On Tue, 18 Jul 2006, Norman Gray wrote:
> Tim,
>
> On 2006 Jul 18 , at 19.03, Tim Jenness wrote:
>
> > 2. Is there any information we can add to the header of the FITS
> > table to enable an application to know that there are pol
> > data in it? (UCD???)
>
> I was just about to say `UCD!', and you beat me to it. The UCD docs
> page is at <http://vizier.u-strasbg.fr/UCD/>, which includes the
> current list, containing several phys.polarization UCDs. The tree
> browser at <http://vizier.u-strasbg.fr/UCD/tree/js/> looks nice, but
> doesn't _actually_ give any more information, documenting
> 'phys.polarization.stokes' as `Stokes polarization'. Also, I think
> it's not the current version! Stick with the text file.
>
> Problem number two is that there is, as far as I'm aware, no blessed
> or unblessed way of associating UCDs with FITS table columns. Mark:
> do you know of any convention? If this is so, then I'm sure it would
Unblessed: the obvious convention is to do this:
TFORM6 = 'D ' / format for column 6
TUNIT6 = 'deg ' / units for column 6
TCOMM6 = 'J2000.0 Right Ascencsion'
TUCD6 = 'pos.eq.ra'
I was about to say that I don't know if anybody does this apart from
STIL. However, looking at my code, it seems that STIL doesn't do it.
I could have sworn I'd put that in ages ago! Well I've just
added for what it's worth, so anyone that uses (future versions of)
STIL for FITS->VOTable conversions will get UCDs transferred using
this mechanism.
Mark
--
Mark Taylor Astronomical Programmer Physics, Bristol University, UK
[log in to unmask] +44-117-928-8776 http://www.star.bris.ac.uk/~mbt/
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