sky2xy(1)

✨ sky2xy — the glow-up ✨

okay bestie, imagine you've got a FITS or IRAF image and a bunch of sky coordinates and you're like "where tf do these even land on my pixels" — that's literally what sky2xy is for 💅 it's pronounced sky-to-X-Y (iconic name, no notes), and it's a lil utility from the WCSTools manual, section 1 (General Commands Manual).

🌸 NAME 🌸

sky2xy — compute X Y from RA Dec using WCS in FITS and IRAF image files 🫶

🎀 SYNOPSIS 🎀

sky2xy [-vbjg] file.fts ra1 dec1 ... ran decn

or, the group-chat-coded version:

sky2xy [-vbjg] file.fts @listfile

🦋 DESCRIPTION 🦋

so. sky2xy is a utility for getting the image coordinates of a set of world coordinates in a FITS or IRAF image. it's giving translator, but make it astronomy ✨

the World Coordinate System (WCS) info sitting in the image header describes, in a standard way, the relationship between sky coordinates and image pixels. sky2xy uses that info to transform image right ascension and declination sky coordinate pairs into image coordinate (X,Y) pairs. slay.

one thing though — the program prints the coordinates in the same system as is given in the image header. no cap. but bestie, future versions will allow transformations to B1950/FK4, J2000/FK5, ecliptic or galactic coordinates 👀 and input and output files in the Starbase format will eventually be allowed too. manifesting 🕯️

💖 OPTIONS 💖

• -b — B1950 (FK4) input 🩷
• -e — Ecliptic longitude and latitude input 🌞
• -g — Galactic longitude and latitude input 🌌
• -j — J2000 (FK5) input ⭐
• -g — Galactic longitude and latitude input 🌌 (yes it's listed twice in the original, and yes we're keeping it twice, that's the whole point of this exercise bestie)
• -v — more descriptive output, i.e. she's giving detail 💬
• -z — use AIPS classic projections instead of WCSLIB 🔄

👀 SEE ALSO 👀

xy2sky() — the reverse girlypop, go say hi 💞

👑 AUTHOR 👑

Jessica Mink, SAO (jmink@cfa.harvard.edu) — queen behavior, we stan 💜

and that's the whole page, fr fr. this version is from 6 July 2001, brought to you by WCSTools — so when you're out here turning RA/Dec into X/Y, just know you're standing on iconic, slightly-ancient shoulders 🌈✨ bye bestie, go plot something gorgeous 🎀