Selected Astronomical Catalogues
and Online Data Services
-- and a Few Other Interesting Sites


As usual, I've had correspondence with Steve Gottlieb, Gary Kronk, Yann Pothier, Courtney Seligman, Brian Skiff, Sue French, and Wolfgang Steinicke on several interesting objects, and I've reconsidered a few of the puzzling cases myself. There is more detail on these in the NGC/IC introductory file available here and in the various Notes files.

My re-examination of the Galactic open clusters is continuing, and has become a part of a second sweep through the NGC (I have finished the NGC clusters) and IC in order to collect Gaia DR1 positions for as many objects as possible. The Gaia data have very small errors, 1.0 milliarcseconds or better claimed for stellar images, and surprisingly close to that for galaxy nuclei. However, as with most position data collected "automatically," those from Gaia sometimes refer not to the galaxy nuclei, but to superposed stars (e.g. NGC 354, NGC 380, NGC 561), "knots" (emission regions, clusters, etc.) in the galaxies (e.g. NGC 317), or are simply pulled off the nucleus by other bright features in the galaxy's image (e.g. NGC 499). So, each case must be considered individually, one by one by one ...

Courtney Seligman's comment to me about Pan-STARRS images last fall led me to look into the positions from DR1. Coincidentally, those became available at VizieR at about the same time. They are apparently tied very tightly to the Gaia DR1 astrometric reference frame as I have found it unusual to see disagreements between them of more than about 20-30 milliarcseconds. They still need to be checked against other positions for the same object, but they are clearly another excellent source of positions on the sky.

Finally, I have had a couple of requests for a "clean" list of the NGC and IC objects. This will not include the superposed and nearby stars or the "companion" objects. I am working on this list, and hope to have it ready for the next update of these files.

Here are some notes from previous releases of these files.

The Gaia DR1 data have a nominal epoch of 2015.0 and are largely without proper motions (proper motions are calculated only for the ~2.5 million objects in the Tycho and Hipparcos lists). Proper motions will be added in later data releases along with calculated J2000 positions. The recent epoch, of course, is not a problem for galaxies, but for the superposed stars, or for Galactic objects (e.g. asterisms, foreground stars, planetary nebulae), simply precessing the positions to 2000.0 will generally not yeild positions as accurate at the "standard" J2000.0 equinox and epoch as at the nominal epoch.

Brian Skiff and I have now selected accurate positions for all of the NGC and IC objects. These are in the current versions of my NGC/IC position and notes files available here, as are positions and notes for about 130 non-stellar objects (or objects thought to be non-stellar) that were known before the NGC was published, but not included in it.

There are still many checks to be done, and a full comparison with the original positions also remains. Finally, I am committed to providing data (particularly magnitudes and diameters) for all of the objects, too. So, check back now and then for updates. I'll announce them on the "amastro" mailing list as they become available, so you could check there as well.

The Revival of the NGC/IC Project

The NGC/IC Project web site disappeared from the web early in 2017. Fortunately, taking a cue from the constellation Phoenix, it is arising from the ashes of its former incarnation, this time guided by a team from The Astronomy Connection in the San Francisco Bay area. At the moment, the old site is again online pretty much as it existed earlier. It is not yet be fully functional as I write, but its main features are present. Eventually, a clean new site will be built around this humble revival. Please get in touch with me, Steve Gottlieb, Mark Wagner, John Pierce, or Akarsh Simha if you'd like more information. I'm pleased to say that we are also benefitting from advice and assistance from several others including Sue French, Brian Skiff, Andrew Pierce, and Wolfgang Steinicke.

Extragalactic Catalogues Maintained by Harold G. Corwin, Jr.

The copies of

  • The Third Reference Catalogue of Bright Galaxies, by G. de Vaucouleurs, A. de Vaucouleurs, H.G. Corwin, R.J. Buta, G. Paturel, and P. Fouqué
  • A Catalogue of Rich Clusters of Galaxies , by G.O. Abell, H.G. Corwin, and R.P. Olowin,
  • A Southern Galaxy Catalogue by H.G. Corwin, A. de Vaucouleurs, and G. de Vaucouleurs,
  • found here are corrected versions of the published catalogues. Though all three are available as printed and bound books, the electronic versions are preferred for reference as all known errata occuring in the printed versions have been corrected. Please let me know if you find any further errors.

    Brief explanations of the data are also available electronically; the full introductions with figures, tables, and references are only available in the printed versions.

    I am very saddened to note the death on 5 August 2017 of Professor Ronald P. Olowin, my valued colleague and friend, and co-author of the southern Abell Catalogue. Ron had been on the faculty at St. Mary's College in Moraga, California for 30 years. Among his many accomplishments at St. Mary's, he introduced astronomy to the curriculum, and spearheaded the building of the Geissberger Observatory on the College campus. Ron was 72. An obituary may be found at the St. Mary's College web site.

    A final version (1.4.3) of

  • A South-Equatorial Galaxy Catalogue by Harold G. Corwin, Jr. and Brian A. Skiff.
  • is also available. This has accurate positions, diameters, position angles, and de Vaucouleurs revised Hubble-Sandage (VRHS) types for 3333 single or multiple galaxies in the south-equatorial declination zones between +3 degrees and -21 degrees. The data were gleaned from POSS1 103a-O copy plates, then checked against the UKST IIIa-J portion of the DSS. The corrected position angles and VRHS types are published here in full for the first time. Notes on the individual objects are also available. SEGC provides a finding list for galaxies generally larger than about 1.8 arcmin at the 25.0 B-mag arcsec^-2 in the south-equatorial zone between the southern limit of the CGCG and UGC, and the northern limit of ESO-B, ESO-LV, and SGC. It provides a somewhat shallower coverage of this part of the sky than MCG.

    All of these catalogues are freely accessible; I and my coauthors ask only a reference and/or an acknowledgment if you use data from them.

    Links to Useful Astronomical Web Sites

    Most of these Web sites are devoted to astronomical cataloguing and data distribution.
  • NED -- NASA/IPAC Extragalactic Database
  • SkyView, a Virtual Observatory on the Web
  • The NASA Astrophysics Data System
  • MAST -- The Space Telescope Science Institute HST Data Archive
  • The Canadian Astronomy Data Centre
  • The ESO/ST-ECF Science Archive Facility
  • The NGC/IC Project
  • Wolfgang Steinicke's Home Page, with links to his historical work on the observations leading to the Dreyer's NGC and IC
  • Wolfgang Steinicke's biographical information for the NGC/IC observers
  • Courtney Seligman's Celestial Atlas featuring images and notes for many celestial objects, including the NGC and IC objects
  • Courtney Seligman's list of refrences and links to NGC/IC observer biographies and published papers
  • The Webb Deep Sky Society
  • Creative Commons
  • Miscellaneous Files

  • Links to Music Web Sites

  • ArkivMusic -- The Source for Classical Music is a clearing house for virtually all of the distributors of recorded classical music in the USA. I use their service frequently as it is fast and reliable. If there are problems (I've had just two in the past decade), their customer service reps will fix them quickly. They do downloads as well as physical media, and have begun a streaming service as well. They also have agreements with many record companies to make deleted issues available as on-demand CD-Rs.
  • Fanfare -- The Magazine for Serious Record Collectors. If you have any interest at all in listening to classical or jazz recordings, this magazine is for you. Published every two months, it is packed with reviews of most of the classical music recordings released in the US. The reviewers write knowledgeable and interesting reviews, and there is an on-line archive of the magazine's reviews and feature articles since it began publication in 1977.
  • The Havergal Brian Society promotes the music of the 20th century English composer and critic Havergal Brian. I must confess that I find his orchestral music fascinating and frustrating all at once. Tonally-based and superbly orchestrated, his music is nevertheless among the more difficult that I have tried to get a grip on. Brian's works overflow with ideas, and often burst through the usual formal constraints of symphonic music. The disconcerting result is that I am often lost among the trees while trying to make out the overall patterns of his wonderful forests of sound.
  • The Ralph Vaughan Williams Society. I had seen this Society mentioned in several of the music magazines I subscribe to, and had wondered at its intent. Vaughan Williams, after all, is -- along with Sir Edward Elgar -- the composer most responsible for the renaissance of English music in the first half of the 20th century. Many of his works are are among the greatest of that century, and are recorded frequently, so why does this Society exist? As it happens, Vaughan Williams's well-known music is just a portion of his considerable output over his long composing career (the 1890s until his death in 1958). The RVW Society promotes performances and recordings of Vaughan Williams's lesser-known music -- some never performed before -- and has issued thirty (so far!) recordings on its own "Albion" label. "Vaughan Williams," by the way is an unhyphenated double last name; others like it (e.g. "Maxwell Davies") are relatively common in Great Britain.
  • The Buffalo Philharmonic Orchestra is our orchestra. While perhaps not quite in the top rank of orchestras in the world, the BPO is very close, and we are lucky to be living in a city that supports them. They have many recordings available, most with their long-time conductor JoAnn Falletta, that demonstrate their versatility. In my opinion, almost all of the recordings are worth adding to your collection. Buying the recordings directly from the BPO makes a contribution to the orchestra as well as providing you with a fine CD.
  • Links to Railroading Web Sites

  • Amtrak -- the National Railroad Passenger Corporation provides intercity passenger train service in the US. We are fortunate to have an Amtrak station within a few miles of our home, so we travel by train when we can.
  • the Rail Passengers Association (formerly NARP -- the National Association of Railroad Passengers) is a primary voice in Washington, DC speaking on behalf of train and rail transit passengers. NARP has some considerable clout in helping to keep Amtrak going.
  • ESPA -- the Empire State Passengers Association has moved its main web presence to Facebook. Just as NARP is an organization devoted to promoting rail travel across the United States, so is ESPA "working for better rail passenger service and public transportation in New York State." In principle, ESPA promotes transportation initiatives across the entire state, but it seems to be primarily focused on Upstate issues affecting passenger travel outside the New York City area.
  • Southern Pacific Historical & Technical Society is dedicated to preserving and disseminating the historical record of the Southern Pacific Railroad and its affiliates. The Southern Pacific was "my" childhood railroad in California, and I renewed my attachment to it during my twenty years there between 1991 and 2011. SPH&TS publishes "SP Trainline" four times a year. Yes, the magazine is a nostalgia trip for me, with a strong focus on the railroad itself. But the "Espee" is also an important element in the history of the western and southwestern United States. "Trainline" often provides that broader context.
  • Model Railroading is a glimpse inside the mind of an atypical model railroader. I call myself "atypical" because I have no layout where I can actually run my trains, and no large space where I can even contemplate building such a layout. Nevertheless, I have a lot of rolling stock, almost all modeled from Southern Pacific prototypes (see above) or from Amtrak prototypes (also see above). Once in a while, I will report on my model railroading activity in this space. At the moment, this directory has before and after photos of an HO model of a single Amtrak passenger car that I've recently modified, as well as a link to a photo of the prototype.

  • Contact


    Note that I have closed my gmail account. Please use the above email address instead. Thanks!


    The previous version of this site was made possible by the Infrared Processing and Analysis Center, which is operated by the Jet Propulsion Laboratory and the California Institute of Technology, under contract with the National Aeronautics and Space Administration. I am pleased to acknowledge their support prior to my retirement in July 2011.

    NED maintains that earlier version of this site which will serve as an archival snapshot of the catalogues as they existed when I loaded them into NED.

    I use GoDaddy for hosting and domain services. They offer far more than I need, but what I do need from them is easy to use and reliable.

    Latest update: 28 January 2018