We performed 48.6 hours ( in 28 nights ) of simultaneous B and V band observations of the flickering variability of the recurrent nova RS Oph in quiescence .
During the time of our observations the brightness of the system varied between 13.2 > B > 11.1 and the colour in the range 0.86 < B - V < 1.33 .
We find that RS Oph becomes more blue , as it becomes brighter , however the hot component becomes more red as it becomes brighter ( assuming that the red giant is non-variable ) .
During all the runs RS Oph exhibits flickering with amplitude 0.16 - 0.59 mag in B band .
For the flickering source we find that it has colour -0.14 < B - V < 0.40 , temperature in the range 7200 < T _ { fl } < 18900 , and average radius 1.1 < R _ { fl } < 6.7 R _ { \odot } .
We do not find a correlation between the temperature of the flickering and the brightness .
However , we do find a strong correlation ( correlation coefficient 0.81 , significance 1.1 \times 10 ^ { -7 } ) between B band magnitude and the average radius of the flickering source – as the brightness of the system increases the size of the flickering source also increases .
The estimated temperature is similar to that of the bright spot of cataclysmic variables .
The persistent presence of flickering indicates that the white dwarf is actively accreting material for the next outburst .