FORS_SUBTRACT_SKY(7)

✨ fors_subtract_sky ✨

okay bestie, gather round, because this is the fors_subtract_sky page and it's lowkey iconic 💅

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🌈 NAME 🌈

fors_subtract_sky — subtract sky from scientific spectra 🧚

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🎀 SYNOPSIS 🎀

esorex fors_subtract_sky [OPTIONS] FILE.sof

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💖 DESCRIPTION 💖

so basically, this recipe subtracts the sky emission from unrebinned slit spectra. how? by robust fitting along the CCD columns within each spectrum — meaning it fits the emission and deliberately excludes the signal from possible point-like objects in the slit (that's the "robust" part, she's not naive). 🫶

⚠️ fr fr, listen up: this method does NOT work if extended objects are in the slit — it really destroys the object spectra. Not being dramatic. That's the manpage talking. And it is not applicable to LSS data. 😭

The input scientific frames are produced by the recipes fors_remove_bias and fors_flatfield. ✨

Also — and this is important — this recipe cannot be applied to LSS or long-slit-like data (that's MOS/MXU with all slits at the same offset). And nope, there is no automatic recipe available for this. You're on your own, bestie. 🙈

Please refer to the FORS Pipeline User's Manual for more details. 📖

In the table below, the MXU acronym can alternatively be read as MOS, and SCI as STD. (iykyk)

📥 Input files

• SCIENCE_UNBIAS_MXU or SCIENCE_UNFLAT_MXU or STANDARD_UNBIAS_MXU or STANDARD_UNFLAT_MXU — Type: Calib — Frame with sky lines — Required: Y ✅
• CURV_COEFF_MXU — Type: Calib — Spectral curvature — Required: Y ✅
• SLIT_LOCATION_MXU — Type: Calib — Slit location on CCD — Required: Y ✅
• GRISM_TABLE — Type: Calib — Grism table — Required: . (so, optional vibes)

📤 Output files

• UNMAPPED_SCI_MXU or UNMAPPED_STD_MXU — Data type: FITS image — Sky subtracted scientific frame 🌟
• UNMAPPED_SKY_SCI_MXU or UNMAPPED_SKY_STD_MXU — Data type: FITS image — Subtracted sky frame 🌙

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✨ OPTIONS ✨

• --dispersion <float> — Expected spectral dispersion, in Angstrom/pixel (float; default: 0.0). The full name of this option for the EsoRex configuration file is fors.fors_subtract_sky.dispersion [default = 0.0]. 🔥
• --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_subtract_sky.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_subtract_sky.endwavelength [default = 0.0]. 🌸
• --cosmics <bool> — Eliminate cosmic ray hits (bool; default: False). The full name of this option for the EsoRex configuration file is fors.fors_subtract_sky.cosmics [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.

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👀 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 — and yes, we're listing all of them, no skipping, periodt:

• fors_align_sky(7)
• fors_align_sky_lss(7)
• fors_bias(7)
• fors_calib(7)
• fors_config(7)
• fors_dark(7)
• fors_detect_objects(7)
• fors_detect_spectra(7)
• fors_extract(7)
• fors_extract_objects(7)
• fors_extract_slits(7)
• fors_flatfield(7)
• fors_img_science(7)
• fors_img_screen_flat(7)
• fors_img_sky_flat(7)
• fors_normalise_flat(7)
• fors_photometry(7)
• fors_pmos_calib(7)
• fors_pmos_extract(7)
• fors_pmos_science(7)
• fors_remove_bias(7)
• fors_resample(7)
• fors_science(7)
• fors_spec_mflat(7)
• fors_subtract_sky_lss(7)
• fors_sumflux(7)
• fors_trace_flat(7)
• fors_wave_calib(7)
• fors_wave_calib_lss(7)
• fors_zeropoint(7)

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🦋 VERSION 🦋

fors_subtract_sky 5.5.7

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👑 AUTHOR 👑

Carlo Izzo <usd-help@eso.org> 💌

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💀 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>. (same inbox, two ways to slide in, we love efficiency 🫶)

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📜 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.

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and that's the whole page bestie, no cap — fors_subtract_sky version 5.5.7, straight from the fors recipes manual, mwah 💋