On 31 May 2005, at 3:09 pm, Pierre Didelon wrote:
> Frederic V. "Rick" Hessman wrote:
>
>> 1. I suggest we rename em from "electromagnetic spectrum" to
>> "emission" and add
>> em.grav-wave (gravitational wave)
>> em.neutrino (neutrino)
> electromagnetic spectrum can concern absorption!
Yes, but if you see anything at all, it's ultimately emission (even if
attenuated).
Admittedly, the better solution is...
>> Alternatively, add
>> phys.grav-wave (gravitational wave)
>> phys.particle (particle emission)
>> phys.particle.cosmic-ray
>> phys.particle.neutrino
> why not electron, proton, neutron....
If people are detecting them, why not? The whole point of em is to
describe by what
means we observe something, and photons are only one of many ways. I'm
sure my
LIGO colleagues would be happy with phys.grav-wave and my HESS/MAGIC
friends
phys.particle.neutrino. The present UCD isn't complete and we
probably won't need
phys.particle.axion for a long while, so the (other) missing entries
aren't a problem, but
right now there are some glaring holes.....
> UCD must define preferentially concept I suppose, isn't it?
> Enumerated lists must be handle with other mechanisms!
> Keyword (<=>UCD) and the corresponding values...Y/N?
I'm not sure what you mean....
>> ...?
>> 2. I suggest we add UCD's for describing calibration observations.
>> Presently, they are
>> few mentions of calibrations at all in the official list:
>> instr.calib (calibration parameter)
>> phot.calib (photometric calibration)
>> and they are sorely needed for things like VOEvent and RTML.
>> It's trivial to say that there's a big different between
>> calibrations (see above) and calibration
>> observations, so new UCD's are needed and it seems the likely
>> candidates would be:
>> obs.calib (calibration observation)
>> obs.calib.dome-flat (dome-flat observation)
>> obs.calib.flux (flux calibration observation)
>> obs.calib.freq (frequency calibration observation)
>> obs.calib.guide-star (guide-star observation, e.g. for
>> intial setup)
>> obs.calib.phot (photometric calibration
>> observation)
>> obs.calib.pos (astrometric calibration observation
>> obs.calib.sky-flat (sky-flat observation)
>> obs.calib.slit-mask (slit-mask calibration observation)
>> obs.calib.spect (spectral type calibration
>> observation)
>> obs.calib.veloc (radial velocity calibration
>> observation, e.g. standard star)
>> obs.calib.wl (wavelength calibration observation)
> Looks like you are trying to define a data model for observation
> and data reduction with UCD... which is perhaps not the best way to go?
Absolutely NOT!!!! I just want to be able to say what something is,
just like the original
VOTable types who wanted to describe their catalogue entries. There's
nothing fundamentally
different in a VO sense between a calibration image (say, an
obs.calib.phot) and a table entry
of the resulting calibration (say, phot.calib). Right now, UCD is
mainly (some but not me might
say only) useful for tables, which is why it needs to be extended to
non-table standard VO uses.
A "data model for observation and data reduction" looks very different
indeed, though it must
ultimately use elements for which the VO has a primitive description.
UCD is our VO dictionary
and data/observation/reduction models are VO prose or poetry: do you
want us to write a VO poem
using words no one (i.e. no app) understands?
>> For completeness, one should then also add
>> phot.calib.flux (photometric flux calibration)
>> phot.calib.mag (photometric magnitude calibration)
>> pos.calib (astrometric calibration)
>> spect.calib (spectroscopic calibration)
>> spect.calib.wl (" " in wavelength)
>> spect.calib.freq (" " in frequency)
>> 3. Suggested addition to spect (Spectroscopy)
>> spect.cont (spectral continuum)
> I like it (personnaly), but why not then spect.background....
If it's needed, why not? Your favorite VO app should be able to know
the
difference between a spectral line and a spectral contiinuum and, in the
real world, between the spectrum in the background (sky). Again, we
have
spect.line right now only because there are spectral line catalogues
out there but
few spectral continuum catalogues.
No, I'm not trying to get a VO ontology through the back door:
ontologies tell us
what the intimate relations between objects are, whereas UCD simply
gives us
the ability to name things. We're still in the VO Neadertaler age
where we've
only agreed that "Ugga" means "rock". I'm worrying about how we
ultimately
want to transmit the knowledge of turning a rock into a spear. I hope
that the problem now isn't going to be getting our colleagues to agree
that we
need a word for "stick"....
Rick
Dr. Frederic V. Hessman Hessman-at-Astro.physik.Uni-Goettingen.DE Universitaets-Sternwarte Tel. +49-551-39-5052 Geismarlandstr. 11 Fax +49-551-39-5043 37083 Goettingen http://www.uni-sw.gwdg.de/~hessman ------------------------------------------------------------------------ -------------------------
http://monet.uni-goettingen.de ------------------------------------------------------------------------ -------------------------Received on 2005-05-31Z15:04:35