COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 1602 Konkoly Observatory Budapest 1979 May 11 OBSERVATIONS OF CI Cyg IN 1977-78 Photoelectric observations of the symbiotic eclipsing binary star CI Cyg have been continued in 1977-78. (Belyakina, 1976, 1979). The results of these observations in instrumental photometric system are plotted in Fig.1. From Fig.1 one can see that the brightness of CI Cyg has decreased as compared with 1975 (Belyakina, 1976). Besides the variable star did not have any great outburst in this period. A deep minimum in the period JD 2443490- 600 corresponds to the regular eclipse of the hot component by the cold one (Belyakina, 1979). Unfortunately CI Cyg could not be observed in this period and the detailed light-curve was not obtained. The small smooth fluctuations are also seen over all the curves of Fig.1. Their amplitudes are close to 0.1m-0.2m and their durations are about 10-50 days. [FIGURE 1] [FIGURE 2] Fig.2 shows a correlation between the light-curve (in system B) of the eclipses of 1975 and 1977-78 (dots and open circles accordingly) and combined photographic one of CI Cyg before an outburst in 1971 (line). A cross placed near the last curve corresponds to the B magnitude of CI Cyg in 1966 (Belyakina, 1967). One can see that the duration of the minimum in 1975 was close to that of 1977-78 but they had different depths. Besides in 1975 the variable star was brighter before eclipse than after it. The reverse situation was observed in the minimum of 1977-78. T.S. BELYAKINA Crimean Astrophysical Observatory 334413 Nauchny, Crimea, USSR References: Belyakina, T.S. 1967, Izv. Krimsk. Astrophys. Obs. 38, 171 Belyakina, T.S. 1976, I.B.V.S. No. 1169 Belyakina, T.S. 1979, Izv. Krimsk. Astrophys. Obs. 59