FITS(1)

📦
version 0.24 · 5 versions
, in epel 10, epel 9, nixos 26.05, nixpkgs unstable, ubuntu resolute, ubuntu stonking

✨ FITS(1) — the manual page, but make it cute ✨

okay bestie, welcome to FITS(1) from the User Commands section, aka the glow-up era of Fits 💅

🌸 NAME 🌸

Fits — view and manipulate FITS headers 🦋

⭐ SYNOPSIS ⭐

astfits [OPTION...] ASTRdata

💖 DESCRIPTION 💖

Fits is part of GNU Astronomy Utilities 0.24. no cap, this is the tool. Fits lets you view and manipulate (add, delete, or modify) FITS extensions (or HDUs) and FITS header keywords within one extension. it's giving ✨cosmic filing cabinet✨ and honestly? obsessed.

want more tea? run any of these commands. the second one is the whole lore drop — it has the very comprehensive explanation of Fits's invocation: expected input(s), output(s), and a full description of all the options. 🫶

all options and their values:

$ astfits -P

inputs/outputs and options:

$ info astfits

full section in the manual/book:

$ info Fits

full Gnuastro manual/book:

$ info gnuastro

if you couldn't find your answer in the manual, you can get direct help from experienced Gnuastro users and developers. for more info, just run:

$ info help-gnuastro

🎀 FITS OPTIONS 🎀

🧚 INPUT 🧚

  • --arguments=STR — plain-text file with command-line arguments. like, hand it a whole lil txt of args, iykyk.
  • -h, --hdu=STR/INT — extension name or number of input data. name it or number it, either way bestie.

🍓 OUTPUT 🍓

  • -K, --keepinputdir — keep the input directory for automatic output. don't move it, it lives there 🥺
  • --outfitsnocommit — no Git commit in 0-th HDU of output FITS.
  • --outfitsnoconfig — no metadata in 0-th HDU of output FITS.
  • --outfitsnodate — no 'DATE' in 0-th HDU of output FITS.
  • --outfitsnoversions — no versions in 0-th HDU of output FITS.
  • --outhdu=STR — HDU/extension in output for --copykeys.
  • -o, --output=STR — output file name (not for keywords). so if you're doing keyword stuff, this one's not the move.
  • -O, --colinfoinstdout — column info/metadata when printing to stdout.
  • --tableformat=STR — table fmt: 'fits-ascii', 'fits-binary', 'txt'.
  • -T, --type=STR — type of output: e.g., int16, float32, etc...

🔥 HDU (EXTENSION) INFORMATION 🔥

  • --datasum — calculate HDU's datasum and print in stdout.
  • --datasum-encoded — 16 character string encoding of '--datasum'.
  • --hasimagehdu — file has at least one image HDU.
  • --hastablehdu — file has at least one table HDU.
  • --listallhdus — list all HDUs within the file.
  • --listimagehdus — list all image HDUs within the file.
  • --listtablehdus — list all table HDUs within the file.
  • -n, --numhdus — print number of HDUs in the given FITS file.
  • --pixelareaarcsec2 — pixel area in arc-seconds squared.
  • --pixelscale — return the pixel-scale of the HDU's WCS.
  • --skycoverage — image coverage in the WCS coordinates.

🦋 HDU (EXTENSION) MANIPULATION 🦋

  • -C, --copy=STR/INT — copy extension to output file.
  • -k, --cut=STR/INT — copy extension to output and remove from input. girl is moving out, taking her stuff 💀
  • --primaryimghdu — copy/cut image HDUs to primary/zero-th HDU.
  • -R, --remove=STR/INT — remove extension from input file.

👑 KEYWORDS (IN ONE HDU) 👑

  • -a, --asis=STR — write value as-is (may corrupt FITS file). ⚠️ bestie this one is a little unhinged, it can genuinely wreck your FITS file, so know what you're doing.
fr fr, <red>may corrupt FITS file</red> is not a vibe check, it's a warning. proceed with main character caution 💅
  • --copykeys=INT:INT/STR,STR — range/names of keywords to copy in output.
  • -c, --comment=STR — add COMMENT keyword, any length is ok.
  • -d, --delete=STR — delete a keyword from the header.
  • -H, --history=STR — add HISTORY keyword, any length is ok.
  • -l, --keyvalue=STR[,STR,...] — only print the value of requested keyword(s).
  • --printkeynames — print all keyword names.
  • -p, --printallkeys — print all keywords in the selected HDU.
  • -r, --rename=STR,STR — rename keyword, keeping value and comments. glow-up but keep the personality ✨
  • -s, --datetosec=STR — FITS date to sec from 1970/01/01T00:00:00.
  • -t, --date — set the DATE keyword to the current time.
  • -u, --update=STR,STR — update a keyword value or comments.
  • -v, --verify — verify the CHECKSUM and DATASUM keywords.
  • --wcscoordsys=STR — convert WCS coordinate system.
  • --wcsdistortion=STR — convert WCS distortion to another type.
  • -w, --write=STR — write a keyword (with value, comments and units).

🌈 META-IMAGE CREATION 🌈

  • --edgesampling=INT — number of extra samplings in pixel sides.
  • --pixelareaonwcs — image where pixels show their area in sky (WCS).

💜 OPERATING MODES 💜

  • -?, --help — give this help list.
  • --checkconfig — list all config files and variables read.
  • --cite — BibTeX citation for this program. cite your sources, queen 📚
  • --config=STR — read configuration file STR immediately.
  • --config-prefix=STR — custom prefix of option names config files.
  • --lastconfig — do not parse any more configuration files.
  • --minmapsize=INT — min. bytes to avoid RAM automatically.
  • --onlyversion=STR — only run if the program version is STR.
  • -P, --printparams — print parameter values to be used and abort.
  • --quietmmap — don't print mmap'd file's name and size.
  • -q, --quiet — only report errors, remain quiet about steps.
  • -Q, --quitonerror — quit if there is an error on any action.
  • -S, --setdirconf — set default values for this directory and abort.
  • --usage — give a short usage message.
  • -U, --setusrconf — set default values for this user and abort.
  • -V, --version — print program version.

mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. just so we're clear bestie 🫶

GNU Astronomy Utilities home page: http://www.gnu.org/software/gnuastro/

😭 REPORTING BUGS 😭

report bugs to bug-gnuastro@gnu.org. not me being the one to tell you, but they genuinely wanna know 🐛

Copyright © 2015-2025 Free Software Foundation, Inc. License GPLv3+: GNU General public license version 3 or later.

This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. (fr fr, no warranty, it said it not me 💀)

Written/developed by Mohammad Akhlaghi 👑

🦋 SEE ALSO 🦋

the full documentation for Fits is maintained as a Texinfo manual. if the info and Fits programs are properly installed at your site, the command

info Fits

should give you access to the complete manual.

and that's the whole page bestie, slay 💅✨

GNU Astronomy Utilities 0.24 · November 2025 · FITS(1) — you've reached the end of the manual, go touch some grass and then come back and read your headers 🌸🫶
📦 where this page comes from