B,V Ic correspond to the band in which the brightness was measured. (The survey instrument uses a CCD camera and wide field lens). V corresponds roughly to what the eye sees Ic is the near infrared. There are small long term average trends from season to season but the variation from day to day/week to week of up to 0.5 magnitudes seen in the V data would be obvious by eye if real. The very tight error bars on the points would suggest they are real but I am somewhat sceptical.