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VIMOS_IMA_BIAS(7) vimos recipes VIMOS_IMA_BIAS(7)


vimos_ima_bias - Bias combination for imaging


esorex vimos_ima_bias [OPTIONS] FILE.sof


vimos_ima_bias -- VIMOS bias combine recipe.

Combine a list of bias frames into a mean bias frame. Optionally compare the output frame to a reference bias frame

The program accepts the following files in the SOF:

Tag Description

BIAS A list of raw bias images REFERENCE_BIAS Optional reference bias frame If no reference bias frame is made available, then no comparison will be done. This means there will be no output difference image or stats table.


--combtype <str>
Combination algorithm (str; default: ´median´). The full name of this option for the EsoRex configuration file is vimos.vimos_ima_bias.combtype [default = median].
--xrej <bool>
True if using extra rejection cycle (bool; default: True). The full name of this option for the EsoRex configuration file is vimos.vimos_ima_bias.xrej [default = True].
--thresh <float>
Rejection threshold in sigma above background (float; default: 5.0). The full name of this option for the EsoRex configuration file is vimos.vimos_ima_bias.thresh [default = 5.0].
--ncells <int>
Number of cells for diff image stats (int; default: 64). The full name of this option for the EsoRex configuration file is vimos.vimos_ima_bias.ncells [default = 64].
--prettynames <bool>
Use pretty output file names? (bool; default: False). The full name of this option for the EsoRex configuration file is vimos.vimos_ima_bias.prettynames [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.


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

An overview over the existing ESO pipelines can be found on the web page

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 for further information.

The other recipes of the vimos pipeline are vimos_ima_dark(7), vimos_ima_det_noise(7), vimos_ima_fringe(7), vimos_ima_science(7), vimos_ima_standard(7), vimos_ima_twilight_flat(7), vmbias(7), vmdark(7), vmdet(7), vmifucalib(7), vmifucombine(7), vmifucombinecube(7), vmifuscience(7), vmifustandard(7), vmmoscalib(7), vmmosscience(7), vmspphot(7)


vimos_ima_bias 4.1.1


Jim Lewis <>


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


This file is part of the VIMOS Instrument Pipeline Copyright (C) 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

4.1.1 vimos_ima_bias