NAME

       fors_subtract_sky - Subtract sky from scientific spectra

SYNOPSIS

       esorex fors_subtract_sky [OPTIONS] FILE.sof

DESCRIPTION

       This  recipe  is  used  to subtract the sky emission from unrebinned slit spectra. This is
       obtained by robust fitting (i.e., excluding the signal from possible point-like objects in
       slit)  of  the  emission  along the CCD columns within each spectrum). This method doesn´t
       work if extended objects are in slit (it really destroys the object spectra), and  is  not
       applicable  to  LSS  data.  The  input  scientific  frames  are  produced  by  the recipes
       fors_remove_bias and fors_flatfield.

       This recipe cannot be applied to LSS or long-slit like data (MOS/MXU with all slits at the
       same offset). No automatic recipe is available for this.

       Please refer to the FORS Pipeline User´s Manual for more details.

       In the table below the MXU acronym can be alternatively read as MOS, and SCI as STD.

       Input files:

         DO category:               Type:       Explanation:         Required:
         SCIENCE_UNBIAS_MXU
         or SCIENCE_UNFLAT_MXU
         or STANDARD_UNBIAS_MXU
         or STANDARD_UNFLAT_MXU     Calib       Frame with sky lines    Y
         CURV_COEFF_MXU             Calib       Spectral curvature      Y
         SLIT_LOCATION_MXU          Calib       Slit location on CCD    Y
         GRISM_TABLE                Calib       Grism table             .

       Output files:

         DO category:               Data type:  Explanation:
         UNMAPPED_SCI_MXU
         or UNMAPPED_STD_MXU        FITS image  Sky subtracted scientific frame
         UNMAPPED_SKY_SCI_MXU
         or UNMAPPED_SKY_STD_MXU    FITS image  Subtracted sky frame

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_subtract_sky.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_subtract_sky.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_subtract_sky.endwavelength
              [default = 0.0].

       --cosmics <bool>
              Eliminate cosmic rays hits (bool; default: False). The full name of this option for
              the EsoRex configuration file is fors.fors_subtract_sky.cosmics [default = False].

       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_normalise_flat(7),
       fors_photometry(7),   fors_img_screen_flat(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_subtract_sky 4.11.12

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