COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2083

                                 Konkoly Observatory
                                 Budapest
                                 1982 February 8

                                 HU ISSN 0374-0676




       TWO (O-C) RESIDUALS OF W URSAE MAJORIS SYSTEM




  The well known short period (0.333d 63808) eclipsing variable,
W Ursae Majoris (BD+56d1400) was observed with a photoelectric
photometer attached to the 48 cm Cassegrain telescope at the
Ege University Observatory, Izmir. The observations were carried
out on January 16-17, 1982 on two nights of excellent sky conditions, 
which are rare for this time of the year. The first night
complete light curve and the second night the primary minimum
were obtained. On both nights the (BD+56d1399, 8.5m) star was
monitored as a comparison star with EMI 9781 A as a detector.

                        [FIGURE 1]

 Fig.1: Two primary minima of W UMa obtained on 16-17 Jan., 1982


The star is well known for the variation of its orbital period
and there are observational evidences for the oscillatory variations 
within the (O-C) residuals. Also there are some other indications 
of the second oscillatory variations superimposed on
the (O-C) residuals.
  We shall present a discussion somewhere else on these oscillatory 
variations of the (O-C) residuals.

   Our (O-C) values are,
   (O-C)_1= -0.005d = -7.27m (January 16,1982)-(O-C)_II 0.0053=7.63m
   (O-C)_2= -0.0045d= -6.48m (January 17,1982)

for which,

  Hel Min I= JD 243 7986.9742+0.33363808d.E

was adopted. On the other hand our accurate observed time of
primary minimum are:

   JD_1 = 244 4986.3624; JD_II= 244 4986.5290
   JD_2 = 244 4987.3639





Acknowledgements
  We would like to express our gratitude to Mr. E. Kucuktaka
and to Mr. O. Tumer for their help.




             E. HAMZAOGLU, V. KESKIN and T. EKER
                  Ege University
                  Department of Astronomy
                  Bornova-Izmir
                  Turkey




References:
Mikolajewska, J. and Mikolajewski, M., 1980, IBVS No. 1812.
Rucinski, S.M., Gondhalekar, P., Pringle, J.E. and Whelan, J.A.J.,
    1980, IBVS No. 1844.