There is a relatively new software program called Desktop Universe
(http://www.desktopuniverse.com/ ). After the earlier discussion on
database accuracy, I sent them an e-m to find out what they did with
their db. Below is their response. I don't know how to interpret it, and
I'd be interested in comments from those who do.
Thanks,
--Gib
[From Desktop Universe tech]
In a nutshell, here's how we constructed our databases:
1) For galaxies, we simply accepted the PGC2002 data, wherein supposedly
numerous errors from earlier editions of the PGC have been corrected.
But we have found a few errors ourselves.
2) For planetary nebulae, we used the ESO-Strasbourg catalog, having to
make only a few small fixes.
2) For all other DSO classes, we constructed dedicated catalogs from a
number of sources. So we have ONLY ONE catalog for each object type.
This allowed us to keep to a consistent format for the presentation of
data applicable to each.
3) In addition to using some of Harold Corwin's corrected NGC/IC
positions, we used the Digitized Sky Survey and our own imagery to
refine the positions and sizes for MANY hundreds of open clusters and
nebulae (emission, reflection and dark). Of course, for nebulae with
indistinct edges or complex shapes, ten investigators will get ten
different results. So in this area we can't say we have the last word!
So you can see that except for galaxies (the PGC2002 containing nearly
1 million entries!), and for the most part planetaries, we didn't simply
incorporate existing catalogs. We effectively "created" our own from
diverse sources. The source data are outlined on our web site. The
Software page on the site has a link to an HTML document called "Deep
Sky Data Summary."
I suppose you've compared the illustration straddling pp. 120-121 in
the March S&T with the display as rendered by DTU for yourself? You'll
notice that in DTU NGC2637 is also identified in the info box as CGCG
89-65.
Glenn