Active surface control system look-up table. There are 11 elevation angles in the look-up table, φ_⊥FEM, with the 32 deg set to zero displacements. Each panel shows the elevation angle, α, and its rms value in microns, δ_rms. The contour lines are between – 2000 µm and 2000 µm, with 400 µm intervals. The actuators maximum displacement is of ±5 mm. It is instantly noticeable stronger corrections for an angle closer to 90 deg. The dominant aberrations are first and second coma.