Left: probability density function from the distribution of samples in the u − v plane for the 4 configurations used here (numbers 5, 10, 15, and 20, indicated next to each curve) as a function of u − v radius . The relevant parameters are the source position and duration of observation, which are described in Sect. 2.3. The small vertical lines indicate the minimum baseline for each configuration. Also marked, with dashed lines, are characteristic baselines d_uv = cD/(2πν₀d) corresponding to a physical size d = 10   AU at a distance D = 150   pc, for the six frequencies ν₀. Right: power spectra of the input maps at 100 GHz (solid lines) and 661 GHz (dashed lines) for θ = 0°. The wavenumber axis has been rescaled to match the u − v radius of the left plot. The vertical black lines mark the positions of the 10 AU scale at 150 pc at these frequencies (solid for 100 GHz, dashed for 661 GHz, reported from left plot).