PHOTOMETRIC-STUDY OF RS GRU AND RY LEP

Simultaneous uv by beta photometric observations of the high-amplitude delta Set-type stars RS Gru and RY Lep have been collected and new ti mes of light maxima have been obtained. Using the classical O-C method , it is found that the pulsation of RS Gru can be well described by me ans of a quadratic ephemeris with the period decreasing at a rate of d P/Pdt = -10.6(+/-0.8)10(-8) yr(-1) over more than 30 yr. Intrinsic b-y , m(1) and c(1) values are derived and the physical parameters of thes e two stars are determined.