Re: New UCD list

Arnold Rots wrote:
>
> You may want to look the gory detail up in the STC document.
> I'd much rather tie "radial velocities" to redshift and, yes, they are
> basically just formalisms, not physical velocities; but your
> description is not entirely accurate.

  Hi,

  I had looked at the FITS spectral coordinates paper, as this is what Jonathan originally referenced to in his suggestion.   See http://pan-starrs.ifa.hawaii.edu/
project/IPP/wcs_paper3_20050126.pdf

  I read there that there are 4 different quantities:

1. apparent radial velocity
2. "radio" velocity
3. "optical" velocity
4. redshift

  My last mail was just to suggest that we could have 2 ucd words for quantities 2 and 3 (I suggest spect.radioVeloc and spect.opticalVeloc), instead of the single spect.veloc existing now, which is not accurate enough
for some people.   

  I don't pretend we can/need be as accurate as STC with a few UCD words - leave
this to specific stc:utypes. At least we must try to describe the basic existing quantities with UCD.

Sebastien.

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