Hey all

I was trying to identify some recently observed galaxies using NED. One of the “anonymous” galaxies I had picked up was the small Im galaxy between NGC2633 and NGC2634 in Camelopardalis. NED provided the ID as: 2MASXJ08482381+7402176. Ahh, just rolls off the tongue, doesn’t it??? At any rate, it got me to thinking about the recent propensity to catalogue galaxies by their celestial coordinates. 2MASS, SDSS and GALEX all do this but interestingly there are ALWAYS slight differences in the coordinates (of course, always with the last couple of digits in the RA and DEC coordinates, a byproduct of each catalogue defining the centre of a galaxy slightly differently). For instance, here are the IDs for IC4554:

2MASX J15350481+2328457
SDSS J153504.83+232845.4
GALEXASC J153504.88+232844.3

I'm wondering: does anyone know if there is any interest in the professional community to standardize the coordinates so that they would be identical no matter which survey catalogue was used? I know this involves literally millions of galaxies,but.... Also, these coordinates are all for epoch 2000.0. What happens in 2050 (and beyond) as precession slowly causes changes in the coordinates for each object (and big changes for objects near the celestial poles)? The CGCG used epoch 1950 as its standard, but this catalogue doesn’t seem to be used much anymore. Wouldn’t it have been wiser for the professionals to use a coordinate system using the Milky Way as the reference? We could at least go a 100,000 years or so before we would start seeing significant drift in coordinates. And by then, I mean, really, who amongst us would really care?

Anyone out there willing to straighten me out on this?