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Data Access

Data access to the catalogues and images has been provided by the Astrogrid project. There are two separate interfaces to the IDR. Users who only want to extract a small part of the PhotoObjBest catalogue around a position will find the web interface useful. Users who want more sophisticated quieries on e.g. colours will find the Astrogrid Query Builder inside VO Desktop more suited to their needs.

Catalogue Access

NOTE: All magnitudes are given in the Vega system.


Using the web interface to the release you can perform cone searches of the IDR catalogue (only the PhotoObjBest). This is built using Flash so you will need a browser with the Adobe Flash Player plugin installed.

Astrogrid Portal


AG Portal ToolbarUsing the toolbar at the top of the page  you can switch between the Cone Search, Image Search and Postage Stamps interfaces. The Cone Search is selected by default.


Select the catalogue to query (apart from IPHAS you can choose between 2MASS, SDSS, CMC14 - Carslberg Meridian Circle Astrometric and Photometric Catalogue - or NED) and either insert an object name or some coordinates. Select also a search radius and its units. The maximum radius allowed is 1 degrees.

Select also an output format. VOTable is the standard table for the VO (it is like an HTML table) and you can convert it to any format including FITS using e.g. STILTS. There is an option to load the table directly into TOPCAT. In that case if you do not have TOPCAT installed it would be automatically downloaded and launched and the table will be loaded.

Catalogue cross match

The list upload button allows the upload of an object list in FITS, VOTable or CSV to cross match with the selected service. Note that only the first 1000 rows of the list will be crossmatched. The lists need to have the R.A. and Dec columns in decimal degrees and named ra and dec.

Image Access

The  Image Search shares the same interface and options of the Cone Search. The only difference is that resultant table is a list of images which satisfy the search criteria (i.e. images which are included in the specified box). There is one row per image and each row contains a url link to download the image. Tools like TOPCAT and Aladin can load this table and download and display the images automatically. If you save the output table to disk you can also use the python script in order to save the images to local disk as:

> python table.vot saved saved saved saved saved


You can view postage stamps of your sources selecting the Postage Stamps interface in the toolbar. The boxes to fill in are self-explanatory again: image server, object name, coordinates and size of the postage in arcsec. You can also tick different options in order to e.g. draw a cross in the center of the postage. Then click on submit and wait for the images to be created and downloaded. You can browse them using a coverflow-like interface.



Data Quality Control Table

An alternative way of accessing individual images and catalogues is from the INT WFS data quality query available from here.

Full Access Using VO Desktop

Using the Astrogrid VO Desktop it is possible to access the full range catalogues included in the IDR as well as perform complex queries using the ADQL language. ADQL stands for Astronomical Dataset Query Language and it is a subset of SQL with added astronomical capabilities. A tutorial on using the VO Desktop to perform a query to the IDR database is available from the Astrogrid  IPHAS tutorial. Note that Astrogrid is releasing a beta of its new interface very soon - we will post here a new tutorial when this is available.