MPIX2COORD(1)

🦋 NAME 🦋

okay bestie, meet mPix2Coord (that's the Montage manual, page MPIX2COORD(1), if you're keeping track) — it outputs the sky location corresponding to a pixel coordinate. yes, it's literally a pixel-to-sky translator and it's iconic for it 💅

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✨ SYNOPSIS ✨

mPix2Coord [-d] template.hdr ixpix jypix

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🌸 DESCRIPTION 🌸

So the way this works: you hand it an image FITS header template and a pixel (x,y) coordinate, and it hands you back the corresponding sky location. that's the whole vibe. sky location out, pixel in, no cap 🫶

lowkey important tea: newer mExamine can do the same thing and more — but only for real image files. so if you're working with a template, this is your girl.

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💖 OPTIONS 💖

• -d — print out additional debugging information. extra yapping, but make it useful 🔥

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🎀 ARGUMENTS 🎀

• template.hdr — ASCII header template describing the image (either a FITS image, or a JPEG file created from the FITS file). it's giving "the blueprint" ✨
• ixpix — X coordinate (pixel location) on image.
• jypix — Y coordinate (pixel location) on image.

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🌈 RESULT 🌈

[struct stat="OK", lon=ra, lat=dec]

where ra, dec are the sky coordinates that correspond to the input pixel. yes bestie, lon=ra and lat=dec — that's the whole point of the exercise 👑

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⭐ MESSAGES ⭐

• OK — [struct stat="OK", lon=ra, lat=dec]
• ERROR — Bad template: template.hdr
• ERROR — Output wcsinit() failed.

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🧚 EXAMPLES 🧚

say you wanna find out what the coordinates are at the 100,130 pixel on an image defined by template.hdr. watch:

$ mPix2Coord template.hdr 100 130
       [struct stat="OK", lon=0.027777, lat=0.036110]

ate. no crumbs. 😭💖

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💀 BUGS 💀

bestie, listen up, this part is important.

The drizzle algorithm has been implemented but has not been tested in this release. so like... it exists. that's all we can say for sure 🙈

If a header template contains carriage returns (i.e., created/modified on a Windows machine), the cfitsio library will be unable to read it properly, resulting in the error: [struct stat="ERROR", status=207, msg="illegal character in keyword"]. literally the Windows line-ending jumpscare 🪟💀

It is best for the background correction algorithms if the area described in the header template completely encloses all of the input images in their entirety. If parts of input images are "chopped off" by the header template, the background correction will be affected. We recommend you use an expanded header for the reprojection and background modeling steps, returning to the originally desired header size for the final coaddition. The default background matching assumes that there are no non-linear background variations in the individual images (and therefore in the overlap differences). If there is any uncertainty in this regard, it's safer to turn on the "level only" background matching (the -l flag in mBgModel). k that one's a mouthful but fr fr, don't skip it 🌸

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👑 COPYRIGHT 👑

2001-2015 California Institute of Technology, Pasadena, California

If your research uses Montage, please include the following acknowledgement: "This research made use of Montage. It is funded by the National Science Foundation under Grant Number ACI-1440620, and was previously funded by the National Aeronautics and Space Administration's Earth Science Technology Office, Computation Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technology."

The Montage distribution includes an adaptation of the MOPEX algorithm developed at the Spitzer Science Center.

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and that's the whole page, bestie 🫶 this was Montage 5, dated Dec 2016 — go find your sky coordinates, you absolute main character 🌟💜