SLOAN DIGITAL SKY SURVEY (SDSS) IMAGES
of astronomical deep sky objects
to approximately 14.5 magnitude
Choose from the menu at left or search for an SDSS image on Astronomerica below
- enter object name with space (e.g., ngc 3184)
Recent supernovae: NGC 4854, NGC 1084, NGC 4141 (2nd in less than a year), NGC 2765, UGC 5002, NGC 2545, MCG -2-1-14, NGC 3672, NGC 7321, UGC 5201, UGC 10155, NGC 5123, NGC 309, UGC 10261, UGC 4085, NGC 4226, UGC 9317, NGC 2618, UGC 10721, NGC 4490, NGC 4141, NGC 4273, NGC 3978, NGC 5829, NGC 4617, NGC 3499, UGC 7798, UGC 6109, NGC 4541, NGC 4036, MCG 2-39-21
This collection of images taken from the Sloan Digital Sky Survey is intended to serve as an observing reference for amateur astronomers. Images are grouped alphanumerically in pages indexed at left. Please select a page, then select an image from the thumbnails on that page. Or search directly for the object above. Note that only some objects in each catalog will be available due to the partial coverage of the survey.
It is often difficult to find images of lesser known or dimmer objects so you know what to look for in the telescope or if you wish to compare your view to an image to confirm what you are seeing. Any spot in the sky covered by the SDSS can be captured using their charting tool. I've saved you some time by capturing these objects with the SDSS charting tool and arranging them alphabetically for easy reference.
I've done my best to capture all the objects up to 14.5 magnitude that are available, but I'm sure I've missed some and I'm working to find those. Some dimmer objects are also included, especially those that are missing cataloged magnitudes or are doubtful, to assist you in determining if they are worthwhile targets. Most of the objects imaged by SDSS are galaxies and most are in the northern hemisphere. The imaging portion of the SDSS-II Legacy survey is complete with about one quarter of the sky imaged. The final data release available to the public was Data Release 7 from October 2008. More images will appear here as I locate ones that I've missed. (Nov. 6, 2008 note- I have begun adding the remaining images from all data releases.)
These images are all from the Sloan Digital Sky Survey. Unless otherwise indicated (e.g., "detail" or "wide field"), all fields are approximately 13.5 by 10 arcminutes, which equates more or less to a high power view in a typical amateur telescope using a non-wide field eyepiece. This gives you a sense of the relative size of the objects. The .jpg images are 1024 x 768 pixels and average about 50 KB each. They are sized slightly smaller to fit a web browser on a computer set to 1024 x 768 resolution, but retain the full resolution if downloaded. North is up and West is to the right in all images. In most images the object is centered. However, due to positional errors in the various catalogs, the object may sometimes be slightly off-center. In some cases, the object may not be within the field at all, but the image is provided anyway so you don't go crazy trying to find it at the cataloged position. Some artifacts of the imaging process and transient phenomena (color flares near stars, neon colored lines, and seams where images were patched together) are apparent in some images.
Visual magnitudes and positions (Right Ascension/Declination for Epoch 2000 and constellation abbreviations) are also provided (8 Nov 2008 note- making slow and intermittent progress. I am also correcting erroneous positions given by the catalogs based on comparison of the SDSS images to non-stellar objects from the Hubble Guide Star Catalog that represent the bright cores of galaxies). Visual magnitudes for the Messier and NGC objects are from the Historically Corrected New General Catalogue (TM) (HCNGC). Where PGC galaxies are identified, the blue magnitude is given, which generally is about .8 magnitude dimmer than the visual magnitude. In my own experience, I've noticed that, all else being equal, the bluer objects in SDSS images tend to be fainter visually than more yellow or white objects that appear to be of the same magnitude. Also remember that surface brightness has a big effect on your ability to see these objects well. An object with a lower magnitude number (brighter) but which is more "spread out" will be harder to see than some with higher (dimmer) magnitudes but which are more condensed. In some cases, the core may be quite stellar and easy to see, but the outer detail may be difficult or impossible visually. There's only one way to find out.
Most of these objects are identified with designations from the following catalogs in such a manner that you can get an idea of the relative difficulty of observation by the designation used. Many objects appear in multiple catalogs. In the case of the MCG and CGCG objects, these round out the more difficult galaxies that still rate their own pages. In addition, other dimmer field galaxies are identified by their Principal Galaxy Catalog (PGC) numbers. Miscellaneous planetaries and a few oddballs such as quasars are a bit of a grab bag. I find PGC numbers difficult to remember, so I use them as a last resort for galaxies. I even use SDSS or 2MASS survey designations occasionally if there's nothing else. I'm working on identifying field galaxies in each image up to 18th mag in the blue band given by the PGC. So for example, M51 is also NGC 5194, UGC 8493, MCG 8-25-12, and PGC 47404, but almost everyone refers to it as M51 (or "the Whirlpool Galaxy") because it's one of the brighter galaxies, therefore that's how it is identified here. The designations used here generally follow a pattern from brightest to dimmest as follows:
M = Messier Catalog, compiled by Charles Messier (many of the brightest objects - late 1700s)
NGC = New General Catalog of Nebulae and Clusters of Stars by John Dreyer (all known objects at the time, including galaxies, which were considered nebulae - late 1800s)
IC = Index Catalog of Nebulae compiled by John Dreyer (not all are nebulae; late 1800s-early 1900s)
UGC = Uppsala General Catalog of Galaxies compiled by P.N. Nilson in 1973
MCG = Morphological Catalog of Galaxies compiled by Vorontsov-Velyaminov and Arhipova at the Moscow State University in the 1960s. Many of the positions are slightly off and the magnitudes tend to be visually fainter than cataloged, so some of these are probably dimmer than 14.5 magnitude. The northern hemisphere MCG galaxies are listed first. Southern hemisphere MCG galaxies have a negative sign before the number, and are listed after their northern friends.
CGCG = Catalog of Galaxies and Clusters of Galaxies compiled by Fritz Zwicky. The individual galaxies tend to be quite small and dim. Most are not brighter than 14.5 mag visually. The magnitudes in the original catalog are photographic. Because the catalog may appear in recreational software charting programs, the brighter galaxies are included on Page 2. The positions are corrected for Epoch 2000.
For an extensive list of other astronomical object catalogs see http://www.seds.org/messier/xtra/supp/cats.html.
The image pages at left are arranged alpha-numerically by object name.
Funding for the Sloan Digital Sky Survey (SDSS) has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Aeronautics and Space Administration, the National Science Foundation, the U.S. Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. The SDSS Web site is http://www.sdss.org/.
The SDSS is managed by the Astrophysical Research Consortium (ARC) for the Participating Institutions. The Participating Institutions are The University of Chicago, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, University of Pittsburgh, Princeton University, the United States Naval Observatory, and the University of Washington.
Astronomerica is an independent site not affiliated with the Sloan Digital Sky Survey.
Deep sky images are provided as an observing aid to amateur astronomers - enjoy!