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From: bschlesinger@nssdca.gsfc.nasa.gov (Barry Schlesinger)
Newsgroups: comp.graphics,sci.astro,sci.space
Subject: Fundamental FITS Information
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Date: 8 Nov 90 19:39:02 GMT
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This information is posted in response to requests for where general 
FITS information can be found.

The best references are the following three papers:

Wells, Greisen, and Harten, 1981, "FITS: a flexible image transport 
system", Astronomy and Astrophysics Supplements, v. 44, p. 363.

Grosbo\"l et al., 1988, "Generalized extensions and blocking factors 
for FITS", Astron. Astrophys. Suppl., 88,359.

Harten et al., 1988, "The FITS tables extension", Astron. Astrophys. 
Suppl., 88,365.

The titles of these papers show that FITS is not exclusively for the 
transport of digital images but can transport a wider variety of 
structures.

An additional paper, immediately following the 1981 paper cited above 
discussed "groups" format.  In practice, this format is used only to 
transfer and store radio interferometry results.  It is not widely 
used or understood elsewhere.

Originally, as discussed in the first FITS paper, the data matrix 
could contain only integers.  By international agreement, it now may 
contain IEEE-754 single and double precision floating point numbers.  
If a data matrix is composed of floating point numbers, then the
BITPIX keyword in the preceding header has a negatrive value (-32 for 
single and -64 for double precision).

The FITS Handbook is not yet available; the first sections, covering 
the Introduction, FITS history, and FITS fundamentals are expected to 
be available later this year.

We have not yet collected contributed software.  Probably, this office
will have information on software that the originators are willing to
make publicly available before the office itself has software to
distribute. 

					Barry Schlesinger
					NSDSSO FITS Support Office