COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3177


                                                Konkoly Observatory
                                                Budapest
                                                18 April 1988

                                                HU ISSN 0374-0676


             PHOTOELECTRIC B AND V OBSERVATIONS OF W UMa

  Photoelectric observations of the short period eclipsing binary system W UMa,
discovered by G. Muller and P. Kempf at Potsdam in 1903, were carried out during
four nights between January 30 and March 4, 1987. A photometer equipped with an
unrefrigerated EMI 9781B photomultiplier tube and standard B, V filters has
been used, attached to the 32 cm f/16 Cassegrain telescope, located in Ljubljana,
Yugoslavia. The star SAO 27340 (HD 83564) was used as a comparison star.

  In the Figure 1, the light curves obtained in B and V colours, respectively,
are presented. The phases were calculated according to the light elements:
         
         Min. I = J.D. Hel. 2444986.3624 + 0.33363808d E

given by Hamzaoglu et. al. (1982)


                          [FIGURE 1]



  From this data times of minima have been calculated using the tracing paper
method.

         The minimum times are:

         Min. I  = JD (Hel) 2446826.3658
         Min. II = JD (Hel) 2446826.5349





                       A. DOLZAN

                       Zasavska 88
                       61231 Ljubljana
                       Yugoslavia


Reference :

Hamzaoglu, M., Hamzaoglu, E., and Eker, T., 1982, I.B.V.S. No. 2151.