Left column: magnification of the V → QU crosstalk at 526.2 nm for observations taken between UT 20 and 24. Individual maps lasted for approximately 30 min. Most scans show a dominant parabolic shape of the crosstalk values (seen also in Fig. 10). Only the central position of the scan yields a value that agrees with the 2010 telescope model. Right column: same for data taken in 2017 at 614.9 nm with the SPINOR modulator in a collimated beam.