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The kmo_wave_cal recipe

kmo_wave_cal

Synopsis

Create a calibration frame encoding the spectral position (i.e. wavelength) of each pixel on the detector.

Description

This recipe creates the wavelength calibration frame needed for all three detectors. It must be called after the kmo_flat recipe, which generates the two spatial calibration frames needed in this recipe. As input a lamp-on frame, a lamp-off frame, the spatial calibration frames and the list with the reference arclines are required.An additional output frame is the resampled image of the reconstructed arc frame. All slitlets of all IFUs are aligned one next to the other. This frame serves for quality control. One can immediately see if the calibration was successful.

The lists of reference arclines are supposed to contain the lines for both available calibration arc-lamps, i.e. Argon and Neon. The list is supposed to be a F2L KMOS FITS file with three columns: 1. Reference wavelength 2. Relative strength 3. String either containing “Ar” or “Ne” The recipe extracts, based on the header keywords, either the applying argon and/or neon emission lines. Below are the plots of the emission lines for both argon and neon. The marked lines are the ones used for wavelength calibration.

Furthermore frames can be provided for several rotator angles. In this case the resulting calibration frames for each detector are repeatedly saved as extension for every angle.

Input files

DO                    KMOS
category              Type   Explanation                    Required #Frames
--------              -----  -----------                    -------- -------
ARC_ON                RAW    Arclamp-on exposure                Y        >=1
ARC_OFF               RAW    Arclamp-off exposure               Y          1
XCAL                  F2D    x calibration frame                Y          1
YCAL                  F2D    y calibration frame                Y          1
ARC_LIST              F2L    List of arclines                   Y          1
FLAT_EDGE             F2L    Fitted edge parameters             Y          1
REF_LINES             F2L    Reference line table               Y          1
WAVE_BAND             F2L    Table with start-/end-wavelengths  Y          1

Output files

DO                    KMOS
category              Type   Explanation
--------              -----  -----------
LCAL                  F2D    Wavelength calibration frame
                             (3 Extensions)
DET_IMG_WAVE          F2D    reconstructed arclamp-on exposure
                             (4 extensions: 3 detector images +
                             the arclines list table)

Constructor

cpl.Recipe("kmo_wave_cal")

Create an object for the recipe kmo_wave_cal.

import cpl
kmo_wave_cal = cpl.Recipe("kmo_wave_cal")

Parameters

kmo_wave_cal.param.order

The polynomial order to use for the fit of the wavelength solution. 0: (default) The appropriate order is chosen automatically depending on the waveband. Otherwise an order of 6 is recommended, except for IZ- band, there order 4 should be used (long; default: 0) [default=0].

kmo_wave_cal.param.dev_flip

Set this parameter to TRUE if the wavelengths are ascending on the detector from top to bottom. (bool; default: False) [default=False].

kmo_wave_cal.param.dev_disp

The expected dispersion of the wavelength in microns/pixel. If the default isn’t changed it will automatically be selected upon header keywords. (float; default: -1.0) [default=-1.0].

kmo_wave_cal.param.suppress_extension

Suppress arbitrary filename extension.(TRUE (apply) or FALSE (don’t apply) (bool; default: False) [default=False].

kmo_wave_cal.param.b_samples

The number of samples in wavelength for the reconstructed cube (long; default: 2048) [default=2048].

kmo_wave_cal.param.b_start

The lowest wavelength [um] to take into account when reconstructing (default of -1 sets the proper value for the actual band automatically) (float; default: -1.0) [default=-1.0].

kmo_wave_cal.param.b_end

The highest wavelength [um] to take into account when reconstructing (default of -1 sets the proper value for the actual band automatically) (float; default: -1.0) [default=-1.0].

The following code snippet shows the default settings for the available parameters.

import cpl
kmo_wave_cal = cpl.Recipe("kmo_wave_cal")

kmo_wave_cal.param.order = 0
kmo_wave_cal.param.dev_flip = False
kmo_wave_cal.param.dev_disp = -1.0
kmo_wave_cal.param.suppress_extension = False
kmo_wave_cal.param.b_samples = 2048
kmo_wave_cal.param.b_start = -1.0
kmo_wave_cal.param.b_end = -1.0

You may also set or overwrite some or all parameters by the recipe parameter param, as shown in the following example:

import cpl
kmo_wave_cal = cpl.Recipe("kmo_wave_cal")
[...]
res = kmo_wave_cal( ..., param = {"order":0, "dev_flip":False})

See also

cpl.Recipe for more information about the recipe object.

Bug reports

Please report any problems to Alex Agudo Berbel. Alternatively, you may send a report to the ESO User Support Department.