Impulse response from unitary point sources in plane D, in logarithmic scale. The angular coordinates of the point sources are β = 0 and, from left to right, α = 0.995 R_⊙, α = 1.010 R_⊙, α = 1.025 R_⊙, α = 1.040 R_⊙, α = 1.055 R_⊙, α = 1.070 R_⊙, α = 1.085 R_⊙, α = 1.100 R_⊙, α = 1.115 R_⊙ and α = 1.130 R_⊙. a) Reference system without external and internal occulters. b) Complete system S_EL. The two vertical lines represent the limit of the fully vignetted zone ρ_0% and the limit of the fully unvignetted zone ρ_100%.