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Tutorial: Proximity Search using the DAS Imaging Query Server

Given a list of objects (or coordinates), the following procedure outlines how to find the closest object in the SDSS database to these coordinates. The Imaging Query Server (IQS) is used to conduct the search.
  1. Access the Imaging Query Server interface.
  2. Select the Imaging parameters that you want returned.
  3. Select Target Imaging and/or Best Imaging.
  4. Click the "Proximity Search" button.
  5. Enter the ra, dec and search radius in the "List of" box. The first line must contain the text "ra, dec, sep" (NB not "radius"). The order is not important, but must be specified. Units for "separation" are arcseconds, maximum of 10. You may also use a local file by specifying it in the upload box.
  6. Select imaging constraints.
  7. Submit.


  1. Only one (1) object will be returned per entry.
  2. Maximum search radius is 10 arc-sec around the submitted coordinates.
  3. For more than one returned object, you want to use the "Cone Search"
  4. A return of all zeros (0) indicates no object was found within the search radius, or the search area is not in the DR1 area.
  5. A MAXIMUM list of 100 is accepted per submission to avoid clogging the database server.

Time Estimate for Query Response

1-2 seconds per object submitted.


Cut and paste these coordinates:

ra, dec, sep
159.90897, -0.08782, 10
195.0, 63.0, 10
190.0, 55.0, 10
0,90, 0

Since SDSS hasn't observed the north pole region, only three matches are returned.

Last modified: Sun Mar 14 23:01:16 CST 2004