Observed minus calculated (O − C) diagram of TOI-1130 b (top) and TOI-1130 c (bottom) from the photo-dynamical fit with TRADES of the ground-based T₀s (orange and black circles, with the simulated ones being as open orange circles) of photometry described in Sec. 4.1. The O − C has been computed with the linear ephemeris in Tables A.2 and A.3. Observed transit times of TESS and CHEOPS, not used in the fit, have been over-plotted (as colour-coded squares) on the O − C and residual panels, full MAP model as black line with 1σ grey-shaded area, that is almost invisible because the model is very well constrained. Times in BTJD = BJD_TDB − 2 457 000.