UsecaseUnifacil < IVOA

IVOA Web>IvoaSemantics>UniFacil>UsecaseUnifacil (2017-02-22, MireilleLouys) (raw view)
---++ 
---+ Facilities and Instruments Description framework
---++ <strong>Use-cases <br /></strong>

*CDS usages for SIMBAD - (documentalist: Mihaela Buga):*

In order to add wavelenghts and quality of the coordinates of the astronomical objects that we record in SIMBAD we need to know with which instruments the astronomical objects of a publication are observed and from where the coordinates given in the paper are taken. An astronomer can give the approximate resolution of an instrument (that we traduce in SIMBAD by a quality letter: A=nice quality, E=very poor quality, etc.) and we can also indicate in which domain-range the position is given (Optical, Gamma, NIR, smm, FIR, Radio)...

In order to keep a track of the questions ask to astronomers and of telescopes/instruments found in the litterature, an internal list has been created on a TWiki.

Currently, it lists ~75 telescopes/missions: http://cds.u-strasbg.fr/twiki/bin/view/Ressources/CoordLambdaQualite1#ListMis

We have telescopes, instruments, wavelength domains, URLs toward the telescope site and Wikipedia and notes from astronomers concerning the quality of astrometry.

*CDS usages for VizieR - (documentalist: Emmanuelle Perret, Sylvain Guéhenneux, Patricia Vannier et Marianne Brouty)*:

1. Describe Vizier table content

Description of measurements from tables in publications implies a section "Description" in a ReadMe file describing the observations: telescope/instrument and its location, date of observations are mandatory. If possible, wavelength range and resolution are also given (useful for SIMBAD).

2. Plotting SED

Photometry from tables is used for the service called "Photometry viewer", it converts magnitudes in fluxes when possible and gather all the fluxes around a position to trace the spectral energy distribution (SED) of an object (if the search around the position only gives one object)...

See also recent presentation by Gilles Landais at Trieste Interop 2016:<br>
http://cds.u-strasbg.fr/~landais/presentations/IVOA_2016Trieste_Photometry_VizieR.pdf

In order to do so, we attribute filters to the measurements which are gathered in an internal table:<br>
http://vizier.u-strasbg.fr/viz-bin/VizieR-2?-source=METAfilter

System of photometry is important and in that case, we go up to the precise filter with effective wavelength and width of the filter.<br>
All the filters from the SVO (http://svo2.cab.inta-csic.es/theory/fps/) have been included in this table.

3. Attach data files to catalogs in Vizier (Gilles Landais, Laurent Michel, Patricia Vannier)

At submission or after, associated data published and reviewed together with a publication can be proposed by authors. <br>
These data can be stored at CDS data center in the dedicated SAADA VO data base and linked to submitted catalogs.<br>
A VO metadata description (Obscore) is mapped from the submitted FITS files.

Authors and documentalists are assisted in the mapping process by extracting keywords from FITS headers (TEL_ID, DATE... ?)

Telecope and instrument names need to be standardized together with their nominal features, namely spectral range (min, max). This information can fill the gap , when no precise coverage is given for the specific associated data.<br> 
All parameters describing telescope / instrument coverage could be taken from a formalized dictionnary (see the dictionnary in Saada - created by Laurent Michel).

Purpose: database (http://cdsarc.u-strasbg.fr/assocdata/) searchable by observation date, spectral bands, coordinates in time series, spectra, images associated to publications.

See also the presentation by Gilles Landais at PREDON in november 2016 :<br>
http://cds.u-strasbg.fr/~landais/presentations/PREDON2016_curationVizieR.pdf

*CDS usages for the Dictionary of Nomenclature - (documentalist: Marianne Brouty & Fabienne Woelfel)*:

When the publication is linked to specific observations, the facility is described along with the acronym created for the paper.<br> 
For instance, see section Note for http://cds.u-strasbg.fr/cgi-bin/Dic-Simbad?/3104709

*CDS usages for the HiPS in Aladin - (documentalist: Mihaela Buga )*:

Diverse metadata are used to index the HiPS (Hierarchical Progressive Surveys) in Aladin. <br> In properties of HiPS, "obs_description" contain the telescope name and can contain the instrument in some cases. <br>
As this is not always filled or mentionned in this free text section , dedicated keywords , taken from Obscore metadata could be used : facility_name , instrument_name, or compatible ids . 

All properties of HiPS: http://alasky.unistra.fr/MocServer/query?hips_service_url=*&dataproduct_type=!catalog&dataproduct_type=!cube&get=record

Currently we use a simple acronym, but a unique id would be better (pid=persistent ID) because it will link to the VO registry with a basic description and the URL toward the instrument archives from the agencies.

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Topic revision: r1 - 2017-02-22 - MireilleLouys
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