During observations of solar system objects some problems where noted
with differential tracking. The system works properly when the
autoguider is used, including for rather high (400 arcsec per
hour!) differential tracking rates. However, data taken with the
telescope tracking without using the autoguider show very significant
distortions and is much poorer than one might expect. The data points
to some problem in the way non-sidereal tracking rates are applied.
This is currently being investigated.