[daip] FITS images and BITPIX

[Bill Cotton]

Lorant,

   The sign on BITPIX is very important, +32 means the pixel values
are 32 bit scaled integers; -32 means they are IEEE floating point,
possibly scaled values.  FITS2jpeg is based on cfitsio so should
handle any legitimate FITS image.

-Bill

Lorant Sjouwerman writes:
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 > Eric, Bill,
 > 
 > I write out FITS images using FITAB. I want to make thumbnails
 > in gif or jpg (eg using "FITS2jpeg") - something that shows up
 > standard in a web browser.
 > 
 > I tried "convert" but it blanks all pixels. It turns out that
 > the image FITS header has "BITPIX -32", ie negative 32. This
 > seems to be the upsetting statement, as when I edit it to 32,
 > "convert" does a better job (I see the image)
 > 
 > I have two main questions :
 > 
 > 1) Can I set BITPIX to be positive before writing out
 > 
 > 2) Does "FITS2jpeg" handle this better than "convert"
 >     (Bill's package doesn't seem to be installed at the AOC)
 > 
 > I have hundreds of images so doing it by hand is out of the
 > question. Also I plan to do this using "system" in AIPS and
 > thus like to avoid fooling around with "sed -e s/.." etc
 > 
 > Thanks a bunch
 > 
 > 
 > Regards,
 > 
 > Loránt Sjouwerman - Scientific Services - lsjouwerman at nrao.edu
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