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The STScI Digitized Sky Survey

Phase 2 User's Guide

Use this version of the Digitized Sky Survey form to extract an image for the appropriate survey for determining positions for Phase 2 of HST proposal submission. Extractions will be from the Quick V survey for northern declinations, and from the 1st generation scans for southern declinations. This will ensure that your submitted positions are in the HST Guide Stars frame.

Images will be in FITS format. Your browser should attempt to save the file to disk instead of trying to display it.

Enter the coordinates (equatorial right ascension and declination) on which you would like the scan to be centered, and select either J2000 or B1950 for the equinox of the coordinates.

The coordinates can be in either decimal degrees or HMS/DMS format. (That's decimal degrees for the RA, not decimal hours.) If you use HMS/DMS format, the hours/degrees, minutes, and seconds should be separated by a space, and seconds must be included.

For example:

        RA               DEC
     ------------     -------------
     187.277915           2.052389
     12 22 31.98       29 53 45.55
If the dec is positive, then the plus sign is optional.

Image size
Specify a field size for the for the returned image by entering a height and width in arcminutes. The default size is 5' x 5', which yields a FITS file of about 530 kbytes, or a GIF image of usually around 160 kbytes. (The maximum size, 60 arcminutes, produces an 8-megabyte FITS file.)

Select a compression method.
  • NONE - the FITS file will be delivered uncompressed.
  • Unix - The FITS file will be compressed with the Unix compress command.
  • gzip - The FITS file will be compressed with the gzip command.
Note If you select compress, make sure you append a .Z extension onto the name of the image before decompressing it; for gzip, append a .gz extension.