| Description: The name of the flat field calibration file used to correct for pixel-to-pixel sensitivity variations in the detector. These files are stored in the "slope" subdirectory of the calibration support directory and contain multiplicative correction factors for each pixel. The appropriate file is selected automatically by CISSCAL based on two criteria: the filter combination used for the observation, and the temperature range of the optics (-5°C and below, -5°C to 25°C, or above 25°C). The selection is managed through a database file called slope_db.tab, which maps filter combinations and temperature ranges to specific slope filenames. The slope files themselves are in VICAR format and contain a 1024x1024 array (for full-frame images) of floating-point correction factors that are divided into the image during the flat field correction step. |