How to consume TAP and SIAP for lightcurve survey ?

Thu Dec 13 23:49:32 PST 2012

Bonjour Petr,

Concerning Aladin questions.

Unfortunately you are right about the lack of query time parameter in VO 
protocols, notably in SIA. But it is quite easy to describe an ad-hoc 
service taking into account the time scale, either as an extension of 
SIA query parameters, or as a totally different service.
If you have a HTTP image cutout service, you can describe the required 
query parameters as a GLU record (see this section in the FAQ: 
http://aladin.u-strasbg.fr/java/FAQ.htx#ToC63 and the example below). 
Aladin will build automatically the corresponding form (in server 
selector) and you will be able to query your image service by time.

Obviously, the result stream must be understand by Aladin. So it can be 
SIA, IDHA (old alternative of SIA), directly a resulting image (FITS, 
JPEG...) or via a VOTable classical catalog with LINK system pointing to 
your images. This last method is very close to your need that you were 
describing by TAP result.
In fact, I think that presently Aladin consumes TAP result as a 
classical source catalog (if there are coordinates) at the difference 
that the URLs in TAP will be just understood as "simple" http links => 
will open your browser instead of loading the result into Aladin. You 
could patch your TAP result by adding in the <FIELD> of your image URLs 
the magic XML tag <LINK content-type="image/fits"/>. In this case, 
Aladin should replace the simple link by button allowing you to load the 
pointed image. See corresponding section in VOTable 1.2 recom (in annexe 
section). I join to my mail a SIA result (I do not have TAP example) 
patched as I described (removed all "VOX: ucd" for forcing Aladin to 
load this VOTable as a classical catalog, and add the LINK element). So 
you just have to load this file in Aladin (see screen dump below).

Another precision, in case of SIA result (not patched), you keep the 
possibility to filter/sort the result tree. Click right on the result 
and select "sort" option. It is clearly less flexible.

About SIAPv2, please point me the recommandation. ;-)

Cheers
Pierre

--

---
Example of GLU record for a SIA service with one additionnal query 
parameter.

%A    MAST
%D    Multimission Archive at STScI (MAST)
%U 
http://archive.stsci.edu/siap/search2.php?FORMAT=image/fits&POS=$1,$2&SIZE=$3,$4&ID=$5
%P.D  1:Right Ascension
%P.D  2:Declination
%P.D  3:Width (deg)
%P.D  4:Height (deg)
%P.D  5:mission/instrument
%P.K  1:Target(RAd)
%P.K  2:Target(DEd)
%P.K  3:Field(RAd)
%P.K  4:Field(DEd)
%P.V  3:0.17
%P.V  4:0.17
%R    Mime(sia/xml)
%Aladin.Menu Archives...
%Aladin.Label Multimission Archive at STScI (MAST)
%Aladin.LabelPlane MAST $4

Le 14/12/2012 03:31, Petr Skoda a écrit :
>
> Hi all,
>
> We are going to prepare a survey of several fields in SMC and LMC 
> which will be observed many times and then to extract the lightcurves 
> from all of the images in a semi-automatic manner. This means identify 
> all stars in an image according to their PSF shape, make astrometry, 
> make an aperture photometry and convert counts to fluxes using 
> identified standard stars and their magnitudes from UCAC4.
>
> The archive will have all available metadata published using TAP 
> Obscore, the info about stars - ie. position in ICRS and flux in 
> physical units will be available through TAP and used to construct the 
> lightcurve relaying on "precise" positions of stars - by preparing SQL 
> query something like - give me all fluxes of stars in circle/rectangle 
> of given small size at given ICRS coordinates in given filter ordered 
> by MJD.
>
> The resulting point of the lightcurve will be somehow wrapped to the 
> form of SDM-like table able to be visualized by e.g. SPLAT or VOPLOT.
>
> But we want also to access the images of given fields and make cutouts 
> of given region using SIAP
>
> With this idea is, however, unclear a lot of issues....
> All you suggestions are welcome!
>
> 1) in SIAP there is only input parameter for location and optional 
> image generation parameters - I cannot select band and mainly the TIME !
> So far all SIAP examples I have found in literature are just showing 
> the selection of given field on sky - but not temporal filter or 
> spectral filter
>
> It is written the SIAP (v1.0)  can provide optional parameters 
> server-dependent.
> I am sure the time and filter (band) is so important that someone had 
> already to solve this problem - can you point me to SIAP service 
> implementing his ?
>
> Another question concerns Aladin - or is there another SIAP enabled 
> viewer ?
>
> How to filter in Aladin query the bands or time ? I have just seen the 
> SIAP are returning tree structure where the band is written but not 
> time - i.e. even if I cant restrict the serarch by query parameters I 
> can at least select right filter from returned results - I would like 
> to do it for time (HJD) as well.
>
> Suppose I will display image in Aladin using SIAP. I want to overlay 
> the identified objects in it which I have written in a table. How to 
> do it ?
> Can I display the content of TAP table ? Or how the catalogue services 
> in Aladin is consumed ? a ConeSearch only ? But how to restrict it to 
> given filter band ? Or time ?
>
> Suppose we would implement the SIAPv2.0 service according the draft. 
> Will there be SIAPv2.0 compatible visual tool ? Will the Aladin 
> support SIAPv2.0 soon ?
>
>
> best regards,
>
> Petr Skoda
>
> *************************************************************************
> *  Petr Skoda                         Phone : +420-323-649201, ext. 361 *
> *  Stellar Department +420-323-620361           *
> *  Astronomical Institute AS CR       Fax   : +420-323-620250           *
> *  251 65 Ondrejov                    e-mail: skoda at sunstel.asu.cas.cz  *
> *  Czech Republic                                                       *
> *************************************************************************

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