Temporal response changes
In some C100 measurements the signal varies on timescale of 10 sec
increasing the noise of the measurement. These signal fluctuations
seem to be due to temporal response changes. No correction algorithm is
currently available.
Chopping offsets
For chopped measurements, any positive or negative signal offset in the
off-position causes a virtual difference signal. Such systematic difference
signals have been observed and are likely due to inhomogeneities in the
instrument's field of view. All chopped observations are probably affected by
this effect. Calibration observations have been performed and are being
analysed in order to determine correction factors to be included in the
off-line data processing.
Flatfield accuracy
A good flatfield correction for the C100 and C200 arrays is necessary to
determine the noise level of the background. The accuracy of the flatfield
becomes important when difference signals are determined among individual
pixels. It is also important in case a map is created from several (raster)
pointings. Individual drift behaviour for the different pixels may increase
the flatfield uncertainty.