Registered Extension Type Names

Extension type names must be unique; a particular type name may refer to only one structure. In order to avoid duplication, all extension type names must be registered with the IAU FITS Working Group, even if the extension type is being used by only a single organization internally. To register a FITS extension name, contact either the FITS Support Office at fits@nssdca.gsfc.nasa.gov or the chair of the IAUFWG at dwells@nrao.edu. Provide a short description and justification with the request for registration. Reserve extension type names when their use is planned, even though details of the structure have not been worked out.

Table 5.1 lists the FITS extension type names and their registered status with the IAUFWG at the time this Guide is being written. Also included in the table are the organization with current responsibility for the extension and its development and, when available, a reference describing the extension. Table 5.2 explains the status codes in Table 5.1.

Table 5.1: Reserved Extension Type Names

Type Name	Status	Reference	Sponsor	Comments
'A3DTABLE'	L	NRAO(1990)	NRAO	Prototype binary table design
				supported in AIPS, superseded by
				BINTABLE, which supports
				all A3DTABLE features.
'BINTABLE'	S	Cotton,	IAU	Binary Tables. Available at
		Tody, and		FITS Archives in files
		Pence(1995)		documents/standards/bintable*
				for 1995-Feb-06 Note: only main
				document, excluding appendixes.
'COMPRESS'	R	Warnock	GSFC	Suggested name by
		et. al.	A/WWW	A. Warnock
		(1990)		Preliminary proposal
'DUMP '	R	none	none	Suggested name for binary dumps.
				No full proposal submitted.
'FILEMARK'	R	none	NRAO	Intended for structure to
				represent equivalent of
				tape mark on other media.
				No full proposal submitted.
'IMAGE '	S	Ponz,	IAU	Image extension, contains
		Thompson,		an array of one or
		and Muñoz		more dimensions.
		(1994)
'IUEIMAGE'	L	Muñoz	IUE	Prototype matrix
		(1989)		extension used for archiving
				IUE products, superseded by IMAGE.
'TABLE '	S	Harten	IAU	ASCII tables.
		et al.
		(1988)
'VGROUP '	R	Jennings	GSFC	Reserved for possible use in
		et al.		supporting analog of HDF group
		(1996)		structures under FITS.
				Current proposal does not use
				separate extension type.

Table 5.2: Possible Status Levels for FITS Extensions

Status	Description
S	Standard FITS extension type accepted by the IAUFWG and
	endorsed by the IAU.
P	Proposal for FITS extension type accepted by regional
	FITS committees but not yet by the IAUFWG.
D	Draft proposal, to be discussed in regional FITS committees and by
	community.
R	Reserved FITS extension type name for which a full draft proposal
	has not yet been submitted.
L	Local FITS extension type in use only by a particular group.

The up-to-date official listing of extensions registered with the IAUFWG is available on-line from the FITS Support Office at http://ssdoo.gsfc.nasa.gov/astro/fits/xtension.html or ftp://nssdc.gsfc.nasa.gov/pub/fits/xtension.lis. This listing is revised as information is received from the IAUFWG about the registration of new type names or progress of a particular extension type through the approval process.