Menu for the package stsdas.analysis.dither

        avshift - Averages the shifts measured on the 4 WFPC chips.
           blot - Image sampling using interpolation (reverse "drizzling").
      crossdriz - Builds a set of cross-correlation images (shift + rotation).
          deriv - Take the absolute derivative of an image.
        driz_cr - Create cosmic ray mask based for dithered data.
        drizzle - Perform linear image reconstruction using "drizzling".
       dunlearn - Resets all task parameters to default values.
          gprep - Transform shifts for one WFPC2 chip into parameters for mosaicing all four chips.
      imextreme - Locates the maximum and minimum pixels in an image.
      loop_blot - Runs blot for a given list of input and output images.
      loop_driz - Runs drizzle for a list of input, output, and mask images.
      mask_head - Attach mask names to image headers; invert mask if requested
        offsets - Builds cross-correlation image (shift only).
         precor - Cosmic-ray processing.
        rotfind - Finds rotation angle from a set of cross-correlation images.
      shiftfind - Finds X,Y shifts in a cross-corelation image.
            sky - Sky processing by "crrej-like" algorithm.
          cdriz @ Pset for the 'offsets' task.
             dq @ Pset for the 'sky' task.
    wfpc2_chips @ Pset for 'avshift' and 'gprep' tasks.

For more information about the 'dither' package, type 
"help dither option=sysdoc".