wcstools(1)

✨ wcstools — the manual page, but make it cute ✨

okay bestie, sit down, hydrate, and let me tell you about wcstools 💖 this is the WCSTools manual (that's the manual name, in wcstools(1), General Commands Manual — iykyk), and it's literally just a whole girlboss collection of programs to access image world coordinate systems and catalogs. no cap. let's go 🦋

🎀 Setting an Image World Coordinate System 🎀

the "give your image a sense of self" era. main character energy only.

• imwcs — automatically finds stars in a FITS or IRAF image, matches them to HST Guide, USNO A, B, UCAC or UJ Stars, or others, computes the relation between sky coordinates and image coordinates, and writes it in the image header. (this one came after U of Iowa's SETWCS, periodt.)
• delwcs — deletes the WCS keywords from an image. and the tea ☕: if both EPOCH and EQUINOX are present, then EQUINOX gets deleted too. it's giving "no, you too."

🌈 Using an Image World Coordinate System 🌈

now that your image knows where it is in the universe (literally), here's how to talk to it.

• imcat — lists catalog sources that should be found in the area of the sky covered by a specific image. vibe check: does the sky agree with your picture? 🔥
• imsize — prints the center and size of an image using the WCS keywords in the header.
• imstar — finds and lists the n brightest stars in an IRAF or FITS image, with their sky coordinates if there's WCS info in the image header. bestie is doing the most and honestly? slay ✨
• sky2xy — prints image pixel coordinates for given sky coordinates, either on the command line or in a list file.
• xy2sky — prints sky coordinates for given image pixel coordinates, either on the command line or in a list file. yes it's the reverse of the one above, they're a matched set 🫶

🍓 Catalog Utility Programs 🍓

for when you want to go shopping in the sky's inventory.

• scat — searches the HST GSC, USNO-A2.0, or another catalog, given a region on the sky.
• skycoor — converts between J2000, B1950, and Galactic coordinates, from the command line or a file. three coordinate systems, one little icon 👑

💅 Image Utility Programs 💅

the supporting cast, but make it iconic.

• addpix — adds a constant value(s) to specified pixel(s).
• edhead — edits the header of a FITS file, or the user parameters of an IRAF image file, using the text editor specified by the EDITOR environment variable. (so it's literally whatever editor you picked, no judgment 🌸)
• gethead — returns values for the keyword(s) specified after the filename.
• getpix — returns the value(s) of specified pixel(s).
• i2f — reads a two-dimensional IRAF image file and writes a FITS image file.
• imhead — prints a FITS or IRAF header.
• imrot — rotates and/or reflects FITS or IRAF image files.
• setpix — sets specified pixel(s) to specified value(s).
• sethead — sets header parameters in FITS or IRAF images.

💖 Author 💖

Jessica Mink, SAO (jmink@cfa.harvard.edu) — the actual legend behind all of this, we stan 🎀

and that's the whole page bestie, no notes. this version of wcstools(1) is from WCSTools, dated 6 July 2001, and honestly the way it's still out here serving world coordinate systems twenty-plus years later? iconic behavior. bye bestie, go match some stars ⭐🦋✨