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petff -- flat field the contents of a Pixel Extraction Table (PET)
petff grism config
- Name of grism/prism image.
- Filename of grism/prism extraction configuration file.
- (back = no) [boolean]
- Specify whether or not to apply the flat-field (FF) to the background Pixel Extraction Table (BPET).
- (ffname = "") [string]
- Name to use for the output flat field cube file instead of the default.
This tasks uses a flat-field calibration file to flat-field the content of a Pixel Extraction Table (PET). The wavelength of a pixel is used in conjunction with a flat-fielding data cube containing the coefficents of a polynomial which can be used to compute at each pixel (x,y):
FF(x,y,lambda) = a_0(x,y) + a_1(x,y)*lambda + .. +a_i * lambda^iThe coefficients a_0(x,y) are stored in the first data extention of the flat-field cube, a_1(x,y) in the second, etc... The name of the flat-field cube is read from the aXe configuration file.
Note that that flat-fielding should be applied to both the OPET and the BPET separately so that, when subtracted, the information contained in the BPET has been flat-fielded with the same flat-field as the OPET (which contains counts of objects plus counts from the background).
aXe tasks use default names for input and output files based on the given name of the "grism" image. For this task the default input PET would be called <grism-rootname>_<science extension>.PET.fits and will be flat-fielded "in place" using the flat field cube defined in the main configuration file.
ax> petff test_grism_1.fits SLIM.conf.test.0Perform in-place flat-fielding of the PET associated with the grism data file test_grism_1.fits. Use configuration parameters from the file SLIM.conf.test.0.
Refer to manual for more detailed information about using this aXe task: