Hello Derek,
sorry for not giving a working example, my code would not have made
things clearer :) But your example is a good example !
I do not think the problem is in the extension reading. If you look at
the header of your test.fits, you can see that the keyword NAXIS is
equal to 0 and there is no KW NAXIS1 and NAXIS2, whereas if you only
write the first extension, with wfits($bsub,'test.fits');, then you have
NAXIS = 2
NAXIS1 = 3
NAXIS2 = 4
which is what is expected.
The fact is, test.fits with the two extensions does contain the 3×4
image, it can be seen with ds9, but the header is wrong.
In my case, I read an existing fits file, process it, and save the
results in another file, and I want to propagate the huge input primary
header. The resulting header is the same as your test.fits, and I lose
all the input KW.
The problem is the writing of the primary header by wfits in the case
of several extensions. Is there any solution ?
Thank you in advance,
Best regards.
Le 15/07/2014 20:42, Derek Lamb a écrit :
Hello Frédéric,
Without a minimal working example, I made my own, but if you have a better
example it would be good to see it!
pdl> $bsub = sequence(3,4);
pdl> $FST = xvals(20);
pdl> $bsub->fhdr; #initialize an empty Astro::FITS::Header, let wfits correct it
pdl> $FST->fhdr;
pdl> wfits([$bsub,$FST],'test.fits');
pdl> ^Z
[2]+ Stopped pdl
$ more test.fits
#I see the primary header and then two extension headers which are correct
$ fg
pdl> $bsub_read = rfits('test.fits[1]'); #try to read them in one at a time
Unexpected end of FITS file at …PDL/IO/FITS.pm line 412.
##########
So it seems like there is a problem with the extension READING in PDL::IO::FITS.
Forcing a read of the primary extension seems to be OK:
pdl> $primary = rfits('test.fits[0]')
pdl> p keys %$primary
SIMPLE BITPIX NAXIS EXTEND COMMENT HDUNAME END
cheers,
Derek
On Jul 15, 2014, at 6:51 AM, Frédéric Royer <[email protected]> wrote:
Hello,
I am trying to write Fits files with 2 extensions.
When using:
wfits([$bsub,$FST],$skysubfits);
the header of the primary extension $bsub is not propagated and the output file
has a simplistic primary header,
whereas if I only write the first extension using
wfits($bsub,$skysubfits);
the output file has the correct header.
Is there a way to propagate the header when writing multi extension FITS files
with wfits ?
Thank you in advance
Best regards.
--
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GEPI / CNRS UMR 8111
Observatoire de Paris Tel: +33 1 45 07 78 44
92195 MEUDON cedex Fax: +33 1 45 07 78 78
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| \_/|_)_>(/_| \/(_| |_(_)|| (/_ |--- G E P I
de Paris |
ROYER Frederic
GEPI / CNRS UMR 8111
Observatoire de Paris Tel: +33 1 45 07 78 44
92190 MEUDON Fax: +33 1 45 07 78 78
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