Determine spectral distortion models from flat field and arc lamp exposure.
This recipe is used to determine all the spectral distortions and transformations from an arc lamp exposure and a master flat field produced by the recipe vmspflat.
DO category: Type: Explanation: Required:
MOS_ARC_SPECTRUM Raw Arc lamp exposure Y
MASTER_BIAS Calib Master bias Y
MASTER_DARK Calib Master dark .
MOS_MASTER_SCREEN_FLAT Calib Normalised flat field .
MOS_COMBINED_SCREEN_FLAT Calib Combined flat field .
GRISM_TABLE Calib Grism table Y
LINE_CATALOG Calib Line catalog Y
EXTRACT_TABLE Calib Extraction table .
CCD_TABLE Calib Bad pixel table .
DO category: Data type: Explanation:
EXTRACT_TABLE FITS table Extraction table
MOS_ARC_SPECTRUM_EXTRACTED FITS image Sky subtracted slit spectra
(none) PAF Distortion models
At least one raw arc lamp exposure should be present in the input SOF.
The normalised and the combined flat fields are the products of the recipe vmspflat run on flat field data obtained with the same mask.
Neither of them is required for running vmspcaldisp, but if a combined flat field is not given then no spectral curvature model can be computed, and a first-guess is used in its place. A normalised master flat field needs to be specified only if a flat field correction is requested.
The bad pixel table needs to be specified only if the cleaning of bad pixels is requested.
An extraction table generated from previous runs might be input to the recipe, in order to iterate the modeling of the spectral distortions.
The grism table contains necessary information to control the way spectra are extracted and the determination of the distortion models.
The vmspcaldisp recipe gets from the grism table the wavelength that should be used as reference (header entry PRO WLEN CEN), and the spectrum extension in CCD pixels above and below the position of the reference wavelength (header entries PRO SPECT LLEN LO and PRO SPECT LLEN HI). Other parameters, used in the construction of the extracted arc lamp slit spectra, are the start and the end wavelength of the image containing the extracted spectra (header entries PRO WLEN START and PRO WLEN END), and the step of the sampling along the dispersion direction (header entry PRO WLEN INC).
The primary recipe product is the extraction table, that contains information about the local modelling of spectral distortions.
A secondary product of the vmspcaldisp recipe is the image of extracted slit spectra, that allows a visual check of the distortion models quality. A last product is the PAF file carrying all the information related to the spectral distortions. This PAF file is copied (or moved) to the product directory, and it is identical to the IWS configuration file MOS_wavecal_G_Q.cmf where Q indicates the VIMOS quadrant number, and G the grism name) that is created in the directory where vmspcaldisp is launched.
Create an object for the recipe vmspcaldisp.
import cpl
vmspcaldisp = cpl.Recipe("vmspcaldisp")
Bias removal method. (str; default: ‘Zmaster’) [default=”Zmaster”].
Extra pixels from expected position of spectrum edge in spectral extraction. (long; default: 10) [default=10].
Refine Inverse Dispersion Solution. (bool; default: False) [default=False].
Size of search window around expected arc line positions. (long; default: 10) [default=10].
Flat field correction for input arc lamp frames. (bool; default: False) [default=False].
Bad pixel correction on arc lamp image. (bool; default: False) [default=False].
Cosmic ray events cleaning in arc lamp image. (bool; default: False) [default=False].
Arc line identification method. (str; default: ‘FirstGuess’) [default=”FirstGuess”].
Threshold for peak detection. (float; default: 500.0) [default=500.0].
Arc lamp 2D extraction according to computed Local or Global IDS. (str; default: ‘Local’) [default=”Local”].
Model wavelength solution within each slit. (bool; default: True) [default=True].
Order of polynomial for wavelength solution modeling within each slit. (long; default: 0) [default=0].
Compute QC1 parameters. (bool; default: True) [default=True].
The following code snippet shows the default settings for the available parameters.
import cpl
vmspcaldisp = cpl.Recipe("vmspcaldisp")
vmspcaldisp.param.BiasMethod = "Zmaster"
vmspcaldisp.param.Fuzz = 10
vmspcaldisp.param.RefineIDS = False
vmspcaldisp.param.ExtractionWindow = 10
vmspcaldisp.param.ApplyFlatField = False
vmspcaldisp.param.CleanBadPixel = False
vmspcaldisp.param.CleanCosmic = False
vmspcaldisp.param.LineIdent = "FirstGuess"
vmspcaldisp.param.LineIdentLevel = 500.0
vmspcaldisp.param.ArcExtraction = "Local"
vmspcaldisp.param.ModelSlit = True
vmspcaldisp.param.ModelSlitOrder = 0
vmspcaldisp.param.ComputeQC = True
You may also set or overwrite some or all parameters by the recipe parameter param, as shown in the following example:
import cpl
vmspcaldisp = cpl.Recipe("vmspcaldisp")
[...]
res = vmspcaldisp( ..., param = {"BiasMethod":"Zmaster", "Fuzz":10})
See also
cpl.Recipe for more information about the recipe object.
Please report any problems to ESO VIMOS Pipeline Team and VIMOS Consortium. Alternatively, you may send a report to the ESO User Support Department.
This file is part of the VIMOS Instrument Pipeline Copyright (C) 2002-2005 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
Code author: ESO VIMOS Pipeline Team and VIMOS Consortium <usd-help@eso.org>