Squared visibility and phase differences between a 1 mas star with a transiting exoplanet at (0.2,0.0) mas and a single star at different spatial frequencies (1.1 × 10⁸ (1/rad), top; 2.1 × 10⁸ (1/rad), middle; 3.4 × 10⁸ (1/rad), bottom). Squared visibilities: solid lines: absolute errors (1%, red; 2%, blue; 0.5%, green). Dashed lines: errors corresponding to different S/N: 5 (blue) and 20 (red). Phases (in degree): 2° (red) and 20° (blue).