://iopscience.iop.org/0004-637X/714/1/487 . Positional names are lengthy and clutter an image unless there aren't many objects to identify in the image so I usually avoid them when possible. Instead I use G for galaxies and Q for quasars when positional names are all that are available. UvES is used in this post for candidate quasars that NED lists under this designation. There are several in this image.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick