COMMISSION 27 OF THE I. A. U.
                INFORMATION BULLETIN ON VARIABLE STARS
                            Number 1863


                                          Konkoly Observatory
                                          Budapest
                                          1980 November 12

                                          HU ISSN 0374-0676



                PHOTOELECTRIC MINIMA OF DO CASSIOPEIAE




     The times of minima of eclipsing variable DO Cas were photoelectrically 
determined with a 48 cm Cassegrain telescope at
the Ege University Observatory. The photometer is equipped with
an EMI 9781 A photomultiplier tube and the standard Johnson B,
V filters.
     The heliocentric minima are listed in Table I, where (O-C)
values of DO Cas were computed with the help of the light elements 
given by Cester et al. (1977).
     Min I = JD Hel. 2433926.4573 + 0.6846661d.E.

                    Table I

  JD Hel.         E      (O-C)   Filter
2444485.37800   15422   0.00011    B
       .37855   15422   0.00066    V
    498.38564   15441  -0.00091    B
       .38584   15441  -0.00071    V

  The photoelectric times of the minima which have been obtained 
so far by other observers are also shown in Figure 1.The
(O-C) values were computed again from the above given equation
and plotted against cycles.
  If the observations obtained in the recent years are examined 
one can easily assume that DO Cas exhibits decreasing period,
since some (O-C) values obtained by other researchers do not fit
to the above given equation. But the latest observations of this
star, presented in this paper clearly indicate that (O-C) values
fit very well to the equation given by Cester et al.(1977).

                    [FIGURE 1]

Figure 1. Dots and circles indicate the observations from
other researchers and observations obtained at Ege University
Observatory, respectively.



                      O. TUMER and S.EVREN
                      Ege University Observatory
                      Bornova-Izmir
                      Turkey




Reference:

Cester, B., Giuricin, G., Mardirossian, F., and Pucillo, M.,
      1977, Astron. Astrophys. Suppl. 30, 223 [BIBCODE 1977A&AS...30..223C ]