Robert C. Byrd Green Bank Telescope
NRAO Green Bank
Joe Brandt, Richard Prestage
January 7, 2014
GBT Software Project Note 7.15
The GBT Antenna Control Unit FITS File Specification
The FITS format structure is presented for the GBT Antenna Control
Unit (ACU) 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 main content of the ACU FITS file is a binary table containing
a stream of the actual (indicated) telescope positions sampled at
10Hz through-out the scan.
- 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 description of contents of MAJOR and MINOR if INDICSYS
is OTHER. Subsequent changes to the content of this document should
increment the document version number (Richard Prestage).
- 16th October 2002
- Added information for initial implementation of
beam offsets and multi-feed support. FITSVER revised to 1.3.
- 24th June 2003
- Added OBSC_AZ and OBSC_EL columns. FITSVER revised
- 9th July 2003
- Added SOBSC_AZ, SOBSC_EL, SMNT_AZ, SMNT_EL, SDMJD,
OFFSYS, and ORADESYS primary header keys. FITSVER revised to 1.5.
- 15th December 2003
- Added DYN_ENA, SDYN_AZ1, SDYN_AZ2, SDYN_EL,
SDYN_FTKYP, to primary header keys. Added DYN_POINT and DYN_FOCUS
tables. FITSVER revised to 1.6.
- 30 Apr 2004
- Added notes on beam offset table references. FITSVER revised to 1.7.
- 28 Feb 2006
- Corrected 300ms offset in OBSC_AZ and OBSC_EL columns. FITSVER revised to 1.8.
- 24 Mar 2006
- Added LFC_* and FTRK* primary header keywords. FITSVER revised to 2.9.
- 17 May 2006
- Added WEATHSTA primary header keyword. FITSVER revised to 2.10 (First Linux version.)
- 1 August 2007
- Revised to implement pointing Model 5, revising FITSVER to 2.11. Added additional primary header keywords for new model.
- 28 September 2007
- Revised to correct an error introduced in the FITSVER 2.11 version. The version 2.11 files have an error in the SOBSC_EL keyword and OBSC_EL column. The values omit refraction. The correct values for OBSC_EL may be obtained by adding the values from the REFRACT column.
- 31 Jan 2008
- Revised description of OBSC_AZ and OBSC_EL columns in primary table to include modal behavior. No version revision.
- 28 March 2008
- Revised to indicate changes in manager, no FITS format changes.
- 14 May 2010
- Revised section 1.6 to fix error in sign of equations showing how to apply the beam offsets.
- 10 Jan 2010
- Revised for new Beam specification syntax. FITSVER 14.
- 7 Jan 2014
- Added plate scan keywords PLSCALXT and PLSCALZT. FITSVER 15.