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NAME

       fors_normalise_flat - Normalise master flat spectrum

SYNOPSIS

       esorex fors_normalise_flat [OPTIONS] FILE.sof

DESCRIPTION

       This  recipe is used to normalise a master flat field frame dividing it by its large scale
       illumination trend. This recipe can be applied both to generic multi-slit (MOS/MXU) and to
       long  slit  exposures  (either  LSS, or LSS-like MOS/MXU), even if different normalisation
       methods are applied in such different cases. The input master  flat  field  image  is  the
       product of the recipe fors_flat. The input spectral curvature table, product of the recipe
       fors_detect_spectra, is only required in the case of multi-slit data.

       In the case of multi-slit data, the flat field spectra are  spatially  rectified,  heavily
       smoothed,  and  then  mapped back on the CCD. Then the master flat image is divided by its
       smoothed counterpart. The smoothing may be obtained either by applying  a  running  median
       filter  of  specified  sizes,  or  by  polynomial  fitting  along the dispersion direction
       performed independently for each row of the spatially remapped spectra.

       In the case of long-slit data, the smoothing can still be obtained either  by  applying  a
       running  median  filter  or  by  polynomial  fitting,  but  the polynomial fitting will be
       performed along the spatial direction, for each column of the spectrum.

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

       Input files:

         DO category:               Type:       Explanation:         Required:
         MASTER_SCREEN_FLAT_MXU     Calib       Master flat frame       Y
         DISP_COEFF_MXU             Calib       Wavelength calibration  Y
         CURV_COEFF_MXU             Calib       Spectral curvature      .

         SLIT_LOCATION_MXU          Calib       Slit detection          .

         GRISM_TABLE                Calib       Grism table             Y

       Output files:

         DO category:               Data type:  Explanation:
         MASTER_NORM_FLAT_MXU       FITS image  Normalised flat field

OPTIONS

       --dispersion <float>
              Expected spectral dispersion (Angstrom/pixel) (float; default: 0.0). The full  name
              of     this     option     for     the     EsoRex     configuration     file     is
              fors.fors_normalise_flat.dispersion [default = 0.0].

       --startwavelength <float>
              Start wavelength in spectral extraction (float; default: 0.0).  The  full  name  of
              this      option      for      the      EsoRex      configuration      file      is
              fors.fors_normalise_flat.startwavelength [default = 0.0].

       --endwavelength <float>
              End wavelength in spectral extraction (float; default: 0.0). The full name of  this
              option  for the EsoRex configuration file is fors.fors_normalise_flat.endwavelength
              [default = 0.0].

       --spa_polydegree <int>
              Polynomial degree for the flat field fitting along spatial direction (int; default:
              -1).   The  full  name  of  this  option  for  the  EsoRex  configuration  file  is
              fors.fors_normalise_flat.spa_polydegree [default = -1].

       --sradius <int>
              Smooth box radius for flat field along spatial direction (used if  spa_knots  <  0)
              (int;  default: 10). The full name of this option for the EsoRex configuration file
              is fors.fors_normalise_flat.sradius [default = 10].

       --disp_nknots <int>
              Number of knots in flat field fitting  splines  along  dispersion  direction  (int;
              default:  -1).  The  full  name of this option for the EsoRex configuration file is
              fors.fors_normalise_flat.disp_nknots [default = -1].

       --dradius <int>
              Smooth box radius for flat field along dispersion direction  (if  disp_knots  <  0)
              (int;  default: 10). The full name of this option for the EsoRex configuration file
              is fors.fors_normalise_flat.dradius [default = 10].

       --splfit_threshold <float>
              Threshold percentage for flat spline fittingwith respect  to  the  maximum  (float;
              default:  0.01).  The full name of this option for the EsoRex configuration file is
              fors.fors_normalise_flat.splfit_threshold [default = 0.01].

       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_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_flatfield(7),  fors_img_science(7),  fors_img_screen_flat(7),   fors_img_sky_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)

VERSION

       fors_normalise_flat 5.3.32

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