Tim,
> This is impressive. Will there be a mapping from/to the specview style?
"specview style" ??? Don't follow...
> > - flux per unit wavelength
> > - flux per unit frequency
> >
> > but will recognised and use any appropriate units for describing these
> > systems (W/m**2/Hz, Jy, mJy, etc). Requests for support for other systems
> > will be considered...
>
> Jy/arcsec**2 [ie flux per unit area]
>
> Units of per unit area implies that aperture photometry returned from
> photom/aperadd should take the multiplier into account when reporting the
> answer...
So this would presumable require a FluxFrame to have a "BeamSize"
attribute? Would have to decide on units...
> all our spectral line data are in corrected antenna temperature...
Can you point me at a descrtiption of how to convert between antenna
temperature and flux density?
> How does this class interact with NDF flux units? Does KAPPA act like it
> does when reading coordinate information and automatically create .WCS
> component which includes a FluxFrame if units are specified in the NDF?
The logical thing to do would be to have a new component in the NDF
structure which would be like the WCS component in that it would just be
a placeholder for an AST FrameSet, but the FrameSet would describe
relationships between different systems for representing pixel value
rather than pixel position. This is the model I tried hard to persuade the
IVOA DM group about, but failed to get past Brian Thomas. However,
modifying the NDF library would be a serious amount of work.
> Does/should the kappa setunits command forward the request onto AST?
Yes, SETUNITS should be modified to look out for recognisable flux units.
I've not done this yet.
David
|