Provided by: cpl-plugin-fors-doc_4.11.12+dfsg-3_all 
NAME
fors_trace_flat - Determine spectral curvature model
SYNOPSIS
esorex fors_trace_flat [OPTIONS] FILE.sof
DESCRIPTION
This recipe is used to trace the edges of MOS/MXU flat field slit spectra and determine
the spectral curvature solution. The input master flat field image, product of the recipe
fors_flat, is expected to be oriented with horizontal dispersion direction and red
wavelengths on the right side.
The input slits location table should be the product of the recipe fors_detect_spectra.
The input master flat image is shifted one pixel down and is subtracted from the original
image. The result is a vertical gradient map. Next, the negative values are forced
positive, to obtain an absolute gradient map. The map is passed with a horizontal median
filter, and after that the gradient peaks are traced starting from the slits positions
listed in the input slits location table. The number of pixels to the left and to the
right of the reference pixel is trivially derived from the specified spectral range and
spectral dispersion.
The output spectral curvature table contains the coefficients of the polynomial fitting of
the found traces, while the output trace table contains the traced spectral edges
positions in CCD (Y) coordinates for each spectrum, and their comparison with their
modeling. A spatial map is also created, where to each CCD pixel is assigned the value of
the spatial coordinate along the slit (in pixel). For more details please refer to the
FORS Pipeline User´s Manual.
Note that specifying an input GRISM_TABLE will set some of the recipe configuration
parameters to default values valid for a particular grism.
Again, see the pipeline manual for more details.
In the table below the MXU acronym can be alternatively read as MOS.
Input files:
DO category: Type: Explanation: Required:
MASTER_SCREEN_FLAT_MXU Calib Master flat frame Y
SLIT_LOCATION_DETECT_MXU Calib Slits location Y
GRISM_TABLE Calib Grism table .
Output files:
DO category: Data type: Explanation:
CURV_TRACES_MXU FITS table Flat field tracings
CURV_COEFF_MXU FITS table Spectral curvature table
SPATIAL_MAP_MXU FITS image Map of spatial coordinate
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_trace_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_trace_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_trace_flat.endwavelength
[default = 0.0].
--cdegree <long>
Degree of spectral curvature polynomial (long; default: 0). The full name of this
option for the EsoRex configuration file is fors.fors_trace_flat.cdegree [default =
0].
--cmode <long>
Interpolation mode of curvature solution applicable to MOS-like data (0 = no
interpolation, 1 = fill gaps, 2 = global model) (long; default: 1). The full name
of this option for the EsoRex configuration file is fors.fors_trace_flat.cmode
[default = 1].
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_img_screen_flat(7), fors_dark(7),
fors_subtract_sky_lss(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_trace_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