Giga photo of the Milky Way in 108199x81503 resolution or another story “xyz Enough for everyone”

    A couple of days ago there was news that astronomers of the European Southern Observatory stitched a mosaic of the center of our galaxy (the Milky Way) with a resolution of 108199x81503 in the IR range (in IR there is much less light scattering from interstellar gas and dust - there are much more stars visible).

    Unfortunately, they posted the result only in the form of an online browser and a .psb file , 24 GB in size, which can be opened only with Photoshop, while the photoshop itself refused to export it to any other format except again psb, tiff (of course it’s unsuccessful, there’s a size file cannot exceed 2 / 4GB) and RAW. And I wanted something from which it would be convenient to cut an interesting piece on wallpaper ...

    Looking ahead, I will immediately show the results:

    1920x1200 2560x16002880x1800

    1920x1200 2560x1600 2880x1800

    Full size image (total 33.4Gb): thepiratebay
    Here is laid as a raw-file, or several versions of jpeg-s, from wallpaper-s and 10% (10820x8150) to the maximum (65500x65500 centered at the center of the galaxy , 5.8GB, 100% scale, non-fit parts are trimmed) + 65500x65500 compressed to 170MB for stress testing software .

    Dramatic details omitted, just facts about JPEG and ImageMagick

    It is possible to process such large pictures only with the x64 version of ImageMagick, and it is extremely advisable to use the Q8 version rather than Q16 (with increased accuracy of the internal representation): Q8 eats up about 45GB of memory during operation, and Q16 - ~ 72GB, which had a very bad effect on speed.

    JPEG historically cannot have a size above 65535x65535, but in many libraries the limit is 65500x65500 (at one time it really seemed an unattainable size ...).

    In order to keep the saving in JPEG, you need to disable the optimization of Huffman tables (apparently there is an overflow of code frequency counters): -define jpeg: optimize-coding = false

    We also managed to save the full-size image in PNG, but nothing could open it + size at all it turned out 22GB, so I had to stop at JPEG.

    Final teams get such
    convert -size 108199x81503 -depth 8 -scale 50% -quality 95 -define jpeg:optimize-coding=false eso1242a.jpg
    convert -size 108199x81503 -depth 8 -crop "65500x65500+22500-0!" -gravity North  -quality 95 -define jpeg:optimize-coding=false eso1242a_sq.jpg

    Operating time - about 30 minutes for 1 operation.

    Here I realized that 32GB of memory is not enough for everyone :-)

    Links & credits

    Credit: ESO / VVV Consortium
    Released under the Creative Commons Attribution 3.0 Unported license
    Acknowledgment: Ignacio Toledo, Martin Kornmesser
    www.eso. org / public / images / eso1242a / zoomable

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