vsa logo
VSA will soon move to

VSA Home
Start Here
Data Overview
Known Issues
the Surveys
Coverage Maps
Schema browser
Data access
Archive Listing
Freeform SQL
SQL Cookbook
Release History
vsa logo bottom
Home | Overview | Browser | Access | Login | Cookbook 
  VSA logo

Region search - help page

This page provides guidance on how to use the region search form. This form allows users quick access to searching a survey by position. Guidelines applicable to all methods of access are given in the data access page.

Users must first select the survey/database/table they wish to search. Each survey has a source table and a detection table. Source tables contain merged records for a given object in the passbands/epochs that define the survey. Detection tables contain full details on the individual passband/epoch measurements.

Users must supply a position (RA/Dec or Galactic) and a search radius in arcminutes. Coordinates can be in sexagesimal or decimal degrees and the system (J2000/B1950/Galactic) must also be specified.

During busy periods large area searches ( radius > 60 arcmin) can take a few minutes writing the results to file so it is recommended that an email address be supplied.

For quick look small area searches it might be possible to view the entire results in the returned HTML table summary. However you want to save the results of searches then specify ASCII, FITS or VOTable (see data access for further details of limits).

The final section of the form is optional and allows more control.

Select - A default set of parameters is returned by the search unless it is overridden by a supplied comma-separated list e.g. to return only the RA and Dec of objects replace default with ra,dec. You can append to the default set by adding extra parameters e.g by entering default,someParameter

Where - The final text box allows you to place constraints on the query e.g. impose a magnitude limit

The schema browser can be used to explore the attributes of a given table.

Home | Overview | Browser | Access | Login | Cookbook
Listing | FreeSQL
Links | Credits

WFAU, Institute for Astronomy,
Royal Observatory, Blackford Hill
Edinburgh, EH9 3HJ, UK