---
name: "fors_pmos_extract"
section: "7"
platform: "linux"
package: "cpl-plugin-fors-doc"
version: "5.5.6+dfsg-4"
release: "Debian 11 (Bullseye)"
platforms: ["linux"]
url: "https://new.carta.tech/fors_pmos_extract"
---

# fors\_pmos\_extract(7)

Extraction of scientific spectra

## NAME

fors\_pmos\_extract - Extraction of scientific spectra

## SYNOPSIS

esorex **fors\_pmos\_extract** \[OPTIONS\] FILE.sof

## DESCRIPTION

This recipe is used to reduce scientific spectra using the extraction mask and the products created by the recipe fors\_mpol\_calib. The spectra are bias subtracted, flat fielded (if a normalised flat field is specified) and remapped eliminating the optical distortions. The wavelength calibration can be optionally upgraded using a number of sky lines: if no sky lines catalog of wavelengths is specified, an internal one is used instead.

If the alignment to the sky lines is performed, the input dispersion coefficients table is upgraded and saved to disk, and a new CCD wavelengths map is created.

This recipe accepts both FORS1 and FORS2 frames. A grism table (typically depending on the instrument mode, and in particular on the grism used) may also be specified: this table contains a default recipe parameter setting to control the way spectra are extracted for a specific instrument mode, as it is used for automatic run of the pipeline on Paranal and in Garching. If this table is specified, it will modify the default recipe parameter setting, with the exception of those parameters which have been explicitly modifyed on the command line. If a grism table is not specified, the input recipe parameters values will always be read from the command line, or from an esorex configuration file if present, or from their generic default values (that are rarely meaningful).

Either a scientific or a standard star exposure can be specified in input.

The acronym SCI on products should be read STD in case of standard stars observations.

Input files:

  DO category:               Type:       Explanation:         Required:\
   SCIENCE\_PMOS                  Raw         Scientific exposure     Y\
   or STANDARD\_PMOS              Raw         Standard star exposure  Y\
   MASTER\_BIAS                   Calib       Master bias             Y\
   GRISM\_TABLE                   Calib       Grism table             .

  MASTER\_SKYLINECAT             Calib       Sky lines catalog       .

  MASTER\_NORM\_FLAT\_PMOS         Calib       Normalised flat field   .

  DISP\_COEFF\_PMOS               Calib       Inverse dispersion      Y\
   CURV\_COEFF\_PMOS               Calib       Spectral curvature      Y\
   SLIT\_LOCATION\_PMOS            Calib       Slits positions table   Y\
   RETARDER\_WAVEPLATE\_CHROMATISM Calib       Chromatism correction   .

Output files:

  DO category:               Data type:  Explanation:\
   REDUCED\_SCI\_PMOS             FITS image  Extracted scientific spectra\
   REDUCED\_SKY\_SCI\_PMOS         FITS image  Extracted sky spectra\
   REDUCED\_ERROR\_SCI\_PMOS       FITS image  Errors on extracted spectra\
   REDUCED\_SCI\_X\_PMOS           FITS image  X Stokes parameter (and L)\
   REDUCED\_ERROR\_X\_PMOS         FITS image  Error on X Stokes parameter\
   REDUCED\_NUL\_X\_PMOS           FITS image  Null parameter for X\
   REDUCED\_POL\_ANGLE\_PMOS       FITS image  Direction of linear polarization\
   REDUCED\_POL\_ANGLE\_ERROR\_PMOS FITS image  Error on polarization direction\
   UNMAPPED\_SCI\_PMOS            FITS image  Sky subtracted scientific spectra\
   MAPPED\_SCI\_PMOS              FITS image  Rectified scientific spectra\
   MAPPED\_ALL\_SCI\_PMOS          FITS image  Rectified science spectra with sky\
   MAPPED\_SKY\_SCI\_PMOS          FITS image  Rectified sky spectra\
   UNMAPPED\_SKY\_SCI\_PMOS        FITS image  Sky on CCD\
   GLOBAL\_SKY\_SPECTRUM\_PMOS     FITS table  Global sky spectrum\
   OBJECT\_TABLE\_SCI\_PMOS        FITS table  Positions of detected objects\
   OBJECT\_TABLE\_POL\_SCI\_PMOS    FITS table  Positions of real objects

  Only if the sky-alignment of the wavelength solution is requested:\
   DISP\_COEFF\_SCI\_PMOS          FITS table  Upgraded dispersion coefficients\
   WAVELENGTH\_MAP\_SCI\_PMOS      FITS image  Upgraded wavelength map

## OPTIONS

- **--dispersion** *\<float\>*

  Resampling step (Angstrom/pixel) (float; default: 0.0). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.dispersion** \[default = *0.0*\].

- **--skyalign** *\<int\>*

  Polynomial order for sky lines alignment, or -1 to avoid alignment (int; default: 0). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.skyalign** \[default = *0*\].

- **--wcolumn** *\<str\>*

  Name of sky line catalog table column with wavelengths (str; default: ´WLEN´). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.wcolumn** \[default = *WLEN*\].

- **--startwavelength** *\<float\>*

  Start wavelength in spectral extraction (float; default: 0.0). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.startwavelength** \[default = *0.0*\].

- **--endwavelength** *\<float\>*

  End wavelength in spectral extraction (float; default: 0.0). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.endwavelength** \[default = *0.0*\].

- **--flux** *\<bool\>*

  Apply flux conservation (bool; default: True). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.flux** \[default = *True*\].

- **--flatfield** *\<bool\>*

  Apply flat field (bool; default: False). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.flatfield** \[default = *False*\].

- **--skyglobal** *\<bool\>*

  Subtract global sky spectrum from CCD (bool; default: False). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.skyglobal** \[default = *False*\].

- **--skymedian** *\<bool\>*

  Sky subtraction from extracted slit spectra (bool; default: False). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.skymedian** \[default = *False*\].

- **--skylocal** *\<bool\>*

  Sky subtraction from CCD slit spectra (bool; default: True). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.skylocal** \[default = *True*\].

- **--cosmics** *\<bool\>*

  Eliminate cosmic rays hits (only if global sky subtraction is also requested) (bool; default: False). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.cosmics** \[default = *False*\].

- **--slit\_margin** *\<int\>*

  Number of pixels to exclude at each slit in object detection and extraction (int; default: 3). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.slit\_margin** \[default = *3*\].

- **--ext\_radius** *\<int\>*

  Maximum extraction radius for detected objects (pixel) (int; default: 6). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.ext\_radius** \[default = *6*\].

- **--cont\_radius** *\<int\>*

  Minimum distance at which two objects of equal luminosity do not contaminate each other (pixel) (int; default: 0). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.cont\_radius** \[default = *0*\].

- **--ext\_mode** *\<int\>*

  Object extraction method: 0 = aperture, 1 = Horne optimal extraction (int; default: 1). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.ext\_mode** \[default = *1*\].

- **--time\_normalise** *\<bool\>*

  Normalise output spectra by the exposure time (bool; default: True). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.time\_normalise** \[default = *True*\].

- **--chromatism** *\<bool\>*

  Chromatism correction to polarization angles (bool; default: True). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.chromatism** \[default = *True*\].

- **--check** *\<bool\>*

  Create intermediate products (bool; default: False). The full name of this option for the EsoRex configuration file is **fors.fors\_pmos\_extract.check** \[default = *False*\].

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.

## SEE ALSO

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

-

  **ftp://ftp.eso.org/pub/dfs/pipelines/fors/fors-pipeline-manual-4.9.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 fors pipeline are [*fors\_align\_sky*(7)](/fors_align_sky/7.md), [*fors\_align\_sky\_lss*(7)](/fors_align_sky_lss/7.md), [*fors\_bias*(7)](/fors_bias/7.md), [*fors\_calib*(7)](/fors_calib/7.md), [*fors\_config*(7)](/fors_config/7.md), [*fors\_dark*(7)](/fors_dark/7.md), [*fors\_detect\_objects*(7)](/fors_detect_objects/7.md), [*fors\_detect\_spectra*(7)](/fors_detect_spectra/7.md), [*fors\_extract*(7)](/fors_extract/7.md), [*fors\_extract\_objects*(7)](/fors_extract_objects/7.md), [*fors\_extract\_slits*(7)](/fors_extract_slits/7.md), [*fors\_flatfield*(7)](/fors_flatfield/7.md), [*fors\_img\_science*(7)](/fors_img_science/7.md), [*fors\_img\_screen\_flat*(7)](/fors_img_screen_flat/7.md), [*fors\_img\_sky\_flat*(7)](/fors_img_sky_flat/7.md), [*fors\_normalise\_flat*(7)](/fors_normalise_flat/7.md), [*fors\_photometry*(7)](/fors_photometry/7.md), [*fors\_pmos\_calib*(7)](/fors_pmos_calib/7.md), [*fors\_pmos\_science*(7)](/fors_pmos_science/7.md), [*fors\_remove\_bias*(7)](/fors_remove_bias/7.md), [*fors\_resample*(7)](/fors_resample/7.md), [*fors\_science*(7)](/fors_science/7.md), [*fors\_spec\_mflat*(7)](/fors_spec_mflat/7.md), [*fors\_subtract\_sky*(7)](/fors_subtract_sky/7.md), [*fors\_subtract\_sky\_lss*(7)](/fors_subtract_sky_lss/7.md), [*fors\_sumflux*(7)](/fors_sumflux/7.md), [*fors\_trace\_flat*(7)](/fors_trace_flat/7.md), [*fors\_wave\_calib*(7)](/fors_wave_calib/7.md), [*fors\_wave\_calib\_lss*(7)](/fors_wave_calib_lss/7.md), [*fors\_zeropoint*(7)](/fors_zeropoint/7.md)

## VERSION

fors\_pmos\_extract 5.5.6

## AUTHOR

Carlo Izzo \<usd-help@eso.org\>

## BUG REPORTS

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

## LICENSE

This file is currently part of the FORS Instrument Pipeline Copyright (C) 2002-2010 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  02110-1301  USA
