All data of night 9 (t_exp = 9360 s), derotated, averaged, and corrected for telescope polarization: the top half shows I and the bottom half Q_ϕ with corresponding colour scales in ct/(px · DIT) as in Fig. 5. Artificial point sources are inserted at different separations and contrasts C_I and C_P are changed with position angle as indicated. Counts inside 0.9″ are scaled down for better visibility with a factor of six for I and a factor three for Q_ϕ.