• avshift - Averages the shifts measured on the 4 WFPC chips.
• blot - Image sampling using interpolation (reverse "drizzling").
• cgsky - Compute sky using `gsky' plus a correction for histogram truncation.
• crossdriz - Builds a set of cross-correlation images (shift
• 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.
• gsky - Compute sky using the same mode algorithm used in task "crrej".
• 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.
• multidrizzle - Automated task for performing cosmic-ray rejection
• mask_head - Attach mask names to image headers; invert mask if requested
• offsets - Builds cross-correlation image (shift only).
• precor - Cosmic-ray processing.
• pydrizzle - Automated Python-based interface for the "drizzle" task
• 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.\
• tran - Transform coordinates taking into account distortion
• tranback - Transform an X,Y position from output to input pixel position using the same conventions as drizzle
• traxy - Transform an X,Y position from input to output pixel position using the same conventions as drizzle
• tweakshifts - Compute residual shifts between images
• wcs2dr - Convert WCS header information into drizzle parameters for image registration
• xytosky - Translate a 2-D image pixel coordinate to right ascension and declination, optionally applying the distortion coefficients for the detector.
• 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".