[fitsbits] FIT Keyword data dictionaries

[William Pence]

FITS Keyword Data Dictionaries - A Progress Report
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Last year, a NASA-sponsored committee that coordinates activities at
different NASA data centers (the ADCCC) appointed a FITS Coordination Group
(FCG) to look into ways of improving the interoperability of the FITS data
products generated and distributed by different projects or observatories. 
The FCG has about a dozen members representing many major international
astronomical data centers.

One of the initial projects of this Group has been to set up a simple web
page (at http://legacy.gsfc.nasa.gov/fcg) with links to other known FITS
keyword data dictionaries.  These dictionaries typically define the meaning,
allowed range of values, and units, of the keywords used by a particular
observatory or instrument.

In addition to the list of existing FITS keyword dictionaries, the FCG also
compiled it's own data dictionary of commonly used FITS keywords that have
wide applicability and that are not already defined in the FITS Standard
document.  Conceivably, this list of common keywords might eventually be
added as an appendix to the FITS Standard.

We would be interested in any comments from the FITS community at large
about this work.  In particular, please tell us about any other existing
FITS keyword data dictionaries that could be added to our list.  Secondly,
we would welcome suggestions of other keywords that should be added to our
dictionary of commonly used keywords, or objections about any of the
keywords currently in the dictionary.  This dictionary is available in html
or postscript format from the above FCG web page. For reference here are the
70 keywords that are currently defined in this dictionary, 

1. Keywords that describe the data or the FITS file itself:

    TITLE FILENAME FILETYPE ROOTNAME
    PROGRAM CREATOR CONFIGUR
    NEXTEND HDUNAME HDUVER HDULEVEL
    TLMINn TLMAXn TDMINn TDMAXn TDBINn
    TSORTKEY PROGRAM CREATOR CONFIGUR
    HDUCLASS HDUDOC HDUVERS HDUCLASn

2.  Keywords that describe the observation:

    SUNANGLE MOONANGL
    RA DEC RA_NOM DEC_NOM
    RA_OBJ DEC_OBJ RA_PNT DEC_PNT PA_PNT
    RA_SCX DEC_SCX RA_SCY DEC_SXY RA_SCZ DEC_SCZ
    ORIENTAT AIRMASS LATITUDE
    OBJNAME OBS_ID

3.  Keywords that describe the instrument that took the data:

    OBS_MODE DATAMODE
    APERTURE DETNAM FILTER FILTERn GRATING GRATINGn
    SATURATE

4.  Keywords that give the date or duration of the observation:

    TIME-OBS TIME-END DATE-END
    EXPOSURE EXPTIME TELAPSE ELAPTIME ONTIME LIVETIME

5.  Keywords that denote non-standard FITS keyword format conventions:

    HIERARCH INHERIT CONTINUE

6.  File checksum keywords:

    CHECKSUM DATASUM CHECKVER

7.  Hierarchical file grouping keywords:

    GRPNAME GRPIDn GRPLCn


- Bill Pence
(on behalf of the FCG)
____________________________________________________________________
Dr. William Pence                          pence at tetra.gsfc.nasa.gov
NASA/GSFC Code 662         HEASARC         +1-301-286-4599 (voice)     
Greenbelt MD 20771                         +1-301-286-1684 (fax)