Pareto front for the intrinsic source at 86 GHz across each self-calibration iteration. Arranged from left to right, the panels correspond to the first, second, and third iterations, respectively. In the initial iteration, the ring structure is absent from the solution set. A hint of the ring appears in the second iteration, meaning the null in the visibilites is presented in the set of local minima. In addition, we note how the diversity of solutions increases. The red box encapsulates the most frequently repeated (most probable) solution, the blue box highlights the solution closest to the ideal, and the green box identifies the one with the lowest χ².