zeropoint temporalevolution (for the CCD in row 6, strip15 and Fov1). The red arrows indicatethe decontamination events that resulted in an improvement of the zeropoint. After the decontamination at OBMT 2330.6, there is no degradation of the RVS transmission, and the decontamination events become rarer over mission time. The trending epochs are indicated in the same way as in Fig. 4. During the first trending epoch, a wrong catalogue was used, and the zeropoint data obtained in this epoch should be offset by ~ + 0.08 magnitudes.