Figure 8 plots the log(Exposure time (secs)) needed to reach a given
Figure 8: Calculated exposure times for various conditions.
magnitude at a S/N of 5 and 20, for seeing conditions of 0.564''\ (ie 1 '', ie for surface brightness), 0.8'' and 1.2'', and for apertures of radius 2.5 seeing, observing in ND_STARE mode.