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Digitised Sky Survey

Batch request help

The DSS Batch Request system allows the user to submit up to 15 source positions at once, and obtain GIF, FITS or NDF images of the Digitised Sky Survey fields surrounding those objects. The images may be viewed individually, or downloaded as a single tarfile archive.

The following information must be specified for each object: RA and Dec of field centre (in sexigesimal format, either B1950 or J2000 epoch), image height (in arcsec), image width (in arcsec) and pixel size (in arcsec).

Once all images have been retrieved, a table will be displayed where individual DSS frames can be selected and downloaded.

Restrictions

The following restrictions apply to batch image requests:-
  • The field size must be larger than 17", and smaller than 30 arcmin.

  • A maximum of 15 sources may be submitted in one request.

Service time

The time taken to service a request depends on the size of the requested image, and whether it overlaps the edge of a plate. A typical 15'x15' image close to the centre of a plate will be returned in around 10 seconds or less, whereas a 1x1 degree image could overlap three or four separate plates, and may take a minute or more to be fulfilled. Batch requests for multiple images will be a corresponding multiple of this figure.

If an error message 'document contains no data' is obtained, this may be due to the browser request timing out before the server has returned the data. Try reducing the number or size of images requested. If the problem persists, contact LEDAS Support.

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If you have any problems using this system, please consult the help page or mail LEDAS Support
 
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