FITS Time WCS Standard

Arnold Rots, SAO/CXC, 2014-09-25

This standard has been developed by Arnold H. Rots (SAO), Peter S. Bunclark (deceased, IoA), Mark R. Calabretta (ATNF), Steven L. Allen (UCO), Richard N. Manchester (ATNF), William T. Thompson (Adnet Systems, NASA GSFC).
It was approved by the IAU FITS Working Group on 2014-06-09 and accepted by A&A on 2014-09-25.

Version 1.1 is the version accepted by A&A:
Postscript or PDF format.
It is available in Letter size in Postscript or PDF format.

Version History

Version 1.03 was submitted to A&A. It is identical in content to version 1.02, with redlining and obsolete comments in the LaTeX file removed and updates to abstract and keywords:
Postscript or PDF format.
It is available in Letter size in Postscript or PDF format.

The comments received during the IAU FWG vote have been incorporated into version 1.02:
Postscript or PDF format.
It is available in Letter size in Postscript or PDF format.

The comments received during the comment period had been incorporated into version 1.01:
Postscript or PDF format.
It is available in Letter size in Postscript or PDF format.

The current version, 1.0, is intended for formal review; it is identical to version 0.982.
It is available in A4 size in Postscript or PDF format.
It is available in Letter size in Postscript or PDF format.

The eighth draft version was 0.982.
That draft is still available as Postscript (PS/Letter) or PDF (PDF/Letter).
This was now considered the final draft submitted for community comments before the formal review. The changes since version 0.981 are shown in red.
Comments on Version 0.981 were sent by Mark Calabretta, Bill Pence, and Lucio Chiappetti. Accompanying Version 0.982 is a response to these comments.
We provide as a sample file a shortened Chandra event list that was modifed to comply with the proposed standard, similar to Example 5.

The seventh version is 0.981.
That draft is still available as Postscript or PDF.
The changes since version 0.98 are shown in red.

The sixth version is 0.98.
That draft is still available as Postscript or PDF.
The changes since version 0.93 are shown in red.

The fifth version is 0.93.
That draft is still available as Postscript or PDF.
This was considered a final draft submitted for community comments before the formal review. The most important changes since Version 0.90:

• Extended discussion of Besselian and Julian epochs
• Allow [M]JDREF to be split into integer and fractional part
• Provide for time-related axes (temporal) Phase, Frequency, and Timelag
• Added a fifth example
• Resolved loose threads, especially in Appendix A

The third version is 0.90.
That draft is still available as Postscript or PDF.
This version is close to complete on the major issues.
Editorial comments in Appendix A are printed in red. These highlight details that the authors still need to work out. Appendix B just highlights a few changes and will eventually be deleted.

The second version is 0.73.
That draft is still available as Postscript or PDF.
Although more complete than Version 0.71, this version still needs a little more polishing and there are still some remaining issues that are yet to be resolved.
Editorial comments are printed in red.

The first public version was 0.71.
That draft is still available as Postscript or PDF.

Additional resources:

• The current FITS Standard
• The FITS WCS documentation page
• The FITS Y2k agreement
• The USNO Timescales page
• The Chandra time tutorial
• The IVOA STC standard

Last modified: 2014-09-25