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

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.

I believe that the observations of the galaxies are now useful only for calibration of individual CCD (or other digital) images of the objects, but others may find uses for them in projects that I don't currently envision. The observations of stars and globular clusters, however, may be of more interest.

Finally, I've recently published a paper in The Observatory (142, 207, 2022) summarizing these McDonald observations. Currently, the observations themselves are available on this Web site, and can also be retrieved from CDS/VizieR, though in a slightly different form.


This release of the NGC/IC position data is of particular interest as I have taken the time to match the lists to the Gaia Early Data Release 3 (EDR3). Over 80% of the objects in the NGC/IC files now have very accurate positions taken from EDR3. While I will check future Gaia releases (DR4 is projected for release in 2023), EDR3 will probably be the last major list of positions that I incorporate in these files. The position errors in EDR3 are generally better than a milliarcsecond (for stellar images including most galaxy nuclei) -- for the purposes of this list, that is quite accurate enough. I will, of course, be watching for errors, and will certainly correct and update positions that are wrong. As always, I encourage you to let me know of any bugs that you find. I'll be happy to correct them.

I have also updated the files with only NGC and IC objects included. If your primary interest is the identification of the deep sky objects discovered in the 18th, 19th, and early 20th centuries, you will want to turn to these files first. Eventually, I'll add the photometric and spectroscopic data for each object: diameter, position angle, magnitudes and/or colors, redshift, and more. See the GGCl, RC3, and SGC/SEGC sections below for ideas on where I might take data entries for the NGC and IC objects.

Here are some additional introductory remarks unchanged from previous releases. Skip them if you've already seen them.

A Galactic Globular Cluster list (GGCl), 2nd version

It might seem a bit off-topic for a nominally extragalactic astronomer to be dabbling with Galactic globulars. In fact, I've been interested in them for some time, and have published at least one paper with UBV aperture photometry for seven Galactic globulars (AJ 82, 193, 1977). I've also observed 18 globulars in the course of my UBVRI work on galaxies.

An obvious connection between globulars and galaxies is their extent on the sky. This means that they can be treated in much the same way to find their isophotal diameters and magnitudes as well as their total magnitudes and colors. Working towards a list of Galactic globulars with these photometric parameters determined as well as possible has been the major goal of my present work on the globulars. The result is the Galactic Globular Cluster list (now in its second version including position angles when known) aimed directly at visual observers.

This has 159 entries at the moment, almost all with data in the V band. There are at least a couple of dozen candidate globulars now being studied, and even more candidate globulars are being discovered as I write this. I'll try to keep this list more or less up to date as V-band data become available for the included clusters as well as the candidates. Many of these "new" globulars, though, are hidden behind the Milky Way's dust and rich star fields, so may never be seen visually. So, these clusters, visible only in infrared bands, are not good candidates for this list, though a few have snuck in already.

As always, I'll be happy to receive bug reports, and to fix typos, blunders, and general sloppiness.


During my work on collecting data for the NGC/IC objects, and in pulling together a catalogue of galaxies with just the data essential for amateur astronomers, I adopted the photometric systems we developed thirty years ago for the Third Reference Catalogue of Bright Galaxies. While those systems remain useful and -- within their statistical errors -- accurate, RC3 itself remained moderately difficult to access for two reasons: 1) 6000 or so of its galaxies had positions with precisions of only six seconds of time and one arcminute; and 2) searching for a specific name was more difficult than it should have been due to the unusual formatting of the names.

I have addressed both of these issues with a new version of RC3 which I have called "RC3.10.0". Follow that link for the details, along with notes about the many other additions and changes that I've made in the catalogue. Several things are worth noting here:

  1. All of the galaxies listed in RC3 now have positions with precisions of 0.1 seconds of time and 1 arcsecond. The positional accuracy is on the order of ±2 arcseconds for all galaxies with updated positions, and ±5-7 arcseconds for others, particularly in the southern sky.
  2. The format of the catalogue is unchanged, so if you have an RC3 reader, it should still work.
  3. There are no additional galaxies, but ...
  4. ... several plate defects and four Galactic objects (two planetary nebulae, a diffuse nebula, and a star) have been removed. There are now 23,001 galaxies listed in RC3.10.


Previously in this space, I mentioned that I had finally, after 40-odd years, pretty much completed my work on the identification and positions of the NGC and IC objects. All that can be found in the NGC/IC section of this web site. That has details and suggestions for accessing the data. (Also see the first paragraph of this web page for an introduction to the latest information that I've collected for the NGC and IC objects.)

Now that the basic NGC/IC identification phase is pretty well done, I have turned my attention to collecting other data for these objects. I have started with galaxies as those are not only the most numerous deep sky objects, but they are the objects which I have specifically catalogued and studied during my career as a professional astronomer.

So, I have reassessed the two basic galaxy catalogues that I have had a hand in: The Southern Galaxy Catalogue (SGC) with Gerard and Antoinette de Vaucouleurs, and The South-Equatorial Galaxy Catalogue (SEGC) with Brian Skiff. Most of this work has involved collecting and transforming published magnitudes and colors to the general V and B-V systems of the Third Reference Catalogue of Bright Galaxies (RC3).

Along the way, I have reduced the diameters in both southern catalogues to the RC3 system; have "uncoded" the coded types given in SGC; added position angles to the SGC entries; and collected V-band magnitudes, B-V color indices, and redshifts for almost all the galaxies in both catalogues. I have also simplified the format into a single line for each galaxy, hopefully making the lists easier to read or to import into databases. There is more to be done with that particular aspect of the data presentation, but that will see light in a later release. In the meantime, all the data are available through the links above, and are ready to use.

The updates to these two catalogues give basic data for about 8500 southern galaxies, and -- further -- ways to reduce similar data for tens of thousands of other fainter and smaller southern galaxies. The next obvious steps are 1) to merge the southern data into the NGC/IC lists, and 2) to begin work on the northern equivalent of these southern files. This will eventually result in a complete presentation of visual data for all of the old catalogue entries.

In the meantime, 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 for other views of the objects.

As usual, I have benefitted from correspondence with Steve and Courtney, as well as Yann Pothier, Steve Waldee, Brian Skiff, and Sue French, on several of the NGC/IC objects. I'm pleased to thank them once again for their help.

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 (and for RC3 and SGC, updated) 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.

    I have also made available in this release an updated version 2.0 of SGC with more accurate, more precise J2000 positions; full galaxy types; diameters reduced to the systems of RC3; V magnitudes and B-V colors, also on the RC3 systems; and redshifts. Details are in the Southern Galaxy Catalogue pages.

    Similarly, as noted above, an updated version of RC3 is now available in the RC3 section of this web site.

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

    Also, as noted above, an enhanced version (2.0) of

  • A South-Equatorial Galaxy Catalogue by Harold G. Corwin, Jr. and Brian A. Skiff
  • is now available. This, like the previous versions, 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. In addition, version 2.0 has J2000.0 positions, the diameters reduced to the RC3 system; V magnitudes and B-V colors, also on the RC3 systems; and redshifts.

    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
  • 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
  • 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. (Coincidentally, the 5th Symphony was first performed the year I was born; it is just my age.) 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 small 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 more than 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. And "Ralph", as is also common in the UK, is pronounced "Rafe".
  • The Buffalo Philharmonic Orchestra is our orchestra. It 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 on the Naxos and Beau Fleuve labels, 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 (RPA) (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 just announced its new site. 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, which is a region unto itself!
  • 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 HO 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 -- on which we enjoyed several trips during our time in California.

  • 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, and while what I do need from them has become more difficult to use over the years -- and occasionally frustrating -- I stick with them out of inertia.

    Latest update: 2 April 2024