---
name: "fors_flatfield"
section: "7"
platform: "linux"
package: "cpl-plugin-fors-doc"
version: "5.5.6+dfsg-4"
release: "Debian 11 (Bullseye)"
platforms: ["linux"]
url: "https://new.carta.tech/fors_flatfield"
---

# fors\_flatfield(7)

Flat field correction of input frame

## NAME

fors\_flatfield - Flat field correction of input frame

## SYNOPSIS

esorex **fors\_flatfield** \[OPTIONS\] FILE.sof

## DESCRIPTION

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

## OPTIONS

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.

## SEE ALSO

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

-

  **ftp://ftp.eso.org/pub/dfs/pipelines/fors/fors-pipeline-manual-4.9.pdf**

An overview over the existing ESO pipelines can be found on the web page **https://www.eso.org/sci/software/pipelines/**.

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 **https://packages.python.org/python-cpl/index.html** for further information.

The other recipes of the fors pipeline are [*fors\_align\_sky*(7)](/fors_align_sky/7.md), [*fors\_align\_sky\_lss*(7)](/fors_align_sky_lss/7.md), [*fors\_bias*(7)](/fors_bias/7.md), [*fors\_calib*(7)](/fors_calib/7.md), [*fors\_config*(7)](/fors_config/7.md), [*fors\_dark*(7)](/fors_dark/7.md), [*fors\_detect\_objects*(7)](/fors_detect_objects/7.md), [*fors\_detect\_spectra*(7)](/fors_detect_spectra/7.md), [*fors\_extract*(7)](/fors_extract/7.md), [*fors\_extract\_objects*(7)](/fors_extract_objects/7.md), [*fors\_extract\_slits*(7)](/fors_extract_slits/7.md), [*fors\_img\_science*(7)](/fors_img_science/7.md), [*fors\_img\_screen\_flat*(7)](/fors_img_screen_flat/7.md), [*fors\_img\_sky\_flat*(7)](/fors_img_sky_flat/7.md), [*fors\_normalise\_flat*(7)](/fors_normalise_flat/7.md), [*fors\_photometry*(7)](/fors_photometry/7.md), [*fors\_pmos\_calib*(7)](/fors_pmos_calib/7.md), [*fors\_pmos\_extract*(7)](/fors_pmos_extract/7.md), [*fors\_pmos\_science*(7)](/fors_pmos_science/7.md), [*fors\_remove\_bias*(7)](/fors_remove_bias/7.md), [*fors\_resample*(7)](/fors_resample/7.md), [*fors\_science*(7)](/fors_science/7.md), [*fors\_spec\_mflat*(7)](/fors_spec_mflat/7.md), [*fors\_subtract\_sky*(7)](/fors_subtract_sky/7.md), [*fors\_subtract\_sky\_lss*(7)](/fors_subtract_sky_lss/7.md), [*fors\_sumflux*(7)](/fors_sumflux/7.md), [*fors\_trace\_flat*(7)](/fors_trace_flat/7.md), [*fors\_wave\_calib*(7)](/fors_wave_calib/7.md), [*fors\_wave\_calib\_lss*(7)](/fors_wave_calib_lss/7.md), [*fors\_zeropoint*(7)](/fors_zeropoint/7.md)

## VERSION

fors\_flatfield 5.5.6

## AUTHOR

Carlo Izzo \<usd-help@eso.org\>

## BUG REPORTS

Please report any problems to usd-help@eso.org. Alternatively, you may send a report to the ESO User Support Department \<usd-help@eso.org\>.

## LICENSE

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