The muse_create_sky recipe

muse_create_sky

Synopsis

Create night sky model from selected pixels of an exposure of empty sky.

Description

This recipe creates the continuum and the atmospheric transition line spectra of the night sky from the data in a pixel table(s) belonging to one exposure of (mostly) empty sky.

Constructor

cpl.Recipe("muse_create_sky")

Create an object for the recipe muse_create_sky.

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

Parameters

muse_create_sky.param.fraction

Fraction of the image (without the ignored part) to be considered as sky. If an input sky mask is provided, the fraction is applied to the regions within the mask. If the whole sky mask should be used, set this parameter to 1. (float; default: 0.75) [default=0.75].

muse_create_sky.param.ignore

Fraction of the image to be ignored. If an input sky mask is provided, the fraction is applied to the regions within the mask. If the whole sky mask should be used, set this parameter to 0. (float; default: 0.05) [default=0.05].

muse_create_sky.param.sampling

Spectral sampling of the sky spectrum [Angstrom]. (float; default: 0.3125) [default=0.3125].

muse_create_sky.param.csampling

Spectral sampling of the continuum spectrum [Angstrom]. (float; default: 0.3125) [default=0.3125].

muse_create_sky.param.crsigma

Sigma level clipping for cube-based and spectrum-based CR rejection. This has to be a string of two comma-separated floating-point numbers. The first value gives the sigma-level rejection for cube-based CR rejection (using “median”, see muse_scipost), the second value the sigma-level for spectrum-based CR cleaning. Both can be switched off, by passing zero or a negative value. (str; default: ‘15.,15.’) [default=”15.,15.”].

muse_create_sky.param.lambdamin

Cut off the data below this wavelength after loading the pixel table(s). (float; default: 4000.0) [default=4000.0].

muse_create_sky.param.lambdamax

Cut off the data above this wavelength after loading the pixel table(s). (float; default: 10000.0) [default=10000.0].

muse_create_sky.param.lambdaref

Reference wavelength used for correction of differential atmospheric refraction. The R-band (peak wavelength ~7000 Angstrom) that is usually used for guiding, is close to the central wavelength of MUSE, so a value of 7000.0 Angstrom should be used if nothing else is known. A value less than zero switches DAR correction off. (float; default: 7000.0) [default=7000.0].

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

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

muse_create_sky.param.fraction = 0.75
muse_create_sky.param.ignore = 0.05
muse_create_sky.param.sampling = 0.3125
muse_create_sky.param.csampling = 0.3125
muse_create_sky.param.crsigma = "15.,15."
muse_create_sky.param.lambdamin = 4000.0
muse_create_sky.param.lambdamax = 10000.0
muse_create_sky.param.lambdaref = 7000.0

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

import cpl
muse_create_sky = cpl.Recipe("muse_create_sky")
[...]
res = muse_create_sky( ..., param = {"fraction":0.75, "ignore":0.05})

See also

cpl.Recipe for more information about the recipe object.

Bug reports

Please report any problems to Ole Streicher. Alternatively, you may send a report to the ESO User Support Department.