Examples of reduced squared visibilities, V², of the science targets, ε, δ, ζ, and σ Ori. Measurements are from nights: 20 November 2023, 22 November 2023, 8 January 2024, and 23 November 2023, respectively. Science targets are with obvious signals from companions. For the single star ε Ori, the signal suggests an elongated or non-spherical shape, unlike the calibrator ζ Lep, which exhibits a perfectly spherical shape. Colours correspond to individual baselines. The squared visibilities of calibrators are in Fig. C.3.