Provided by: cpl-plugin-fors-doc_5.5.7+dfsg-2build1_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 <int>
Degree of spectral curvature polynomial (int; default: 0). The full name of this option for the
EsoRex configuration file is fors.fors_trace_flat.cdegree [default = 0].
--cmode <int>
Interpolation mode of curvature solution applicable to MOS-like data (0 = no interpolation, 1 =
fill gaps, 2 = global model) (int; 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-4.9.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_normalise_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_wave_calib(7), fors_wave_calib_lss(7), fors_zeropoint(7)
VERSION
fors_trace_flat 5.5.7
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
fors_trace_flat 5.5.7 FORS_TRACE_FLAT(7)