Example of change in the uv-plane modeled with the ASPRO2 software. Left: global view of the uv-plane. Different colors are for different pairs of telescopes (baselines). Right: zoom on the change in the uv-plane for the fastest moving baseline. Each straight black line indicates the uv-coordinate for this baseline for an instant snapshot, and each snapshot is separated by 5 min. The regularly spaced, orange lines display the V2 values modeled for a binary with a separation of 50 mas.