COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2361

                                   Konkoly Observatory
                                   Budapest
                                   27 June 1983

                                   HU ISSN 0374-0676





         PERIOD CHANGE OF THE RR LYRAE STAR XZ CYGNI




 From my series of regular visual and photographic observations of XZ Cyg
(see for instance Mitt. Verand. Sterne Sonneberg 9,p. 82) I derived the O-C
diagram given in the figure. It is based on the elements of the main table
of Suppl. 3 (1976) to the GCVS:

          C = 244 1453.3856 + 0.4664731d*E.


 A rather strong increase of the period around 1978 was noted already by
Taylor (AAVSO Journal 8, p. 1; 1979). From my observations the new period of
                  0.4666909d
can be found for the time after 1979.6. This period seems to have been stable
for three years at least. In the figure the dots represent data of well

                         [FIGURE 1]
 
observed maxima; the curved line shows the trend of Taylor's observations
(l.c.), properly reduced.





                       H.-J. BLASBERG

                  Arbeitskreis "Veranderliche" (AKV)
                  im Kulturbund der DDR
                  DDR-8053 Dresden, Tolkewitzer Strasse 44