Provided by: cpl-plugin-fors-doc_4.11.12+dfsg-3_all 
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
CURV_COEFF_MXU Calib Spectral curvature .
SLIT_LOCATION_MXU Calib Spectral curvature .
GRISM_TABLE Calib Grism table .
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_nknots <long>
Number of knots in flat field fitting splines along spatial direction (long;
default: -1). The full name of this option for the EsoRex configuration file is
fors.fors_normalise_flat.spa_nknots [default = -1].
--sradius <long>
Smooth box radius for flat field along spatial direction (used if spa_knots < 0)
(long; default: 10). The full name of this option for the EsoRex configuration file
is fors.fors_normalise_flat.sradius [default = 10].
--disp_nknots <long>
Number of knots in flat field fitting splines along dispersion direction (long;
default: -1). The full name of this option for the EsoRex configuration file is
fors.fors_normalise_flat.disp_nknots [default = -1].
--dradius <long>
Smooth box radius for flat field along dispersion direction (if disp_knots < 0)
(long; 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-4.7.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_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_normalise_flat 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