Fig. 4 --- Top Panel - A representative high signal-to-noise light curve of a non-variable star taken from our KPNO 0.9-m observing run. The five figure sections represent the five nights of the observing run. The star is observed for 4.5 hours on each night. The standard deviation measured for this star is 0.0020 magnitudes and this agrees with the mean precision of the data points in the light curve, showing that we meet the theoretical limit for precision given the finite number of photons collected from this star.
Middle Panel - A light curve of a high-amplitude variable taken from the same dataset. This star is probably a short-period eclipsing binary.
Bottom Panel - A light curve for a low-amplitude variable star of unknown type.