COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1737

                                       Konkoly Observatory
                                       Budapest
                                       1980 January 30


               THE LIGHT CURVES OF RT CrB


The RS CVn-type eclipsing binary RT CrB has been observed in B and V colours at
the Ege University Observatory from April 26 to July 30, 1979. The
observations were made with the 48 cm Cassegrain telescope equipped with EMI
9781 A photomultiplier. For comparison and check stars BD+29d2691 and
BD+29d2692 were used, respectively. A total of 288 observations were obtained
on 32 nights.

The phases of the observations have been computed from the following light
elements given in the second supplement to the GCVS (1969),

Min I = JD Hel. 2428273.28+5.11712d*E.

The differential observations in the sense comparison minus variable have been
plotted against phase and are shown in Figures 1 and 2. Corrections for
atmospheric extinction on differential observations were too small to be taken
into account. Although, there is a large scattering in the light curves, a
wave-like distortion can still be distinguished. The amplitudes of the wave
are about 0.04m and 0.03m in yellow and blue lights, respectively. The
maximum of the wave is around phase 0.05, while the minimum is around phase
0.55.

The observations of the system will be carried on in the next observing
seasons.


A.Y. ERTAN, Z. TUNCA, S. EVREN
O. TUMER, M. KURUTAC and C. IBANOGLU
Ege University Observatory
Bornova-Izmir, Turkey


                         [FIGURE 1]

              Figure 1.  B light curve of RT CrB.


                         [FIGURE 2]

              Figure 2.  V light curve of RT CrB.