I've been trying to copy the FITS headers from one piddle to another,
but wfits seems to be mangling the header somehow.
In the code below, I know that rfits should give $im a hash with the
FITS header, but I wanted to be explicit in pulling out the header into
$im_hdr - the input is a data cube and the output is a smaller data cube
with NAXIS=3, NAXIS3=5:
---code---
my $im = rfits $file;
my $im_hdr = rfitshdr $file;
print "### BEFORE...\n";
print_hdr(%$im_hdr);
$$im_hdr{NAXIS3} = "5";
print "### CHANGED NAXIS3...\n";
print_hdr(%$im_hdr);
$output_image->sethdr($im_hdr);
print "AFTER...\n";
print_hdr(%$im_hdr);
wfits $output_image,$output_file;
sub print_hdr { use strict; my (%hash) = @_; foreach my $k (sort keys %hash) {
print "$k => $hash{$k}\n"; } }
---end code---
...but wfits then cautions with:
Use of uninitialized value in string eq at
/usr/lib/perl5/site_perl/5.8.8/Astro/FITS/Header.pm line 1426,
<AUTOLOAD_FILE> line 22.
...and in IRAF ds9 cannot display the resultant image, and reporting
back with:
imhead test.fits l+
test.fits[320,258,5][double]:
No bad pixels, min=0., max=0. (old)
Line storage mode, physdim [320,258,5], length of user area 243 s.u.
Created Tue 14:01:24 02-Oct-2007, Last modified Tue 14:01:24 02-Oct-2007
Pixel file "test.fits" [NO PIXEL FILE]
BUNIT = 'Data Value'
BSCALE = 1 / default scaling factor
BZERO = 32768 / offset data range to that of unsigned
short
EXTEND = T / FITS dataset may contain extensions
COMMENT FITS (Flexible Image Transport System) format is defined in
'Astronomy
COMMENT and Astrophysics', volume 376, page 359; bibcode:
2001A&A...376..359H
Note the [NO PIXEL FILE] comment seems to be the diagnostic of FITS file
not being read by IRAF.
If I remove the $$im_hdr{NAXIS3} = "5"; line then wfits gives me:
Warning: wfits corrected dimensions of FITS header at ./clean_dark_and_flats.pl
line 199
...with the same imhead result as before.
Finally, removing all attempts to adjust the header in $output_file
results in a working output file that can be displayed in IRAF, without
any of the headers.
Thanks for your time,
Matt
--
Matthew Kenworthy / Instrument Scientist / CAAO / Steward Observatory
Room N414 / 933 N. Cherry Ave / Tucson AZ 85721 / vox 520 626 6720
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