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Draft of FITS standard revision 1.2 available for comment
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>From email@example.com Wed Apr 15 10:30:26 1998
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From: Richard White <email@example.com>
Subject: Draft of FITS standard revision 1.2 available for comment
To: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com,
Date: Wed, 15 Apr 1998 10:24:31 -0400 (EDT)
Cc: firstname.lastname@example.org (Richard White)
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PLEASE REDISTRIBUTE WIDELY
Call for comments on Revised FITS Standard
The NASA/Science Office of Standards and Tecnology (NOST) Draft Standard
100-1.2, Definition of the Flexible Image Transport System (FITS), is now
available for review and comment. This is a major revision to the previous version 1.1 of the FITS standard that was adopted in 1995. This Standard is being
developed by a NOST-sponsored Technical Panel.
FITS Technical Panel
Robert J. Hanisch, Chair STScI
Barry M Schlesinger, Secretary NASA/FITS Support Office
Allen Farris STScI
Eric W. Greisen NRAO
William D. Pence NASA/GSFC
Peter J. Teuben UMd
Randall W. Thompson STScI/CSC(formerly at GSFC/IUE)
Archibald Warnock A/WWW Enterprises
The purpose of distributing this Draft Revision to the NOST FITS Standard is to
provide for community review and comment. The Technical Panel will review and
respond to all comments. The Panel will either incorporate the substance of a
comment into the Standard, or it will instead provide the reasons for not doing
so and describe any revision to the Standard motivated by the comment. After
the panel has completed review of and responded to all comments, the final
version will be submitted to NOST for certification. Upon certification, the
final version number will be 2.0. It will then be submitted to IAU Commission 5
for formal acceptance as the IAU standard.
Copies of the standard are available in two ways: paper copies and access to
electronic copies via the WWW. Electronic copies are available formatted for
LaTeX, PostScript, gziped Postscript and html. The electronic versions are
posted on the FITS Support Office web site homepage at
Paper versions may be requested from the National Space Science Data Center
Coordinated Request and User Support Office (CRUSO) at
Coordinated Request User Support Office (CRUSO)
National Space Science Data Center
NASA Goddard Space Flight Center
Greenbelt, Maryland 20771, USA
Telephone: (301) 286-6695
FAX: (301) 286-1635
All comments should be mailed to the fitsbits exploder at
email@example.com, or posted to the newsgroup sci.astro.fits.
Dr. William Pence, a member of the technical panel,
will oversee the reading, discussion, and panel response to all comments.
There will be an approximately 3 month period for comments. All comments
should be submitted by July 15, 1998.
The development of the standard and its certification is supported by the FITS
Support Office in the Astrophysics Data Facility at NASA's Goddard Space
FITS Support Office
NASA/Goddard Space Flight Center
Greenbelt, MD 20771
List of Significant Changes Between Versions 1.1 and 1.2 (Draft) of the NOST
Section Description of Changes
3: Definitions have been added, deleted, or revised:
Added: ASCII NULL, DAT, Fraction, Heap, IAUFWG,
Mantissa, Primary HDU, Repeat count
Deleted: AIPS, CfA, ESO, NOAO, NRAO, STScI
Revised: Entry, Floating point, Indexed keyword
4.6: New section describing Physical Blocking. Incorporates some text
previously contained in Appendix B.
188.8.131.52: Explicitly states that null-valued keywords are allowed.
184.108.40.206: Keyword comment, if present, must be preceeded by a slash.
5.2: References to ANSI FORTRAN-77 have been removed and
replaced with explicit definitions of free format values.
5.2: Keyword values are restricted to be a single value
and not an array of values.
5.2.1: Fixed format character string values no longer need to be
padded with blanks to be at least 8 characters long.
(e.g., XTENSION= 'TABLE' is now a legal keyword record).
5.2.1: Previous requirement that reading the data values should
not require decoding any more than the first eight
characters of a character string value of a keyword has
5.2.2: Explicitly states that a logical value must consist
of a single `T' or `F' character, followed only by a
space or a slash character.
5.2.3: Explicitly states that an integer value must not contain
embedded spaces and is always interpreted as a signed
5.2.4: Explicitly states that a real floating point value must not
contain embedded spaces. The decimal point is not required,
so values like 12, and 1E30 are valid, but E30 is not.
5.2.5: Fixed format for complex integers is no longer defined.
Free format complex integer values must be enclosed in
parentheses separated by a comma, e.g. (14, -45).
5.2.6: Fixed format for complex reals is no longer defined.
Free format complex real values must be enclosed in
parentheses separated by a comma, e.g. (14.5, -4.5E+5).
220.127.116.11 Explicitly states that no other keywords may intervene between
the SIMPLE and last NAXISn keyword in the primary header.
The SIMPLE keyword must not appear in extension headers.
18.104.22.168 Explicitly states that no other keywords may intervene between
the XTENSION and last NAXISn keyword in an extension.
5.4.2 The description of the DATE and DATE-OBS keywords has been
modified in accordance with the new Y2000 FITS agreement.
6.3 Definition of IEEE floating point has been moved to appendix H.
8.1 Explicitly states that no other keywords may intervene between
the XTENSION and TFIELDS keywords in an ASCII table extension.
The TFORM format codes must be in upper case. Numeric values
in ASCII tables are always decimal, and never binary, octal,
hexadecimal, or other representation.
8.1.5 New discussion about selecting a format appropriate to the
data. References to ANSI FORTRAN-77 have been removed and
replaced with explicit definitions of how each format should
8.2 Definition of the image extension has been added.
8.3 Definition of binary table extension has been moved from
Appendix A into the standard itself. The TFORM format codes
must be in upper case.
8.3.4 Explicit definitions are given for the possible display formats.
Appendix A: (new) gives a formal syntax for keyword card images.
Appendix D: (new) discusses time scale issues related to the new
DATE-OBS keyword format.
Appendix H: (new) defines IEEE floating point formats
Types of keywords that are explicitly allowed in the new FITS standard
KEYWORD = / the value of this keyword is undefined
XTENSION= 'TABLE' / string can be less than 8 chars long
REALVAL = 14 / decimal point is not required for reals
COMPLEXI= (12, -45) / complex integer value
COMPLEXR= (12.5, 5.6E-3) / complex real value
DATE = '2000-01-01T11:45:59.999' / new date format
Types of keywords that are explicitly disallowed in the new FITS standard
KEYWORD = 3.1415 Value of Pi (no slash before comment)
KEYWORD = 1,2,3,4,5,8 / arrays of values are not allowed
LOGICAL = TRUE / logical values must be only T or F
INTVAL = 0777 / must not be interpreted as octal number
INTVAL = 124 56 / embedded spaces not allowed in integers
REALVAL = 1.34 E+11 / embedded spaces not allowed in reals
REALVAL = E20 / number preceeding the exponent is required
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