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How to extract sources from an image and crossmatch with standard catalogs

  • First you will need a FITS image with WCS astrometry (1). For this example, I took a SDSS image that can be downloaded here.

  • Point your browser to http://nvogre.astro.washington.edu:8080/wesix

  • Use the Browse button (1) to locate your image.

  • Choose which catalog you will crossmatch your image with (2). Wesix first extracts the sources, then compares for matches with one of the standard catalogs. I chose USNO-B.

  • Click "Submit".

  • You will be asked which fields you would like to see, first the Sextractor fields that are computed from your image (3), and also the fields from your chosen crossmatch catalog (4), in this case USNO-B.

  • When the crossmatch table has been made, you can view your image with sources (5), or make scatter plots (6), or view the table (7).

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Supported by the National Science Foundation
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