COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 291

                                Konkoly Observatory
                                Budapest
                                1968 August 5


                    CH CYGNI


Preliminary reductions of recent photoelectric observations reveal a new
increase in luminosity of the star, with strong oscillations, particularly in
U-light, up to about three tenths of magnitude in a few minutes. For
comparison sake, rounded off values are given for the following epochs:

                  V     B-V    U-B
Dec.  9   1967   8.0   +1.3    0.0
Apr. 21   1968   7.1   +1.2   -0.15
   " 23          6.9   +1.1   -0.3
June 27          6.7   +1.1   -0.4
July 13          6.7   +1.1   -0.4


                                  BRUNO CESTER
                            Observatorio Astronomico
                                    Trieste





              NOTE ON THE RRab STAR AN SERPENTIS


On the basis of visual and photographic observations BATYREV^1 determined a
secondary period of 22.94 days for this star from the phase oscillations of
maxima, his result was, however, very doubtful.

In order to investigate the suspected light curve variations of this star, in
the years 1967 and 1968, more than one thousand photoelectric observations have
been obtained in yellow, blue and ultraviolet with the 24 inch telescope at the
Konkoly Observatory. But no significant variations in phase or height of the
six observed maxima have been found.

In addition, our observations are in good agreement with the observations
obtained by FITCH, et al.^2 in 1965. Moreover, the O-C diagram of this
variable is very simple which also makes absence of light curve variation
probable.

The Table contains the times of the observed maxima the O-C values computed by
the following elements:

Max.hel.=J.D. 2439538.6742+0.^d5220716*E

and the heights of the maxima relative to the comparison star in the
instrumental system.

J.D.max.hel.       O-C      Delta M_y   Delta M_b
2439537.632     +0.^d0019   -0.^m35:      -
    538.6745    +0.0003     -0.32       -0.^m69
    547.5485    -0.0009     -0.30       -0.69
    560.602     +0.0008     -0.29:      -0.70:
    617.5050    -0.0020     -0.30       -0.66
    996.5310     0.0000     -0.29       -0.69


                                      B. SZEIDL
                                 Konkoly Observatory
                                      Budapest

1/ A.A. Batyrev, 1964, Peremenny Zvezdy 15, 278
2/ W.S. Fitch, W.Z. Wisniewski and H.L. Johnson, 1967, Comm. Lunar and
   Planetary Laboratory No 71, Vol. 5, Part 2.