If you like imaging galaxies that contain one or more ring structures, try "The Catalog of Southern Ringed Galaxies"(the CSRG) by Ron Buta.
The variety of rings and bars that are found in galaxies has been thoroughly explored and characterized by Ron Buta, and because of the complexity of these phenomena, it can be a bit tough to figure out what the galaxy classifications and the descriptive notes mean, for each and every galaxy in this catalogue.
(Each galaxy is classified and characterized using an elaborate descriptive scheme. )
(If you want some help, I can sort it out for you!)
If I ever get "a Round Tuit" I shall prepare, for iceinspace, an illustrated guide to the various types of ring structures that are found in galaxies.
The literature reference for this catalog is:
(1995), ApJS,
96, 39
and one good way to get the catalog is to access Buta's webpage:
http://bama.ua.edu/~rbuta/csrg/csrg.html
and then follow the link(s) to the catalog from this webpage.
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Another way to access this catalog is to use the "Vizier" service at CDS :
http://vizier.u-strasbg.fr
You put in "CSRG" into the search field in order to find the catalogue, and then you can find the catalog entry for any galaxy of interest.
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