Comparison between the normalized count rate (magenta diamonds) of β 01 Scorpii and the normalized VF (black dots). The VF is evaluated in the same positions of the star along the FoV. The black dashed line represents the continuous trend of VF. All trends have been normalized to the value of the first frame of this observation. In the figure, a discrepancy between the star signal and the VF trend is evident, on the east and the west sides of the UV FoV. The star signal error bars are multiplied by a factor 3 for clarity of the plot. The trend of the count rate corrected for the VF is shown in the first panel of Fig. 7.