MUSE_ASTROMETRY(7)

📦
version 2.8.7 · 2 versions
, in debian bookworm, ubuntu noble

💖 NAME 💖

muse_astrometry — compute an astrometric solution ✨ (it's the MUSE recipes manual, section 7, bestie 🫶)

🌸 SYNOPSIS 🌸

esorex muse_astrometry [OPTIONS] FILE.sof

✨ DESCRIPTION ✨

okay so here's the whole vibe 💅 This recipe merges the pixel tables from all the IFUs, applies the correction for differential atmospheric refraction (when that's necessary, i.e. when you need it), and — if you handed it the right input data — it will optionally do flux calibration and telluric correction too. Then it resamples the data from all exposures into a datacube 🦋

Then it takes that cube and detects objects in it, matches those objects to their reference positions, and from that computes a two-dimensional WCS solution. Iconic. 👑

There are two pattern matching algorithms implemented, and you pick between them by choosing a positive or a zero value of faccuracy:

  1. Method one (positive 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. Then remove the remaining unidentified objects.
  2. Method two (faccuracy 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. ate, no notes. 💅

The main output is the ASTROMETRY_WCS file — a bare FITS header containing the world coordinate solution, that's the main character here 👑 The secondary product is DATACUBE_ASTROMETRY; you don't need it for further processing, but it's great for verification and debugging (vibe check 🌈). It contains the reconstructed cube plus 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 that's used to detect and centroid the stars (as well as its variance).

🎀 OPTIONS 🎀

  • --centroid <str> — Which centroiding method to use for objects in the field of view. "gaussian" and "moffat" use 2D fits to derive the centroid, and "box" is a simple centroid in a square box. Type str, default moffat. 🧚
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.centroid [default = moffat].
  • --detsigma <float> — Source detection sigma level to use. If this is negative, values between its absolute value and 1.0 are tested with a stepsize of 0.1, to find an optimal solution. Type float, default 1.5. 🔥
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.detsigma [default = 1.5].
  • --radius <float> — Initial radius in pixels for pattern matching identification in the astrometric field. Type float, default 3.0. ✨
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.radius [default = 3.0].
  • --faccuracy <float> — Factor of initial accuracy relative to the mean positional accuracy of the measured positions, used for pattern matching. If this is set to zero, use the quadruples based method (that's method two up above, iykyk 👀). Type float, default 0.0.
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.faccuracy [default = 0.0].
  • --niter <int> — Number of iterations of the astrometric fit. Type int, default 2. 🦋
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.niter [default = 2].
  • --rejsigma <float> — Rejection sigma level of the astrometric fit. Type float, default 3.0. 💜
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.rejsigma [default = 3.0].
  • --rotcenter <str> — Center of rotation of the instrument, given as two comma-separated floating point values in pixels. Type 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].
  • --lambdamin <float> — Cut off the data below this wavelength after loading the pixel table(s). Type float, default 4000.0. ⭐
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.lambdamin [default = 4000.0].
  • --lambdamax <float> — Cut off the data above this wavelength after loading the pixel table(s). Type float, default 10000.0. ⭐
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.lambdamax [default = 10000.0].
  • --lambdaref <float> — 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. Type float, default 7000.0. 👑
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.lambdaref [default = 7000.0].
  • --darcheck <str> — Carry out a check of the theoretical DAR correction using source centroiding. If "correct" it will also apply an empirical correction. Type str, default none. 🌈
    • The full name of this option for the EsoRex configuration file is muse.muse_astrometry.darcheck [default = none].
🫶 btw bestie, you can make a configuration file containing these options, along with suitable default values. Go look at the details provided by the esorex --help command, it's giving instructions.

🔭 SEE ALSO 🔭

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) — the whole friend group fr fr 🫂💖

⭐ VERSION ⭐

muse_astrometry 2.8.7

👑 AUTHOR 👑

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

🩹 BUG REPORTS 🩹

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>. (no gatekeeping here, they wanna hear it 😭)

📜 LICENSE 📜

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

and that's the whole page bestie — brought to you by muse_astrometry, version 2.8.7, straight out of the muse recipes manual (section 7). slay, go compute that WCS 💅✨🦋

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