Other files used by the PROS software, besides IRAF array images, are the PLIO masks and TABLE files . These files can be used to filter selected regions in the image, to accept only regions in the image that have been uniformly exposed , or to correct the images for vignetting.
N.B.: Note that the PLIO masks are appropriate only for the reference image used to create them, i.e. , any change in the dimension of the reference file requires that a new mask be made. Tabular data output from PROS tasks are written to TABLE files. A set of tools to view, plot, and manipulate tables is available in the TABLES package.