COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 1881

                                   Konkoly Observatory
                                   Budapest
                                   1980 December 8

                                   HU ISSN 0374-0676



         THE NEW PHOTOELECTRIC EPHEMERIS AND
             LIGHT CURVES OF NN CEPHEI



NN Cephei was announced as RR ? in the Second Supplement to
the Third Edition of the General Catalogue of Variable Stars
(1974) and a Beta Lyrae type eclipsing binary by Figer and
Rolland ( 1977).
The system was observed photoelectrically at the Ege University
Observatory on 21 nights between July 1979 and October 1980.
The observations were made in yellow and blue colours with the
48 cm Cassegrain telescope equipped with an unrefrigerated
EMI 9781 A photomultiplier tube and Johnson's standard B, V
filters. A total of 740 and 624 observational points were obtained 
in B and V colour, respectively. BD +61d2388 was used as comparison 
throughout the observing period. The nonvariability of
it was checked with BD +61d2385. The extinction coefficients in
separate colours for each night were calculated from the observations 
of comparison star using the conventional method;
then, all of the differential observations were corrected for
differential extinction.
Three primary and four secondary minimum given in the following 
table were obtained.

              Times of minima of NN Cep
         Hel.Min.J.D. Filter      Min.    O-C
         2444086.4796    B,V      II    -0.0003
             438.4512     "       II     0.0011
             474.4717     "        I     0.0013
             504.3151     "       II    -0.0007
             506.3741     "       II     0.0000
             507.4026     "        I    -0.0007
             511.5194     "        I    -0.0005

New light elements are determined using the above photoelectric
minima by the method of least squares as,

       Hel.Min.J.D.=2444507.4033+ 2.058305d E.
                             +-4       +-5

The light and colour curves of the system are presented in the
Figure where the magnitude differences between the variable an
comparison stars have been plotted against the phases.

                       [FIGURE 1]


The phases in the Figure and the O-C values in the Table were
calculated with the new light elements. The light curves show
that the system is a beta Lyrae type eclipsing binary. As it will
be seen from the light curves there exist some complications on
the shoulders of minima, particularly in B colour. The system
varies about 0.414mag and 0.379m at the primary, 0.338m and 0.321m at
the secondary minimum in blue and yellow light, respectively.
The solutions of light curves will be published elsewhere.



                  NECDET GUDUR, OMUR GULMEN
                  Ege University Observatory
                  P.K. 21, Bornova-Izmir, Turkey
Reference:
Figer, A. and Rolland, R. 1977, I.B.V.S., No. 1231