COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                   Number 2099

                               Konkoly Observatory
                               Budapest
                               1982 March 4

                               HU ISSN 0374-0676


        PHOTOELECTRIC PHOTOMETRY OF NN CEPHEI


  NN Cephei (BD + 61d2384 = HD 217796) is catalogued as RR?
in the Second Supplement to the Third Edition of the General
Catalogue of Variable Stars (1974). The eclipsing character of
the system was firstly announced by Figer and Rolland (1977).
They observed the system visually and gave the light elements
as follows:

        Min I = JD Hel 24 42 959.57 + 2.058d.E,
                                +-7     +-2

and suggested that the shape of the mean light curve is of
 Beta Lyrae type.
  The first photoelectric minima, light elements and light
curves were published by Gudur and Gulmen (1980). The new light
elements were found as,

        Hel Min JD = 24 44 507.4033 + 2.058305d.E
                                +-4        +-5


However, the light curve was not complete. For this reason we
continued to observe the system with the same telescope and
equipment at the Ege University Observatory. The comparison and
check stars are. taken to be the same stars
(BD + 61d2388, BD + 61d2385) with the previous observations.
The system is observed totally on 30 nights from July 1979 to
October 1981, and 1177 and 1058 individual points were obtained
in B and V colours, respectively. The extinction coefficients in
separate colours for each night were calculated from the 
observations of comparison star using the conventional method,
then all the differential observations (variable minus comparison)
were corrected for the differential extinction.
  The light and colour curves of the system are presented in
Figure 1, The new photoelectric minima obtained in 1981 are
given in Table I.


                       [FIGURE 1]

                Table I
         Times of minima of NN Cep
--------------------------------------
Hel Min   JD      Min   Filter   O-C
--------------------------------------
24  44  824.3814    I    B,V   -0.0009
        827.467    II     "    -0.003
        859.3742    I     "    +0.0007
        893.336    II     "    +0.001
--------------------------------------


The phases in Figure 1 and the O-C values in Table I were
calculated by using the light elements given by Gudur and Gulmen
(1980). The accuracy of these light elements are confirmed by
the small O-C values in Table I. The light curves show a 
sinusoidal shape it we do not consider the eclipses. This is a
very good example of the proximity effects. It is also seen that
the light curves are of Algol type. There are no other complications 
in the light curves. The solutions are in progress.
  This project is partly supported by the Turkish Scientific
and Technical Research Council.

           O. GULMEN, N. GUDUR and C. SEZER

           Ege University Observatory
           Boronova - Izmir - Turkey


References:
Figer, A. and Rolland, R.: 1977, IBVS No. 1231.
Gudur, N. and Gulmen, O.: 1980, IBVS No. 1881.