First panel: 2013–2014 MOST light curve of FU Ori provided by the pipeline. The standardised SAAO UBVR_cI_c (filled circles) and aligned MSO BVRI light curves (open circles and crosses) are shown in the second panel. Third panel: averaged SAAO BVR_cI_c (filled circles) and MSO BVRI (open circles) observations used for correction of the instrumental trend in the original MOST data, as described in Sect. 2.1. The de-trended MOST data are plotted in the same panel. Fourth panel: de-trended MOST data in the form of orbital averages with error bars (σ).