The muse_exp_combine recipe



Combine several exposures into one datacube.


Sort reduced pixel tables, one per exposure, by exposure and combine them with applied weights into one final datacube.



Create an object for the recipe muse_exp_combine.

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


Select output product(s) to save. Can contain one or more of “cube” (output cube and associated images; if this is not given, no resampling is done at all) or “combined” (fully reduced and combined pixel table for the full set of exposures; this is useful, if the final resampling step is to be done again separately). If several options are given, they have to be comma-separated. (str; default: ‘cube’) [default=”cube”].


The resampling technique to use for the final output cube. (str; default: ‘drizzle’) [default=”drizzle”].


Horizontal step size for resampling (in arcsec or pixel). The following defaults are taken when this value is set to 0.0: 0.2’’ for WFM, 0.025’’ for NFM, 1.0 if data is in pixel units. (float; default: 0.0) [default=0.0].


Vertical step size for resampling (in arcsec or pixel). The following defaults are taken when this value is set to 0.0: 0.2’’ for WFM, 0.025’’ for NFM, 1.0 if data is in pixel units. (float; default: 0.0) [default=0.0].


Wavelength step size (in Angstrom). Natural instrument sampling is used, if this is 0.0 (float; default: 0.0) [default=0.0].


Type of statistics used for detection of cosmic rays during final resampling. “iraf” uses the variance information, “mean” uses standard (mean/stdev) statistics, “median” uses median and the median median of the absolute median deviation. (str; default: ‘median’) [default=”median”].


Sigma rejection factor to use for cosmic ray rejection during final resampling. A zero or negative value switches cosmic ray rejection off. (float; default: 10.0) [default=10.0].


Critical radius for the “renka” resampling method. (float; default: 1.25) [default=1.25].


Pixel down-scaling factor for the “drizzle” resampling method. Up to three, comma-separated, floating-point values can be given. If only one value is given, it applies to all dimensions, two values are interpreted as spatial and spectral direction, respectively, while three are taken as horizontal, vertical, and spectral. (str; default: ‘0.6,0.6’) [default=”0.6,0.6”].


Number of adjacent pixels to take into account during resampling in all three directions (loop distance); this affects all resampling methods except “nearest”. (int; default: 1) [default=1].


Type of output file format, “Cube” is a standard FITS cube with NAXIS=3 and multiple extensions (for data and variance). The extended “x” formats include the reconstructed image(s) in FITS image extensions within the same file. “sdpCube” does some extra calculations to create FITS keywords for the ESO Science Data Products. (str; default: ‘Cube’) [default=”Cube”].


Type of weighting scheme to use when combining multiple exposures. “exptime” just uses the exposure time to weight the exposures, “fwhm” uses the best available seeing information from the headers as well, “header” queries ESO.DRS.MUSE.WEIGHT of each input file instead of the FWHM, and “none” preserves an existing weight column in the input pixel tables without changes. (str; default: ‘exptime’) [default=”exptime”].


The filter name(s) to be used for the output field-of-view image. Each name has to correspond to an EXTNAME in an extension of the FILTER_LIST file. If an unsupported filter name is given, creation of the respective image is omitted. If multiple filter names are given, they have to be comma separated. (str; default: ‘white’) [default=”white”].


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


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

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

import cpl
muse_exp_combine = cpl.Recipe("muse_exp_combine") = "cube"
muse_exp_combine.param.resample = "drizzle"
muse_exp_combine.param.dx = 0.0
muse_exp_combine.param.dy = 0.0
muse_exp_combine.param.dlambda = 0.0
muse_exp_combine.param.crtype = "median"
muse_exp_combine.param.crsigma = 10.0
muse_exp_combine.param.rc = 1.25
muse_exp_combine.param.pixfrac = "0.6,0.6"
muse_exp_combine.param.ld = 1
muse_exp_combine.param.format = "Cube"
muse_exp_combine.param.weight = "exptime"
muse_exp_combine.param.filter = "white"
muse_exp_combine.param.lambdamin = 4000.0
muse_exp_combine.param.lambdamax = 10000.0

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

import cpl
muse_exp_combine = cpl.Recipe("muse_exp_combine")
res = muse_exp_combine( ..., param = {"save":"cube", "resample":"drizzle"})

See also

cpl.Recipe for more information about the recipe object.

Bug reports

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