release of a new version for the WD Observation Core Components data model and ObsTAP

Patrick Dowler patrick.dowler at nrc-cnrc.gc.ca
Wed Mar 9 09:37:16 PST 2011


Just responses to two of these points:

On 2011-03-09 01:27:57 Anita M. S. Richards wrote:
> p14 Table 1 and elsewhere
> 
> What about Solar System or other data which cannot be described at all by
> RA and Dec (because the body moves too fast, for example?) For example,
> many ALMA observation sets will contain a moon as amplitude calibrator
> along with extragalactic sources.  It would be nice to have an option e.g.
> 'coosys other' if not all the options.  Alternatively, one could allow RA
> and Dec to be nil and identify Solar System objects by name and time-date.

The s_region column allows ANY STC region; the service has to be able to 
accept ADQL queries that use that column. It is always the caes that services 
are responsible for converting spatial queries to the system they use. 

s_ra and s_dec are allowed to be NULL in the database, even if s_region is not 
null.

The s_ra is and s_dec columns are there as a convenience only; they are not 
actually required for any of the use cases and, if the s_region was in ICRS 
the values could be trivially obtained in ADQL with coord1(centroid(s_region)) 
and coord2(centroid(s_region)), although one might also want to select 
coordsys(s_region) as well, or - even better - coordsys(centroid(region)) just 
in case other transformations are going on and they really want to be careful.


> p15 3.3.1 Data Product Type
> Is it worth stating explicitly that visibility data is likely to be in
> formats such as FITS, Measurement Sets (MS) or Science Data Models (SDM,
> ASDM etc.) (usually distributed as tar or zip directories) - just so that
> implementors can recognise the type of the latter, relatively new formats?

The access_format will say if it is FITS (application/fits is a valid value of 
that column).

-- 

Patrick Dowler
Tel/Tél: (250) 363-0044
Canadian Astronomy Data Centre
National Research Council Canada
5071 West Saanich Road
Victoria, BC V9E 2M7

Centre canadien de donnees astronomiques
Conseil national de recherches Canada
5071, chemin West Saanich
Victoria (C.-B.) V9E 2M7


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