ST-ECF package to process NICMOS Grism images:

       makeasn     - create calnicb type association file from wcs
       alignasn    - update shifts in one or two associations from star coords
       markback    - mark the regions to be used for the statistics in 
                     asncombine
       asncombine  - subtract background and combine images in asocication
       asnexam     - display images in asociations
       asnphot     - plot mag as function of sub-pixel position 
       makeprfcorr - create sub-pixel response function combined image
                     created with asncombine
       makeflat    - create flatfields appropiate for the output images
                     of asncombine

Type "help command" for more information on tasks in the 'nictools' package.