I had a note from Brian Skiff in early April 2022 that he could no longer download or even access the data files in the UBVRI section of this web site. The problem manifested itself as a "403 no-permission" error. I found that the error was caused by the file name extension ".dat". Lately, files with this extension have been found on the Web that sometimes harbor spyware and other malicious software that can wreak havoc on networks and individual machines. So, ".dat" files have apparently been "outlawed" by many web service providers, including GoDaddy, the one I use. I suspect that the popular web browsers are also primed to suppress ".dat" files, but have not yet traced the exact source of the error messages.
Consequently, I've had to go through the site and change the extensions on all the ".dat" files to ".txt". This extension appears to work for the time being, allowing you to download the data files without interference or problems. But if you find any other files here that will not download or display properly, please let me know. Thanks!
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.
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.
Stay in touch, and stay safe!
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:
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.
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.
The copies of
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
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.
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.