About the draft itself Re: WD-SIA-2.0

[Patrick Dowler]

On 14/04/14 01:00 PM, Arnold Rots wrote:
> And what is "barycentric wavelength"? Conversion from frequency to
> wavelength as applied at the gravitational potential at the barycenter?
> Or does it mean to reduce the spectral coordinate to the barycenter only
> dynamically? That's pretty inconvenient for people who are doing
> Galactic work.

The intent here is that the BAND parameter only supports one unit (m) 
and one reference position/time/scale/hard-to-remember thing.

Since we have to pick one, can you tell me the one most suitable that 
would apply to BAND and TIME parameters. Note that the draft currently 
just refers to the same restricted time metadata as DALI uses for 
literal values (time scale UTC and unknown reference position). What 
should we use for wavelength values in the BAND parameter, knowing that 
implementers will actually just query the wavelength(s) they have in 
files, filter lookup tables, or spectral wcs already.

PS-Yes, wavelength in meters - no one's first choice :-)

-- 

Patrick Dowler
Canadian Astronomy Data Centre
National Research Council Canada
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