Hi, some comments
related to DM ... ;-)
SY, Pierre
Ana Ines Gomez de Castro wrote:
> Hi,
>
> On Fri, 15 Jul 2005, Andrea Preite Martinez wrote:
>
>
>>>3. we propose to add the words "em.wl.start" and "em.wl.stop".
>>>Rationale: they may be useful and flexible characterizations of the
>>>bandpass
>>
>>In many cases I found a data/column description saying: beginning/minimum
>>wl, ending/maximum wl, that I translated using stat.min, stat.max. On the
>>other hand, beginning/ending of observation/exposure deserved wholly new
>>ucd-words! So I'm in favour of introducing these concepts, but as generic
>>qualifiers that can be applied to any axis (time, wl, freq, ..)
>>
>
>
>
> Fine!
>
>
...
>>>8. we propose to change the word code of "instr.filter.transm" and
>>>"instr.spect.resolution" to "V". Rationale: the filter transmission is
>>>an intrinsically vectorial quantity; the spectral resolution as well
>>>(dependence on energy and/or order)
>>
>>The V-flag indicates a vector in <ordinary> space
>>
>
>
> At the very first AVO meeting organized by Piero in Garching there was
> a long discussion about this issue. To fully understand the meaning of
> an image obtained with a given filter you need the Transmittance
> function of the filter ( T(lambda) ). Unless you force all the
> observatories to use exactly the same filters and qualify them,
> specifying the transmittance function is the easiest way to qualify
> them and allow proper comparisons between observations obtained
> with different instruments. Are "functions" allowed as UCDs
>
It is may be more related to DM dealing with characterization
http://alinda.u-strasbg.fr/Model/Characterisation/DM_vers0.1/
to "fully" describe metadata conserning an observation,
including filters and theirs properties...
http://alinda.u-strasbg.fr/Model/Characterisation/DM_vers0.1/3771728084_130.html
UCD is perhaps to general/generic to be complete?
>>
>>>17. "pos.earth", "pos.earth.lat", "pos.earth.lon" should be placed under
>>>the "obs" category. Rationale: these quantity belongs logically to an
>>>observation, not to (the position of) a source
>>
>>I can assure you that pos.earth means position ON the earth, not source
>>position on some earth-based coordinate frame!!
>
>
> Then, why are them within the "pos" category? I thought that "pos" is
> related with "source" and "obs" with the observation/observatory.
> Doesn't it look more natural, obs.pos.earth.lat?
>
but pos.earth.lat or pos.earth.* can perhaps be related to something else
than observation?
>>
>>
>>>An additional point that we have discussed concerns the units in which
>>>interferometric data shall be provided...
>
>
> Matteo and I were dicussing about how interferometric data were
> going to be provided to VO's from the observatories. Interferometric
> data are basically images in the "Fourier space" and not in the
> "physical space". During the AVO experience, Joddrell Bank
> provided directly "physical images" since they carried out
> the Inverse Fourier Tranform before given access to the data
> through the web. So, our question is a generic issue.
>
> Interferometric data are going to become more and more
> common in Astronomy. The "measuring space" of interferometric
> data is the "Fourier- I mean , space frequencies - space".
> Are the interferometric data providers going to release their
> products in the "physical" or in the "Fourier" space?
> Has this issue be discussed?, has been discussed how does
> it affect UCD's?
What UCD did you forsee to be able to describe more precisely interferometry data.
DM group working on characterization would certainly be interested also by this topic.
>
>
> Finally, I've kept thinking about UCD's for "simulations"
> and this is very tricky. As important as the method,
> resolution, time-scales etcc. is to describe the
> boundary and the initial conditions. I still wonder how!!!
>
>
> Cheers,
>
> Ana
>
>
> Prof. Ana I. Gomez de Castro
> Instituto de Astronomia y Geodesia (CSIC-UCM)
> Fac. de CC Matematicas
> Universidad Complutense de Madrid
> 28040 Madrid, Spain
>
> Ph. 34-913944578 (office) 34-659783338 (mobile)
> Email: aig-at-mat.ucm.es
>
>
-- Pierre ------------------------------------------------------------------ DIDELON :@: pdidelon_at_cea.fr Phone : 33 (0)1 69 08 58 89 CEA SACLAY - Service d'Astrophysique 91191 Gif-Sur-Yvette Cedex ------------------------------------------------------------------ Aidez les enfants Tibétains : http://www.a-e-t.org/jcparrain.htm ou d'autres : http://www.sosesf.org/ ------------------------------------------------------------------ La carte n'est pas le territoire - Alfred KORZYBSKI ------------------------------------------------------------------Received on 2005-07-19Z14:10:03