GRAVITY data, best-fit model, and pure MARCS model fit for AH Sco. Upper panel: normalised flux for the RSG AH Sco (grey), as observed with VLTI/GRAVITY for the K band. Our best-fit model is shown in red for RE, while the pure MARCS model fit is shown in green. Lower panels: same as the upper panel but for the |V|² with different baselines. Both flux and |V|² are better represented by our fit.