I am looking for FITS files where BITPIX = 32 and NAXIS = 2
Don Wells
dwells at nrao.edu
Tue Jul 14 12:05:04 EDT 1998
>>>>> "Juan" == Juan Jose Garcia Adeva <jgadeva at jet.uk> writes:
Juan> Hello, I am using the FITS format in a project, but I only
Juan> need to support files with BITPIX = 32 and NAXIS = 2. .. I
Juan> cannot find any example in
Juan> http://www.cv.nrao.edu/fits/data/samples. ..
Try your code on this 262_KB file:
http://www.cv.nrao.edu/fits/data/tests/incunabula/m87-32.fits
Examine the two text files m87-32.list and m87-32.vf in the same
directory. Note that ORIGIN='KPNO' and DATE='13/09/79': this is the
oldest FITS file with BITPIX=32. The 'vf' file is the output of a FITS
file verifier when reading this file. It asserts that the '/' in the
keyword 'IPPS-B/P' is illegal, however this file is readable by modern
software (Cotton's FITSview code displays the file properly). The
'IPPS' refers to KPNO's Interactive Picture Processing System, the
predecessor of IRAF and 'B/P' is bits per pixel; the IPPS executed on
a CDC 60-bit computer, and floating point pixels were carried in half
words, probably with 20-bit mantissas but I can no longer remember
that detail. The number system of this FITS test file was specially
contrived: BSCALE=1.00000E-06 was used in order to make the
significant bits be spread across the second and third bytes to expose
byte-flip bugs. Furthermore, the file asserts that BLANK=-2147483648,
so this header is sensitive to differences in implementations of number
conversion routines, the situation discussed by John Davis and Bill
Pence in the unsigned-integer thread in the past few days.
-Don
--
Donald C. Wells Associate Scientist dwells at nrao.edu
http://www.cv.nrao.edu/~dwells
National Radio Astronomy Observatory +1-804-296-0277
520 Edgemont Road, Charlottesville, Virginia 22903-2475 USA
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