Video-chain total detection noise measured in the initial data treatment (Fabricius et al. 2016) from individual telemetry packets for SM (magenta), AF1 (green), XP (grey) and RVS high resolution (cyan) versus time over an arbitrary, example 10-month period from January 2016 to October 2016 inclusive. The horizontal axis is labelled in revolutions (units of 6 h). The scatter for a given instrument, i.e. in points of a given colour, is dominated by the range in offset level amongst the CCDs of that instrument and not instability in the offset level of any one device.