COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1736

                                 Konkoly Observatory
                                 Budapest
                                 1980 January 30


        PHOTOELECTRIC MINIMA OF VW CEPHEI


Photoelectric observations on the peculiar eclipsing binary VW Cep 
(HD 197433=BD+75d752, G5) were carried out, in B and V, during September 1979.
The observations were made using the two-beam, multi-mode, nebular-stellar
photometer of the National Observatory of Athens attached to the 48-inch
Cassegrain reflector at the Kryonerion Astronomical Station.

The stars HD 192889 (G5, Pt_m=8.12) and HD 192635 (F5, Pt_m=8.1) were used for
comparison and checking, respectively. The filters used are in close
accordance with the standard ones. Reduction of the observations has been made
using Hardie's method (1962). Every observational night (13/14, 14/15, 18/19
and 21/22) the observations were carried out for several hours thus, we
succeeded in obtaining 3 complete light curves and 8 minima.

The following Table gives the Hel.J.D. of the 8 minima, the differences (O-C),
the mean error sigma, and the type of minimum. The times of minima and the
mean errors have been calculated using the method of Kwee and Van Woerden
(1956); while the ephemeris used is that of Kwee (1966).

Table

Hel.J.D.    (O-C)     sigma     Minimum
2444000+    days      days
130.4162   -0.1052   +-0.0007    I
130.5558   -0.1047   +-0.0008   II
131.5278   -0.1068   +-0.0002    I
135.2859   -0.1060   +-0.0005   II
135.4254   -0.1057   +-0.0006    I
135.5648   -0.1055   +-0.0004   II
138.3480   -0.1054   +-0.0003   II
138.4866   -0.1060   +-0.0002    I

Our O-C values indicate that the period of the system continues to decrease.
(See for instance the residual diagrams of van't Veer (1973) of Hopp et al.
(1979)).


P. ROVITHIS
National Observatory of Athens, Athens (306)
Greece

H. ROVITHIS-LIVANIOU
Astronomy Department
Athens University
Panepistimiopolis
Athens (621), Greece

References:

Hardie, R.H.: 1962, Stars and Stellar Systems, Vol.II, Astronomical
   Techniques, ed. Hiltner, W.A., The University of Chicago Press, Chicago
Hopp, U., Witzigmann, S., Kiehl, M.: 1979. I.B.V.S. No. 1599
Kwee, K.K.: 1966, Bull. Astron. Inst. Neth. 18, 448 [BIBCODE 1966BAN....18..448K ]
Kwee, K.K., Van Woerden, H.: 1956, Bull. Astron. Inst. Neth. 12, 327 [BIBCODE 1956BAN....12..327K ]
Van't Veer, F.: 1973, Astron. and Astrophys. 26, 357 [BIBCODE 1973A&A....26..357V ]