Robert C. Byrd Green Bank Telescope
NRAO Green Bank
December 17th, 2001
GBT Software Project Note 6.5
The GBT Tracking Local Oscillator FITS Keyword Definitions
The FITS format structure is presented for the GBT tracking local
oscillator (LO1) scan data files. The scan data FITS files are permanently
archived after each observation, and will usually be input to the
aips++ filler, which has the task of combining all scan data FITS
files into an aips++ Measurement Set. This data may then either be
processed further in aips++, or written out in an aips++ supported
FITS format (one of which is single dish FITS).
The LO1 FITS files, produced separately for each LO contains binary
tables describing the commanded LO1 frequencies as a function of time
throughout the scan. This is separated two components separately describing
the effects of Doppler tracking frequency switching.
- 8th November 2001
- Penultimate definition of FITSVER 1.1; released
for general comment (Richard Prestage).
- 16th November 2001
- Final version agreed for implementation of
FITSVER 1.1. Added keywords SITESYS and SITETYPE, and modified
discussion of SITELONG, SITELAT, SITEELEV. Changed actual values
used. Changed discussion of VELDEF, and move to SOUVEL binary table.
Noted VFRAME and RVSYS are true (relativistic) velocities
Subsequent changes to the content of this document should
increment the document version number (Richard Prestage).
- 17th December 2001
- Documentation corrections for FITSVER 1.1;
table names (LO1STATE renamed to STATE, LO1TABLE renamed to LO1TBL),
added LSTSTART keyword (Joe Brandt).
- 15th July 2002
- Documenation corrections for FITSVER 1.2;
Revised wording of RVSYS keyword and corrected the equation associated
with calcuating RVSYS.
- 18th September 2002
- Documenation corrections for FITSVER 1.3;
Corrected values of SOUVEL table velocity columns to meters/second.
Fits files written with FITSVER of 1.2 and below contain values which
were incorrectly written in km/sec rather than meters/sec.
- 3rd April 2008
- Documentation change; clarification of meaning of FREQOFF
values in STATE table (Bob Garwood).