  An improved way of taking off-source data for background determination in
Cherenkov telescope observations is proposed. Generalizing the traditional
concept of taking on-source/off-source observations of equal duration (e.g. 30
minutes ON followed by 30 minutes OFF), Faster Background Determination (FBD)
permits an off-source observation with the same zenith angle distribution as
the on-source observation to be obtained within less time. The method permits
the on-source observation time to be maximized without compromising the quality
of the background determination. It also increases the signal significance for
strong sources. The only modification necessary in the data acquisition is a
small change to the tracking algorithm. The only modification necessary in the
data analysis is to introduce a time normalization which does not increase the
systematic errors. The method could become the normal observing mode for
Cherenkov telescopes when observing strong sources.
