[fitsbits] The CONTINUE and HIERARCH Conventions Public Comment Periods

[William Pence]

First, a reminder that the Public Comment Period on the CONTINUE keyword
convention will be closing soon.

Second, the Public Comment Period on the the ESO HIERARCH keyword
convention is now open.

Detailed information about both of these conventions is available for
public review and comment from the FITS registry web page at

              http://fits.gsfc.nasa.gov/fits_registry.html

Comments about these conventions may be posted here on the FITSBITS mail
exploder or the sci.astro.fits newsgroup.  Minor typographical issues
may be sent directly to the authors of the convention.

Bill Pence
(on behalf of the IAU FITS Working Group)

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Brief description of the HIERARCH keyword convention:

Under the HIERARCH keyword convention, as originally defined by ESO,
bytes 10 through 80 of the HIERARCH keyword record contain a series of
ASCII strings, or tokens, that serve to hierarchically classify the
keyword, followed by an equals sign ('=') which is in turn followed by
the keyword value field. An optional comment field may follow the value
field. The value and comment fields conform to the rules for free-format
keywords, as defined in the FITS Standard document.

The following is an example of this convention:

HIERARCH ESO INS OPTI-3 ID = 'ESO#427' / Optical element identifier

The hierarchical keywords can be mapped into variable names by
concatenating the hierarchical tokens together, separating them with the
full stop character. For example, the hierarchical keyword shown above
corresponds to the variable name ESO.INS.OPTI-3.ID.

This ESO convention can be generalized to support keyword names longer
than 8 characters, or which contain ASCII characters that would
otherwise be prohibited. Some examples are shown below:

HIERARCH LongKeyword = 47.5 / keyword has > 8 characters and mixed case
HIERARCH XTE$TEMP = 98.6 / This keyword name contains the '$' character

-- 
____________________________________________________________________
Dr. William Pence                       pence at milkyway.gsfc.nasa.gov
NASA/GSFC Code 662       HEASARC        +1-301-286-4599 (voice)
Greenbelt MD 20771                      +1-301-286-1684 (fax)