MTANHDR(1)

✨ MTANHDR ✨ (the mTANHdr manual page, bestie edition)

okay so bestie, welcome to mTANHdr 💖 this is a Montage tool and it's literally here to help you figure out if your header could have an equivalent distorted TAN projection. She's a little niche, she's a little powerful, and she is so much faster than the general-purpose girlie. let's get into it 🫶

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🌸 NAME 🌸

mTANHdr — determine if there would be an equivalent distorted TAN projection 👑

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🎀 SYNOPSIS 🎀

mTANHdr [-d] [-o order][-i maxiter][-t tolerance][-s statusfile]
orig.hdr new.hdr

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🦋 DESCRIPTION 🦋

So what she does is: she analyzes a template file and figures out if there would be an adequate equivalent distorted TAN projection, within a specified tolerance, and then she outputs the alternate header. periodt.

That header can be used in conjunction with mProjectPP to produce a TAN plane image ✨ and the way that this process is considerably faster than projecting with the general purpose tool mProject? iconic.

The output header is a FITS header template containing a TAN projection with polynomial focal plane distortions. (Link to an example output header)

mTANHdr is most suitable for projections which can be approximated by tangent-plane projections (TAN, SIN, ZEA, STG, ARC), and is also therefore not suited for images covering large portions of the sky. no cap, keep her in her lane 🙈

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💅 OPTIONS 💅

• -d — print additional debugging information to stdout. she's chatty, she's telling you everything 🗣️
• -o order — order of output header polynomial focal plane distortions (default = 4)
• -i maxiter — maximum number of iteration attempts to produce header (default = 50)
• -t tolerance — distortion tolerance value for acceptable output (default = 0.01)
• -s statusfile — output and errors are written to statusfile instead of stdout.

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🍓 ARGUMENTS 🍓

• orig.hdr — input FITS header
• new.hdr — path to output header to be created

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🌈 RESULT 🌈

[struct stat="OK", fwdxerr=fwdxerr, fwdyerr=fwdyerr, fwditer=iter,
revxerr=revxerr, revyerr=revyerr, reviter=reviter]

where fwdxerr and fwdyerr are the maximum errors along each axis found when projecting from the original image to the distorted header; revxerr and revyerr are the maximum errors along each axis found when projecting from the distorted header back to the original header; and fwditer and reviter are the number of iterations required in each direction to converge on a solution 💫

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💜 MESSAGES 💜

• OK — [struct stat="OK", fwdxerr=fwdxerr, fwdyerr=fwdyerr, fwditer=iter, revxerr=revxerr, revyerr=revyerr, reviter=reviter]
• ERROR — -i (iterations) argument
• ERROR — -o (order) argument
• ERROR — -t (tolerance) argument
• ERROR — Cannot open status file: statusfile
• ERROR — Cannot open output template file new.hdr
• ERROR — All points offscale in forward transform
• ERROR — All points offscale in reverse transform
• ERROR — Bad template: orig.hdr
• ERROR — Output wcsinit() failed.
• ERROR — Singular Matrix-1
• ERROR — Singular Matrix-2
• ERROR — Allocation failure in ivector()

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⭐ EXAMPLES ⭐

$ mTANHdr input/SIN_1.hdr alternate.hdr
       [struct stat="OK", fwdxerr=4.31068e-05, fwdyerr=4.42599e-05,
       fwditer=4, revxerr=1.22123e-05, revyerr=1.19694e-05, reviter=4]

The output header is a FITS header template containing a TAN projection with polynomial focal plane distortions: alternate.hdr 🎉

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💀 BUGS 💀

The drizzle algorithm has been implemented but has not been tested in this release. so like, she's there, she's just untested, be careful 🫠

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"] — windows line endings really said "not today" 😭

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 is safer to turn on the "level only" background matching (the -l flag in mBgModel).

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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 version 5, dated Dec 2016 — mwah, slay, go project something pretty ✨🎀🦋