PDS_VERSION_ID         = PDS3
RECORD_TYPE            = STREAM
OBJECT                 = TEXT
  PUBLICATION_DATE     = 2018-01-09
  INTERCHANGE_FORMAT   = ASCII
  NOTE                 = "Description of dustring directory contents."
END_OBJECT             = TEXT
END

Dustring directory:
-------------------

This directory contains VICAR-image files used to correct for dustrings
in the NAC that are not found in the slope files created during ground 
calibration.

The file nac_dustring_1308947228.img was derived from Venus flyby data.

The file nac_mottle_1444733393.img is a map of the "mottling" flatfield 
pattern found in all NAC images after SCLK=1444733393.

The file nac_dustring_aboff.img corrects the bright ring located at sample =
887, line = 388 (already present in the slope files) for images where 
anti-blooming mode is turned OFF.

All other files (*dustring*.img) include dust rings derived from Titan 
atmosphere images, and are cumulative with time. These files incorporate the 
Venus-derived dust ring but not the mottle map.