COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                       Number 927

                                     Konkoly Observatory
                                     Budapest
                                     1974 September 30


               PHOTOELECTRIC UBV OBSERVATIONS
            OF THE RR LYRAE-TYPE VARIABLE XZ CYG

    The variable XZ Cyg has been observed photoelectrically at
the Odessa Observatory near Majaky (USSR) with the 22-inch 
reflector, during the period from August 7 to October 16, 1972.

Max.hel.    O-C      Max.hel.    O-C     Max.hel.    O-C

2441...
537,3312  -0d,0608   564,4249  -0,0239   573,2764  -0,0358
541,5233   -0,0672   565,3529  -0,0289   591,4432  -0,0623
543,3882   -0,0682   566,2864  -0,0284   593,3077  -0,0639
544,3236   -0,0658   567,2214  -0,0264   594,2432  -0,0614
548,5291   -0,0588   571,4141  -0,0322   598,4346  -0,0685
550,4078   -0,0461   572,3438  -0,0355   599,3725  -0,0636
                                         607,3132  -0,0533

     The table shows the moments of the nineteen maxima obtained
in B and the corresponding O-C's. The data for O-C were calculated 
with the elements:

     Max.hel. = 244 0445,789 + 0d,466497.E:

    The figure shows the change of the B magnitudes at maxima and
minima and the corresponding O-C values versus the phase Psi of the
secondary cycle. The phase Psi was calculated with the help of the
elements:

          Max. A. J.D. = 2441571,50 + 57d,52 . N

which we have found for our observing season.
    The B-max curve is displaced with respect to the O-C curve
0,12 of the secondary cycle.


     [FIGURE 1]
                                  P. KUNCHEV

                               University of Sofia,
                               Bulgaria.
                               Odessa Observatory, USSR.