NAME

       fors_img_screen_flat - Compute master screen flat frame

SYNOPSIS

       esorex fors_img_screen_flat [OPTIONS] FILE.sof

DESCRIPTION

       After  bias  subtraction,  the  input flat field frames are combined using the given stack
       method. The  combined  frame  is  finally  normalised  dividing  it  by  its  large  scale
       illumination  trend.  The large scale trend is obtained by applying a median filter with a
       large kernel. To avoid boundary  effects,  the  median  filter  is  applied  only  to  the
       specified region.

       The overscan regions, if present, are removed from the result.

       Input files:

         DO category:               Type:       Explanation:         Required:
         SCREEN_FLAT_IMG            Raw         Screen flat field    Y
         MASTER_BIAS                Raw         Master bias          Y

       Output files:

         DO category:               Data type:  Explanation:
         MASTER_SCREEN_FLAT_IMG     FITS image  Master screen flat field

OPTIONS

       --stack_method <str>
              Frames  combination  method (str; default: ´average´). The full name of this option
              for  the  EsoRex  configuration  file   is   fors.fors_img_screen_flat.stack_method
              [default = average].

       --minrejection <long>
              Number  of  lowest  values to be rejected (long; default: 1). The full name of this
              option for the EsoRex configuration file is  fors.fors_img_screen_flat.minrejection
              [default = 1].

       --maxrejection <long>
              Number  of  highest values to be rejected (long; default: 1). The full name of this
              option for the EsoRex configuration file is  fors.fors_img_screen_flat.maxrejection
              [default = 1].

       --klow <float>
              Low  threshold in ksigma method (float; default: 3.0). The full name of this option
              for the EsoRex configuration  file  is  fors.fors_img_screen_flat.klow  [default  =
              3.0].

       --khigh <float>
              High threshold in ksigma method (float; default: 3.0). The full name of this option
              for the EsoRex configuration file  is  fors.fors_img_screen_flat.khigh  [default  =
              3.0].

       --kiter <long>
              Max  number  of  iterations in ksigma method (long; default: 999). The full name of
              this option for the EsoRex configuration  file  is  fors.fors_img_screen_flat.kiter
              [default = 999].

       --xradius <long>
              Median filter x radius (unbinned pixels) (long; default: 50). The full name of this
              option for  the  EsoRex  configuration  file  is  fors.fors_img_screen_flat.xradius
              [default = 50].

       --yradius <long>
              Median filter y radius (unbinned pixels) (long; default: 50). The full name of this
              option for  the  EsoRex  configuration  file  is  fors.fors_img_screen_flat.yradius
              [default = 50].

       --degree <long>
              Degree  of fitting polynomial (long; default: -1). The full name of this option for
              the EsoRex configuration file is fors.fors_img_screen_flat.degree [default = -1].

       --sampling <long>
              Sampling interval for fitting (long; default: 100). The full name  of  this  option
              for  the EsoRex configuration file is fors.fors_img_screen_flat.sampling [default =
              100].

       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-4.7.pdf

       An   overview   over   the   existing   ESO  pipelines  can  be  found  on  the  web  page
       http://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
       http://packages.python.org/python-cpl/index.html for further information.

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

VERSION

       fors_img_screen_flat 4.11.12

AUTHOR

       Jonas M. Larsen <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) 2002-2011
       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