Subject: ARN provision SIMPLE = T ?

From: abs9d at galen.med.Virginia.EDU (Amy B. Sprenkle)
Date: Tue, 31 Jan 1995 04:19:40 GMT

Hi,

	I ran across some  "FITS" files whose header started

	SIMPLE = T /ARN provision

	yet the file does not appear to follow much if any of
the standard fits format.   What is the story here?

	Thanks Amy

---

From: bschlesinger at nssdca.gsfc.nasa.gov (Barry M. Schlesinger)
Date: 31 Jan 1995 13:43 EDT

In article <D395Cs.3r8 at murdoch.acc.Virginia.EDU>, abs9d at galen.med.Virginia.EDU (Amy B. Sprenkle) writes...
>the standard fits format.   What is the story here?

Without knowing more about the files, only general comments are 
possible.  

The signature of FITS is 
SIMPLE  =                   T
at the start of the file, with the = in column 9 and T in column 30.  
To be a legitimate FITS file, the material following that first line 
must follow the FITS rules, and the FITS signature should not be used 
if the rest of the files does not do so.  If the line is exactly as 
above, it does not follow the FITS syntax, but it still should not be 
called FITS.
				Barry Schlesinger
				NSSDC/NOST FITS Support Office

---

From: abs9d at galen.med.Virginia.EDU (Amy B. Sprenkle)
Date: Wed, 1 Feb 1995 15:24:50 GMT

Thanks Barry,
	I have looked at these files in detail, and they are
very similar to standard FITS (80 byte records followed by data)
except they allow record block size modification in the header
and do not use any of the required keywords.  This is
unfortunate because there appears to be little memory savings
from their modification, and no enhancements.  They should have
just left them in fits format.  Apparently IMDISP reads these
files OK..?

	Do you know the author of IMDISP? 

	Oh,.. almost forgot, these files have SIMPLE and T in
the correct place, but the equals sign is in 28, not 9 byte
location.

	Thanks  Amy