Facilities and Instruments Description framework

Abstract accepted by the LISA Scientific Organization Committee:

Title: Shared nomenclature and identifiers for telescopes and instruments

First author: Perret, E. Contributors: Louys M., Buga M., Lesteven S. ...
Institute: Centre de données astronomiques de Strasbourg , CNRS- Unistra UMR 7550

Absctract:
In the context of sharing public data, science results are expected to be reproducible and therefore we need full traceability of the origin of the data. On the documentalist side, there is a need to relate instrumental origins to published data. We propose to define a shared nomenclature to index each publication with unique designations for facilities, telescopes and instruments based on the Virtual Observatory work on semantics.
This would help the documentalists to check the consistency of the instrumental description in publications or make it more explicit. Observation period, data quality and spectral coverage for instance, may be checked by referencing to a global instrumentation service which gathers the nominal observation parameters for the telescope/facility/instrument involved.
Based on this indexation mechanism, then the bibliographic metrics for telescope/instrument usage would be easy to compute, and tracking services like the ESO telescope bibliography database (TelBib) or others would be easier to feed.
This paper traces the existing initiatives and propose a facility description framework reusing Virtual Observatory metadata which could be fed by the community.

Describing Facilities, Telescopes and Instruments

This is a common effort initiated in the Semantics working group, namely with suggestions from Planetary science services at Paris Obseervatory and collaborators.

The idea is to identify and gather needs for a homogeneized description and identification of instruments, telescopes, space missions, space crafts, etc. and create a maintained repository of identifiers re-usable by the community for

• keywords verifications in data sets serialisation
• data citation
• facilicity citations tracing
• etc.

As stated during the CDS HCERES evaluation, "science questions drive the need for multi-lambda, multi-messenger observations" (Mark Allen, HCERES).

For a precise and efficient tracking of the origin of metadata, we need to track details on instruments and facilities used for the data acquisition especilly because it uses nowadays, various regimes and modes to combine observations for a scientific purpose.

Existing Initiatives

This page records some of the existing initiatives on the topic

UseCases

Use Cases for Facilities description

Discussion for a description schema

from the usage exposed , we see the facilities and instruments need to be standardized (name , ids ) together with physical features such as spectral range, operational period, field of view, spatial resolution, mode, etc.

Nominal feature values for instruments can be used in various services, when the information attached to a dataset ( associated data , catalog , etc) is not available).

Use cases exposed above may have 3 levels of usage for instruments/ telecope parameters:

• precise : theses are the exact parameters for a specific observation
• intermediate: the usual values ex spectral coverage , recorded for a data collection ( ex 2MASS J --> fits the range of filter J.
  This applies when fluxes have been converted to a different photometric system than the original instrumental one
• global : when no other info is provided for the spectral range of a data set, the min and max spectral range of the instrument can be used.

Example of Usage : Missions/ Telescopes X Time line ( Mihaela Buga , CDS)

                                                                
        -----------------------------------------------------------------------------------------------> 
        1978 1981 1883  1986 1990  1993  1995 1996    1999  2001  2002   2004                        2011
        Einstein   EXOSAT     |      |            Beppo SAX('96-'02) |     SWIFT (2004-ongoing?)       
                             BBXRT   |                               INTEGRAL(2002-ongoing)               
                              |      |-----------------------|
                              |             ASCA(1993-2001)          
                              |            |----------------------------------------------------------|
                              |                                RXTE(1995-2011)    
                              |-----------------------|
                                  Rosat (1990-1999)   |
                                                      Chandra(1999-ongoing)
                                                      XMM-Netwon : EPIC, MOS/PM, RGS (1999-ongoing)                     

Filter names spread along the wavelentgh axis ( Mihaela Buga , CDS)

                                                      
             3000A    4000A    5000A    6000A    7000A    8000A    9000A    10000A
             300nm    400nm    500nm    600nm    700nm    800nm    900nm    1µm     1.2µm      1.6µm     2.1µm                                         
             ---------------------------------------------------------------------------------------------------------> 
                 U u      g B        V       r R       i I          z                J          H         K         filtres Simbad
                          B=F435W    V=F555W r=F625W   i=F775W      z=F850LP         J=F110W    H=F160W             filtres HST
                          g=F475W                      I=F814W                                                      filtres HST
           ___________________________                                   ____________________________________                                              
                                      |                                 |
                                      |                                 |
             0.01nm    10nm      380nm(3800A)    700nm(7000A)   1µm   2.5µm  30µm  300µm  1mm/300GHz   1cm/30GHz    1m/ 300MHz       longueur d'onde                                               
        --------|--------|----------|----------------------------|-------|-----|-----|---------|-----------|---------|----------------> 
         Gam         X        UV             Opt                    NIR    MIR   FIR     smm        mm      micro-onde                                            
                                                                                                            -------------Rad----> 

It shows that by having a centralised description of telescopes/instruments and the physical features of spectral range or operationnal periods, the discoverability of specific observations is facilitated.

First attempt in the IVOA Framework ( 2015)

At the ADASS conference in 2015 , we presented a first Model to describe Facilities, Telescopes, space missions , instruments , by gathering properties and reusing the VOREsource schema defined in the IVOA .

see the poster attached for a simple overview http://wiki.ivoa.net/internal/IVOA/UniFacil/ADASS2015-VOFacilities-posterv6.pdf

This effort deals with the definition of a core set of metadata to represent basic information for instruments, telescopes , space missions and facilities in general in

astronomy.

The basic elements are described in an XML schema document vailable here: XML schema For a Facility Model

The graphical representation for each element of this small model is also available as png images :

• VOresource
• VOFacility
• Space Mission
• Space craft
• Telescope

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