FITS is used world-wide in astronomy, and thus a NASA FITS standard is not the final word. Recognizing the value-added of the NOST FITS Technical Panel's work, however, the community has taken the NASA standard as both a practical working document and has officially endorsed it through regional and international organizations. There are three regional FITS committees: the North American FITS Committee, which is convened under the auspices of the Working Group on Astronomical Software of the American Astronomical Society, the European FITS Committee, and the Japanese FITS Committee. Changes to the FITS standard are voted on in these committees and then forwarded for review to the FITS Working Group of the International Astronomical Union. The IAU FWG is the final voice of approval for revisions to the standard.
The NOST Technical Panel worked hard to resolve all discrepancies between the various FITS papers and to clarify all potentially ambiguous text. Nevertheless, some areas of the document may still be unclear to some readers or may be subject to misinterpretation. It is left to future Technical Panels to continue the effort to refine and clarify the document. These Technical Panels will also need to incorporate the results of future FITS negotiations into the document, such as the anticipated World Coordinate Systems (WCS) agreements (available at http://www.cv.nrao.edu/fits/documents/wcs/).
The NOST 100-2.0 document was approved by all three of the regional FITS Committees, without dissent, during 1999 and, in a vote taken on 12 October 2000, the IAU FITS Working Group adopted the following resolution, without dissent:
The IAU FITS Working [IAU-FWG] Group adopts the "Definition of the Flexible Image Transport System (FITS)'' [NOST 100-2.0] as the official version of the FITS standards, superseding Astron. Astrophys. Suppl. 44, 363-370 (1981) and the other FITS papers listed in Sect. 2 of NOST 100-2.0, with these interpretations/modifications of its text:
- 1.
- Use of the word "deprecated'' in the first paragraph of Sect. 7 "Random Groups Structure'' is understood to mean that binary table extensions should be used in new astronomical application areas instead of the random groups format where either is appropriate and where there is no historical precedent for random groups. Existing applications of the random groups structure (almost exclusively interferometry) may continue to use random groups as needed indefinitely;
- 2.
- It is noted that the following sentence in B.2, "The size implied by the TDIMn keyword will equal the element count specified in the TFORMn keyword.'' is not valid in the case of variable length array columns. This sentence should be replaced with wording similar to the following: "The total number of elements in the array equals the product of the dimensions specified in the TDIMn keyword. This size must be equal to the repeat count on the TFORMn keyword, or, in the case of columns which have a "P'' TFORMn datatype, equal to the array length specified in the variable length array descriptor (see Appendix B.1). In the special case where the variable length array descriptor has a size of zero, then the TDIMn keyword is not applicable.''
Acknowledgements
The authors acknowledge the support of NOST, in particular, Don Sawyer, for spearheading the standardization effort. The National Space Science Data Center and Astrophysics Data Facility at NASA Goddard Space Flight Center have sponsored the FITS Support Office, staffed for many years by Barry Schlesinger and overseen by Richard A. White. The community owes immeasurable thanks to Don Wells, National Radio Astronomy Observatory, for his tireless efforts in building consensus in the FITS community and his leadership of the IAU FITS Working Group. Preben Grosbøl, European Southern Observatory, preceded Don in this role and has also provided leadership within the European community. Bill Pence (HEASARC, NASA Goddard Space Flight Center) has written the most complete FITS I/O software package and this is widely used in the community. Peter Bunclark (IoA, Cambridge) and Arnold Rots (SAO) led the development of the DATExxxx keywords for year 2000 compatibility. The authors of the original FITS papers, Don Wells, Eric Greisen, Ron Harten, Preben Grosbøl, Daniel Ponz, Randy Thompson, José Muñoz, Bill Cotton, Doug Tody, and Bill Pence, deserve great credit for their ground-breaking work and ingenuity in adapting FITS to accommodate new data structures.The members of the regional FITS committees (as of October 1999) and the IAU FITS Working Group are listed below.
North American FITS Committee Peter Teuben, Chair U. Maryland Steve Allen Lick Observatory Daniel Durand HIA/CADC Allen Farris STScI Eric Greisen NRAO Arne Henden USNO Robert Kibrick Lick Observatory William Lupton Keck Observatory Eric Mandel CfA Robert Narron IPAC William Pence NASA GSFC Jeffrey Percival U. Wisconsin Arnold Rots CfA Skip Schaller Steward Observatory Barry Schlesinger Raytheon ITSS Randall Thompson Computer Sciences Corp. Doug Tody NOAO Stephen Walton Cal. State U. Northridge Archibald Warnock A/WWW Enterprises Don Wells NRAO Robert Hanisch STScI (ex officio)
European FITS Committee Preben Grosbøl, Chair ESO Peter Bunclark IoA, Cambridge Anatoly Piskunov IoA, Russian Acad. Sci. Ernst Raimond NFRA Patrick Wallace RAL
Japanese FITS Committee Shiro Nishimura, Chair NAOJ Osamu Kanamitsu Fukuoka U. Yasuhiro Murata ISAS Eiji Nishihara NAOJ Toshiyuki Sasaki NAOJ Shigeomi Yoshida U. Tokyo
IAU FITS Working Group Don Wells, Chair USA Bill Cotton USA John Glaspey USA Eric Greisen USA Preben Grosbøl Germany (ESO) Robert Hanisch USA Don Jennings USA Osamu Kanamitsu Japan Francois Ochsenbein France William Pence USA Bruce Peterson Australia Anatoly Piskunov Russia Ernst Raimond The Netherlands Peter Teuben USA Doug Tody USA Pat Wallace UK Wayne Warren USA
Definition of the Flexible Image Transport System (FITS)
March 29, 1999
Standard
NOST 100-2.0
NASA/Science Office of Standards and Technology
Code 633.2
NASA Goddard Space Flight Center
Greenbelt, MD 20771
USA
Copyright ESO 2001