VISIR_UTIL_UNDISTORT(7)

💖 VISIR_UTIL_UNDISTORT(7) 💖

okay bestie, welcome to the visir recipes glow-up corner of the manual pages ✨ this one is visir_util_undistort, and she is literally here to fix the distortion in your spectral data. no cap.

---

✨ NAME ✨

visir_util_undistort — correct the distortion in spectral data 🦋

---

🎀 SYNOPSIS 🎀

esorex visir_util_undistort [OPTIONS] FILE.sof

---

🌸 DESCRIPTION 🌸

so the files you list in your Set Of Frames (aka the sof-file, you know her) have to be tagged like this:

• VISIR-chopnod-corrected-file.fits → CHOPNOD_CORRECTED

and optionally, if you're feeling generous, you can hand over a bad pixel map too:

• VISIR-bpm-file.fits → STATIC_MASK

the product(s) you get back will have a FITS card ´HIERARCH ESO PRO CATG´ with a value of: UNDISTORTED 👑

lowkey important: the recipe default values for the transformation are only valid for spectral data taken in Low resolution mode. like, that's the whole vibe check. don't come for me if you use defaults in another mode, okay? 😭

---

💅 OPTIONS 💅

• --bkgcorrect <bool> — Cho-nod correct the data (bool; default: True). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.bkgcorrect [default = True]. ✨
• --xl <int> — coordinate in spatial direction. together with yl it defines the lower point of a rectangle containing only skylines for the wavelength shift detection (int; default: 117). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.xl [default = 117]. 🎀
• --yl <int> — coordinate in wavelength direction. see xl (int; default: 110). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.yl [default = 110]. 💖
• --xh <int> — coordinate in spatial direction. together with yl it defines the higher point of a rectangle containing only skylines for the wavelength shift detection (int; default: 125). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.xh [default = 125]. 🌈
• --yh <int> — coordinate in wavelength direction. see xh (int; default: 150). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.yh [default = 150]. 🦋
• --slit_skew <float> — distortion correction: Skew of slit (degrees) (clockwise) (float; default: 0.52). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.phi [default = 0.52]. 🫶
• --spectrum_skew <float> — distortion correction: LMR Skew of spectrum (degrees) (counter-clockwise). not used in High Resolution (float; default: 1.73). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.ksi [default = 1.73]. 🌸
• --vert_arc <float> — distortion correction: LR Detector vertical curvature (pixel). reduced by a factor 4 in MR. not used in HR A-side. increased by a factor 115/52 in HR B-side (float; default: -0.8). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.eps [default = -0.8]. 🔥
• --hori_arc <float> — distortion correction: LMR Detector horizontal curvature (pixel). increased by a factor 1.5 in HR A-side. reduced by a factor 2 in HR B-side (float; default: 0.0). the full name of this option for the EsoRex configuration file is visir.visir_util_undistort.delta [default = 0.0]. ⭐

---

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 visir pipeline can be downloaded as a PDF file using the following URL:

ftp://ftp.eso.org/pub/dfs/pipelines/visir/visir-pipeline-manual-1.4.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 visir pipeline are — and yes, we're listing every single one, because the group chat deserves the full roster 💜:

• visir_img_dark(7)
• visir_img_ff(7)
• visir_img_reduce(7)
• visir_img_trans(7)
• visir_old_img_combine(7)
• visir_old_img_phot(7)
• visir_old_spc_obs(7)
• visir_old_spc_obs_ech(7)
• visir_old_spc_phot(7)
• visir_old_spc_phot_ech(7)
• visir_old_spc_wcal(7)
• visir_old_spc_wcal_ech(7)
• visir_old_util_destripe(7)
• visir_spc_reduce(7)
• visir_util_apply_calib(7)
• visir_util_clip(7)
• visir_util_convert_weight(7)
• visir_util_detect_shift(7)
• visir_util_img_std_cat(7)
• visir_util_join(7)
• visir_util_qc(7)
• visir_util_repack(7)
• visir_util_run_swarp(7)
• visir_util_spc_std_cat(7)
• visir_util_spc_txt2fits(7)

---

💜 VERSION 💜

visir_util_undistort 4.4.2

---

👑 AUTHOR 👑

Lars Lundin <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>.

---

🎀 LICENSE 🎀

this file is part of the VISIR Instrument Pipeline Copyright (C) 2011 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 💖 this was visir_util_undistort, version 4.4.2, from the visir recipes manual section 7 — go forth and undistort, you absolute icon ✨🦋🎀