The FITS format structure is presented for the GBT spectrometer
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 scan data FITS files contain both 1) a complete description of
the spectrometer setup for the observation and 2) measurement data
with a FITS keyword description of the data organization. The
ACT_STATE, PORT, STATE and SAMPLER tables describe the setup and
the DATA table contains measured values.