[fitsbits] Re: FITS Format

[Louis Giglio]

BITSWAP is not a standard FITS keyword.  I suspect that the file
was written on a little-endian machine (probably a Windows or MS-DOS
box) running software that didn't want to bother swapping bytes into the
proper FITS big-endian format.  A file like this should have a
SIMPLE = 'F' keyword in the primary HDU, although it probably doesn't
(there is some commercial software that does not write legal FITS files).

What value does the BITSWAP keyword have?  If it's a logical type with a
value of 'T' (true) then you should probably try swapping bytes in the
data portion of each HDU.  Are you familiar with the software the
created the file?

Cheers,
Louis


In article <9g5i55$9mp$1 at canarie.caspur.it>, "Acrobat"
<l.azario at rm.unicatt.it> writes:

> Hello I have a problem to write a program in Visual Basic to read a
> fits file.  For the header section there are no problem but for the
> data there a problem.  In the file header  I find a card with the
> keyword : BITSWAP that it is not documented in any my documentation
> that I found in the web.  Any idea on this keyword ?
>
> Do you know a librarry that I can use with my Visual Basic program?
>
> Thank you
>
> Luigi Azario