Comparison of VO Spectrum and NED VOTABLE

[Anita Richards]

On Sun, 22 Oct 2006, Jonathan McDowell wrote:

>
> For the record, I reviewed Joe Mazz's VOTABLE format returned by NED.
...
> There are three pieces of data that are mandatory in Spectrum but not
> included in NED: the observation date, observation duration, and
> the aperture size. The lack of these data do limit the scientific
> usefulness of the NED SED VOTABLEs.

What a useful exercise - thanks!  It does highlight the problem with 
having too many mandatory fields, or at least means that we should examine 
what we mean by 'mandatory'.  I suspect taht the reason why these 
(undoubtedly desirable) metadata are missing is because many data 
providers don;t give the information in a convenient way, if at all (e.g. 
it may be squirrelled away in the observing log or instrument 
specification, which might not even be on-line, or in a journal paper).

There will be many VO applications where the missing information is not 
vital, and we don;t want to deprive users of access to NED (or the many 
other archives which will be no better).

Will applications and data searches break if mandatory fields are missing?

Can some tool add automatically the required fields with a value of 'not 
available' or similar?

cheers
Anita

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Dr. Anita M. S. Richards, AstroGrid Astronomer
MERLIN/VLBI National Facility, University of Manchester, 
Jodrell Bank Observatory, Macclesfield, Cheshire SK11 9DL, U.K. 
tel +44 (0)1477 572683 (direct); 571321 (switchboard); 571618 (fax).