On Jul 15, 2005, at 4:54 AM, Andrea Preite Martinez wrote:
> I whould say seeing is a property of a <site>.
> I also agree with Rick's suggestion, it's a property of the
> <weather> at a
> given site.
For any given tabular example, the concept of "seeing" likely includes effects local to the dome and telescope, which often dominate the resulting measured PSF, independent of the theoretical diffraction limit of the telescope. Rarely will seeing strictly derived from the weather be measured or recorded.
> A good occasion to repeat that the list of words was initially built
> entirely bottom-up, i.e. from data description. If "instr.precision"
> exists, it means that the description "precision", although too
> generic,
> has been used by some author.
This is a good way to build such a list. It is not the only way one might proceed. If namespaces (or the potential for same) are not introduced early in the process, there will be much more trouble later when the VO inevitably finds some way to squeeze them in.
> I need a use-case to make-up my mind
A single use-case is not much point. The idea is to assemble a range of use-cases such that all the potential behaviors of the system or model are elucidated.
> ?? UCDs do not care about units..
Indeed, but sometimes a preference is implicit. Seeing is likely in arcseconds, dates are likely ISO 8601, and so forth.
Rob Seaman
NOAO
Received on 2005-07-15Z17:42:38