Raw light curves (points) for WASP-103b observed with HST/WFC3 (top four panels) and Spitzer/IRAC (bottom two panels). The black lines show the best fit models, which include the astrophysical signal and instrument systematics. The gray lines indicate the contribution from the instrument systematics alone (which would be observed for a source with constant brightness and no planet). For visual clarity, we corrected the HST data for the upstream-downstream effect and zoomed in on the phase variation, so the transits are not displayed in the panel.