[gnuastro-devel] [task #14315] Propagate all FITS header keywords into output FITS files

[Lee Kelvin]

URL:
  <http://savannah.gnu.org/task/?14315>

                 Summary: Propagate all FITS header keywords into output FITS
files
                 Project: GNU Astronomy Utilities
            Submitted by: leeskelvin
            Submitted on: Fri 20 Jan 2017 06:00:34 PM GMT
         Should Start On: Fri 20 Jan 2017 12:00:00 AM GMT
   Should be Finished on: Fri 20 Jan 2017 12:00:00 AM GMT
                Category: All Gnuastro
                Priority: 5 - Normal
              Item Group: Enhancement
                  Status: None
                 Privacy: Public
        Percent Complete: 0%
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
                  Effort: 0.00

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Details:

When performing an image rotation using ImageWarp, or an image crop using
ImageCrop, all user-supplied FITS header keywords should be propagated through
to the resultant output file.

Many contemporary astronomy surveys embed a lot of valuable information in the
headers of FITS images, such as date of observation, wavelength, telescope,
airmass, etc. If is often desirable to crop or manipulate large survey FITS
files to produce smaller postage stamps around objects of interest. However,
when doing this with ImageCrop or ImageWarp, all of this extra information is
lost.

By way of example, I attach a very simple FITS file ('input.fits') to this
post. It is a 3x3 image with the bare minimum FITS header. I have added to the
header the new user-supplied keyword 'TEST'. I then run the following two
commands:


$ astimgcrop --section=1:1,1:1 input.fits
$ astimgwarp --rotate=90 input.fits


The first command creates an even smaller 1x1 pixel cutout from the 3x3 image,
whilst the second simply rotates the image through 90 degrees. This produces
the two output files 'input_crop.fits' and 'input_rotated.fits'.

As can be seen, the header keyword 'TEST' has been removed from both output
files.

I am unsure if this behaviour impacts more than one GNU Astro software
packages, as these are the two I have tested most extensively so far. However,
as this behaviour impacts more than one package, I have marked it as 'All
Gnuastro' for the time being.

Regards, 
Lee Kelvin




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File Attachments:


-------------------------------------------------------
Date: Fri 20 Jan 2017 06:00:34 PM GMT  Name: input.fits  Size: 6kB   By:
leeskelvin

<http://savannah.gnu.org/task/download.php?file_id=39521>
-------------------------------------------------------
Date: Fri 20 Jan 2017 06:00:34 PM GMT  Name: input_crop.fits  Size: 6kB   By:
leeskelvin

<http://savannah.gnu.org/task/download.php?file_id=39522>
-------------------------------------------------------
Date: Fri 20 Jan 2017 06:00:34 PM GMT  Name: input_rotated.fits  Size: 8kB  
By: leeskelvin

<http://savannah.gnu.org/task/download.php?file_id=39523>

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