MUSE_ASTROMETRY(7) muse recipes MUSE_ASTROMETRY(7)

muse_astrometry - Compute an astrometric solution.

esorex muse_astrometry [OPTIONS] FILE.sof

Merge pixel tables from all IFUs, apply correction for differential atmospheric refraction (when necessary), optionally apply flux calibration and telluric correction (if the necessary input data was given), and resample the data from all exposures into a datacube. Use the cube to detect objects which are then matched to their reference positions from which a two-dimensional WCS solution is computed. There are two pattern matching algorithm implemented, which can be selected by chosing a positive or zero value of faccuracy. In the first method (with a positive value of faccuracy), start using the search radius, and iteratively decrease it, until no duplicate detections are identified any more. Similarly, iterate the data accuracy (decrease it downwards from the mean positioning error) until matches are found. Remove the remaining unidentified objects. The second method (when faccuracy is set to zero), iterates through all quadruples in both the detected objects and the catalogue, calculates the transformation and checks whether more than 80% of the detections match a catalog entry within the radius. The main output is the ASTROMETRY_WCS file which is a bare FITS header containing the world coordinate solution. The secondary product is DATACUBE_ASTROMETRY, it is not needed for further processing but can be used for verification and debugging. It contains the reconstructed cube and two images created from it in further FITS extensions: a white-light image and the special image created from the central planes of the cube used to detect and centroid the stars (as well as its variance).

Centroiding method to use for objects in the field of view. "gaussian" and "moffat" use 2D fits to derive the centroid, "box" is a simple centroid in a square box. (str; default: ´moffat´). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.centroid [default = moffat].
Source detection sigma level to use. If this is negative, values between its absolute and 1.0 are tested with a stepsize of 0.1, to find an optimal solution. (float; default: 1.5). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.detsigma [default = 1.5].
Initial radius in pixels for pattern matching identification in the astrometric field. (float; default: 3.0). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.radius [default = 3.0].
Factor of initial accuracy relative to mean positional accuracy of the measured positions to use for pattern matching. If this is set to zero, use the quadruples based method. (float; default: 0.0). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.faccuracy [default = 0.0].
Number of iterations of the astrometric fit. (int; default: 2). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.niter [default = 2].
Rejection sigma level of the astrometric fit. (float; default: 3.0). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.rejsigma [default = 3.0].
Center of rotation of the instrument, given as two comma-separated floating point values in pixels. (str; default: ´-0.01,-1.20´). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.rotcenter [default = -0.01,-1.20].
Cut off the data below this wavelength after loading the pixel table(s). (float; default: 4000.0). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.lambdamin [default = 4000.0].
Cut off the data above this wavelength after loading the pixel table(s). (float; default: 10000.0). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.lambdamax [default = 10000.0].
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). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.lambdaref [default = 7000.0].
Carry out a check of the theoretical DAR correction using source centroiding. If "correct" it will also apply an empirical correction. (str; default: ´none´). The full name of this option for the EsoRex configuration file is muse.muse_astrometry.darcheck [default = none].

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.

The full documentation for the muse pipeline can be downloaded as a PDF file using the following URL:

ftp://ftp.eso.org/pub/dfs/pipelines/muse/muse-pipeline-cookbook-2.8.7.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 muse pipeline are muse_ampl(7), muse_bias(7), muse_create_sky(7), muse_dark(7), muse_exp_align(7), muse_exp_combine(7), muse_flat(7), muse_geometry(7), muse_illum(7), muse_lingain(7), muse_lsf(7), muse_qi_mask(7), muse_scibasic(7), muse_scipost(7), muse_scipost_apply_astrometry(7), muse_scipost_calibrate_flux(7), muse_scipost_combine_pixtables(7), muse_scipost_correct_dar(7), muse_scipost_correct_rv(7), muse_scipost_make_cube(7), muse_scipost_raman(7), muse_scipost_subtract_sky(7), muse_scipost_subtract_sky_simple(7), muse_standard(7), muse_twilight(7), muse_wavecal(7)

muse_astrometry 2.8.7

Peter Weilbacher <https://support.eso.org>

Please report any problems to https://support.eso.org. Alternatively, you may send a report to the ESO User Support Department <usd-help@eso.org>.

This file is part of the MUSE Instrument Pipeline Copyright (C) 2005, 2019 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 02111-1307 USA

2.8.7 muse_astrometry