Graphic determination of the relative nulling efficiency ρ₀ of a Bracewell nulling interferometer through a stereographic projection of the Fresnel vector z = e^{πλ₀ / λ} toward point 1 on the real axis. The relative nulling efficiency of the iterative Bracewell scheme (P_n,Q_n) is . This quantity decreases to 0, as n increases where  | ρ₀ | <1. That is when ρ₀(z) is in the (−j,j) segment. Therefore, a planet dephased by π at λ₀ relative to its star may be detected in many bandwidths whose first order is .