Typical illumination pattern from a point-like source. Here R_diff = 100 km, the screen is at z₀ = 160 pc, λ = 2.16 μm, then R_F = 1300 km and R_ref = 106 000 km. The typical length scale of the small-scale speckles is R_diff, and the scale of the larger structures is R_ref. The white square shows our fiducial zone with a margin of L_m = R_ref/2 from the borders. Grey scale range from 0 to 4 times the mean intensity. The image has 20 000 × 20 000 pixels, each with a 22.6 km side.