RV Tauri and the RVB phenomenon. I. Photometry of RV Tauri

I present new photoelectric observations of RV Tauri. Period analysis revealed that the amplitude of the long period variation has decreased drastically since the start of the century while the amplitude of the RV Tauri- like variation remained practically the same. The change in the short period shows the same kind of cyclic O C diagram as the other variables of this class. While a pulsational origin seems unlikely in the case of the long term variation, its decreasing amplitude indicates that simple binarity could not be used in modelling the RVB phenomena.