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


I have downloaded Gaia DR2 positions for all of the NGC/IC objects for which they are available and appropriate. I used a one-arcsecond search radius around the positions previously selected by Brian Skiff and myself, so if that position was in error by more than an arcsecond, an accurate Gaia DR2 position would not match. I'll clean these up as I check through the position files over the next few months.

I have finished merging these Gaia DR2 positions into the position files, so I am pleased to say that the identification and position-determination phases of the NGC and IC project on which I embarked 40-odd years ago is essentially complete. A few objects may still, of course, be wrongly identified, or have poor coordinates, but the vast majority are now correctly positioned on the celestial sphere.

The results of all this are found in the NGC/IC section of this web site. See the Introduction there for details and suggestions on accessing the data.

I am now beginning to collect other data for these objects, types, magnitudes, diameters, redshifts -- whatever information are appropriate for characterizing each object. Until I can get that done, Wolfgang Steinicke, Steve Gottlieb, and Courtney Seligman have collected data for most of the NGC and IC objects. I'm pleased to be able to point you to their NGC/IC pages.

In most cases, the Gaia DR2 positions are the "best" available, agreeing well with positions from earlier astrometric lists (e.g. UCAC, URAT1, 2MASS, SDSS, Pan-STARRS1, etc.), so I have selected the DR2 positions when they are appropriate for the objects. However, in addition to those objects with selected positions more than an arcsecond from the Gaia DR2 positions, some of the stars in the lists have proper motions that have moved them beyond my initial one arcsecond search radius. I have already looked at many of these, and -- like the NGC/IC objects themselves -- will cover the others as I continue to check the lists.

I should mention here that the Gaia team has recently found that DR2 positions have a systematic offset with respect to the ICRS (defined by QSOs) on the order of 30 microarcseconds (see e.g. Lindegren et al., 2018 and Arenou et al., 2018). This is far below the precision which I have adopted (10 milliarcseconds) for display here, so the practical consquences for this list are negligible. It is also possible that galaxy nuclei are measured less accurately than stars because of the surrounding envelope of light from the main body of the galaxy. However, to my knowledge, this remains to be rigorously tested.

I also encourage you to check the positions yourselves as you use the files; I make enough mistakes that I am certain that these files are not bug-free. I recommend CDS's VizieR service for this -- search in catalogue number I/345/gaia2. I also recommend checking the Gaia positions against those in the first Pan-STARRS data release, catalogue number II/349 in VizieR, or any of the other astrometric catalogues included in VizieR.

As usual, I have benefitted from correspondence with Steve Gottlieb, Courtney Seligman, and Steve Waldee on several of the NGC/IC objects. I'm pleased to thank them once again for their help.

Here are some notes from previous releases of these files that are still relevant.

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 which are available here, as are positions and notes for about 200 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, as I mentioned above, 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.

UBVRI Photometry of Galaxies, Globular Clusters, and Stars

In a previous release, I presented the results of my photomtery observing runs at McDonald Observatory. The data consist of large-aperture photometry for 239 nearby galaxies, 18 Galactic globular clusters, more than 550 stars, a few miscellaneous objects, and a new set of secondary standard stars, all in the Johnson/Cousins (UBV)J(RI)C system. McDonald UBVRI photometry, 1982-1988 has the details and the data.

I've had requests to combine the tables of positions and final magnitudes, particularly of the stars. I have done this, and those tables are now available. Again, the directory cited above has the details and the new tables.

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 have been available as printed and bound books, the electronic versions here 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.

    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, but acts as a second link between the northern and southern galaxy surveys.

    All of these catalogues are freely accessible; my coauthors and I ask only for 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
  • Brian Skiff's FTP directory at Lowell Observatory with hundreds of files of useful data
  • Steve Gottlieb's NGC/IC web pages
  • 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
  • Steve Waldee's astronomy web pages
  • The NGC/IC Project
  • The Webb Deep Sky Society
  • Creative Commons
  • Miscellaneous Files

  • Links to Classical 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; 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 even 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 have no such problems with Ralph Vaughan Williams's music; I have loved it unconditionally since I first heard his 5th Symphony in the early 1960s. 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 early 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 just down the road from us, and we are lucky to be living in a city that supports it. 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 commuter 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 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



    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: 16 August 2019