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fors_flatfield - Flat field correction of input frame


esorex fors_flatfield [OPTIONS] FILE.sof


This recipe is used to divide the input frame by the normalised flat field frame produced by recipe fors_normalise_flat. The input frame must be already bias subtracted (e.g., by recipe fors_remove_bias).

In the table below the MXU acronym can be alternatively read as MOS and LSS.

Input files:

DO category: Type: Explanation: Required: SCIENCE_UNBIAS_MXU or STANDARD_UNBIAS_MXU Raw Bias subtracted frame Y MASTER_NORM_FLAT_MXU Calib Normalised flat frame Y

Output files:

DO category: Data type: Explanation: SCIENCE_UNFLAT_MXU or STANDARD_UNFLAT_MXU FITS image Flat field corrected frame


Note that it is possible to create a configuration file containing these options, along with suitable default values. Please refer to the details provided by the 'esorex --help' command.


The full documentation for the fors pipeline can be downloaded as a PDF file using the following URL:

An overview over the existing ESO pipelines can be found on the web page

Basic documentation about the EsoRex program can be found at the esorex (1) man page.

It is possible to call the pipelines from python using the python-cpl package. See for further information.

The other recipes of the fors pipeline are fors_align_sky(7), fors_align_sky_lss(7), fors_bias(7), fors_calib(7), fors_config(7), fors_dark(7), fors_detect_objects(7), fors_detect_spectra(7), fors_extract(7), fors_extract_objects(7), fors_extract_slits(7), fors_img_science(7), fors_img_screen_flat(7), fors_img_sky_flat(7), fors_normalise_flat(7), fors_photometry(7), fors_pmos_calib(7), fors_pmos_extract(7), fors_pmos_science(7), fors_remove_bias(7), fors_resample(7), fors_science(7), fors_spec_mflat(7), fors_subtract_sky(7), fors_subtract_sky_lss(7), fors_sumflux(7), fors_trace_flat(7), fors_wave_calib(7), fors_wave_calib_lss(7), fors_zeropoint(7)


fors_flatfield 5.3.32


Carlo Izzo <>


Please report any problems to Alternatively, you may send a report to the ESO User Support Department <>.


This file is currently part of the FORS Instrument Pipeline Copyright (C) 2002-2010 European Southern Observatory

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

5.3.32 fors_flatfield