FITSPNG(1)

✨ FITSPNG(1) ✨

okay bestie, gather round, because this is the User Commands glow-up of fitspng and it's lowkey iconic 💅

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🎀 NAME 🎀

fitspng — the FITS to PNG converter, and yes she does exactly what it says on the tin, no cap.

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🌸 SYNOPSIS 🌸

fitspng [options] file(s)

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🦋 DESCRIPTION 🦋

So fitspng is a utility, and her whole job is converting images in the astronomical FITS format into PNG format. That's it, that's the assignment, and she eats every time 💖

FITS format is a general purpose astronomical format which stores measurements of physical quantities. FITS images represent an angular distribution of captured photon events, or intensity of light — basically the receipts of what the sky was doing ✨

fitspng provides visualisation of FITS images by converting them to PNG format.

The detailed description can be found on the page: https://integral.physics.muni.cz/fitspng — go read it, iykyk 👑

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💅 OPTIONS 💅

okay so here's the whole menu, and no we are NOT skipping any of them, every single one matters:

• -f [asinh|snlike|sqr|tanh|photo] — scale output intensities by the specified profile. pick your vibe: asinh, snlike, sqr, tanh, or photo 🌈
• -r q,v — relative pre-scaling mode. here q and v represent the quantiles of a background (sky) and the relative sensitivity respectively 🫶
• -l B,s — absolute pre-scaling mode. B and s are directly used for scaling of the output frame, no chill, just numbers 💀
• -S c — the colour saturation gets multiplied by the given ratio c. this one's for colour FITS only, so don't come for her if you're working in grey 🙈
• -n Y,w — when used, it switches on a mode which emulates human's night vision. it is useful only for colour FITS 🌙 (scotopic girlies rise)
• -s s — shrink image: scale down the size of image by the specified factor s, as a (non-zero) positive integer number. if the s factor is greater than one, any output pixel is constructed as the arithmetic mean of s*s input pixels. so yes, it's doing actual math, it's giving ✨averaging✨
• -o — specify an output file name, valid only if a single file is passed.

if this switch is omitted, the output filename is determined by modification of input filenames: suffixes, like *.fits, are replaced by *.png, and the directory path is removed. this approach leaves the original data untouched, and the results are stored in the current working directory. queen behaviour, honestly 👑

• -B [8|16] — 8 bites per pixel of colour (grey) depth of output. this is the default. 16 bites per pixel of colour (grey) depth of output.

heads up bestie: with 16 there is frequently a problem with additional rendering. most utilities don't work with this colour depth correctly. on the other side, 16 bit per pixel images have the photometric content saved. so it's a trade-off, choose wisely 💀

• -v — print additional info during processing. she's chatty, we love that 💬
• --help — show summary of options.
• --version — display software version.

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🍓 EXAMPLES 🍓

convert an image from FITS to PNG:

$ fitspng -o grey.png grey.fits

emulate human's night vision:

$ fitspng -n 1e6,1 -o scotopic.png  colour.fits

emulate classical photography sensitivity function (density curve):

$ fitspng -f photo -o photo.png colour.fits

create semi-grey image:

$ fitspng -S 0.2 -o reduced.png colour.fits

select the specified band from colour FITS (with help of FITS file name extension):

$ fitspng -o green.png "colour.fits[1]"

create thumbnails:

$ fitspng -s 10 *.fits

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💜 AUTHOR 💜

Filip Hroch <hroch@physics.muni.cz> — absolute legend, thank you for your service 🫡💖

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⭐ SEE ALSO ⭐

• rawtran(1)
• [1] https://integral.physics.muni.cz/fitspng
• [2] http://www.libpng.org/pub/png/
• [3] https://integral.physics.muni.cz/rawtran
• [4] https://munipack.physics.muni.cz/

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and that's the whole page, bestie!! 🎀 this one comes to you from Fitspng, January 2022 — go make something pretty with it, mwah 💋✨🦋