Using Multi Query function
Perhaps the most exciting and useful addition from V1.2.3.1 is the inclusion of a Multi Query capability which allows you to define and execute a search against any catalogue resource for a user supplied list of positions on the sky. In the screenshot below, the user has selected the USNO-B all sky optical catalogue resource in VOExplorer:
Under the Action pane the user can select the usual Query option to launch Astroscope and search for a given position. However, a new option Multi Query is now available which allows the user to launch an interface to search the catalogue for a list of positions on the sky as shown below:
Note the service to be searched under IVOA-ID. Click the magnifying glass button to choose an alternative service if desired. Once the catalogue service is chosen the user must upload their list of object positions by clicking the Table URL button under the Position pane and the following dialogue is opened on the desktop.
Here the user can select the table from a either their local disk, VOSpace, sftp location or other URL. To perform the multi position search itself will require a login to VOSpace (you must register with AstroGrid to enable this if you haven't done so already). The table can be in any of the following formats: VOTable, CSV, ASCII, FITS, TST, IPAC, WDS and identified using the Format pull-down menu. Specify the RA and Dec Columns within the uploaded table using either the column number as shown or choose the actual column name. A wizard button will attempt to identify the relevant columns in the table if preferred. Next a search radius for each object position is required. Finally, choose which output format: all matches in the catalogue within the search radius or the best match (nearest on sky). In the example shown below the user has chosen to upload a subset from the 2MASS point source catalogue which match criteria for a given science problem and choose to output the best match within 0.01 degrees in the USNO-B catalogue for each object in the list.
Click the Start Search button to launch the query. The status of your launched job is shown top right as shown below. Once the job has completed a range of actions are available on the output Results.vot table. In addition to view and download options, if TopCat or other SAMP enabled VO tools are running the results can be passed directly for viewing, overlay and further analysis.
See the STILTS coneskymatch documentation for more detailed information on the underlying STILTS library and algorithms underpinning this Multi Query functionality.
