[obs-tap]observable quantities in observations and their UCDs
Anita M. S. Richards
a.m.s.richards at manchester.ac.uk
Wed Jun 23 10:13:44 PDT 2010
> As I already mentioned in our discussion here at CDS, I do not think that
> "velocity" is observable in any sense. I would agree that it can be a
> spectral coordinate, but we NEVER directly observe velocities. Velocities are
> results of the [model-dependent] data analysis.
> With best regards,
Hm, but what about proper motions?
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