COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                NUMBER 863

                           Konkoly Observatory
                           Budapest

                           1974 January 16


      ON THE LIGHT VARIATIONS OF CI Cyg IN 1973


  Photographic observations of the symbiotic star CI Cyg
through 1890-1967 showed light variations with a period equal
to 855d and an amplitude of about 1 magn. having considerable
dispersion (m_pg 0.5m) (N.K.G. Greenstein HB 906, 5, 1937; L.H. Aller
Publ. Astroph. Obs. 9, 343, 1954; D. Hoffleit Irish Astr.J. 8, 149,
1968.) The  form of the light-curve was stable enough. However,
two outburst were noted in 1911 and 1937 when the brightness
of the star reached m_pg = 10.7m and m_pg 10.2m respectively. The
duration of each outburst was about 200d. In 1971-72 the brightness 
of CI Cyg increased once again up to m_pg = 9.9m (W.M. Lowder
IAU Circ. 2335, 1971; D. Hoffleit IAU Circ. 2336, 1971; F.M. Stienon
BAAS 5, 17, 1973; M.W. Mayall J.R., A.S. Canada 67, 101, 1973).

                      [FIGURE 1]

  Through 1973 June-October 7 UBV observations of CI Cyg
were made at the Crimean Astrophysical Observatory. These 
observations (s. Fig.) showed an outburst during this period. The
maximal brightness was about 9.7m in V, 10.5 in B, which is
close to the photographic magnitude. 
  Thus a considerable increase of CI Cyg was observed twice
during 1971-1973. That indicates a possible increase of the 
activity of this star as far as during 1890-1967 only two outbursts
were noted. It should be noted that the outbursts of 1911  and
1937 occurred  at the maximum of the composite light-curve and
outbursts of 1571-72 and 1973 arised immediately after the minimum.


 Crimean Astrophysical 				T. S. BELYAKINA
   Observatory