Dark blue points: light curve extracted from a CHEOPSim image time series, using photometric extraction performed by the data reduction pipeline that will be used with real CHEOPS data, for planet π Men c (radius 2.04R_⊕, orbital period 6.27 days), orbiting the star Pi Mensae (V = 5.67, spectral type G0V). The exposure duration is 0.35 s and the exposures are stacked with stacking order 33. In reality this target cannot be observed by CHEOPS due to its location close to the Southern Ecliptic Pole, a region which is excluded due to the 120° Sun-avoidance exclusion angle, but has been chosen as it allows comparison of the photometric abilities of the CHEOPS and TESS missions. Stray light from the Sun has not been modelled. Gaps in the light curve correspond to interruptions due to Earth occultation (once per CHEOPS orbit). The gaps here are close to worst case, since the target is close to the Southern Ecliptic Pole, and CHEOPS has a polar Earth orbit. The simulated photon flux from the target star incident on the telescope, without stellar granulation, is shown by the red line. An example image is shown on the right. Pale blue-grey points: phase folded light curve for the planet π Men c as measured by TESS (Huang et al. 2018).