COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1316

                                  Konkoly Observatory
                                  Budapest
                                  1977 August 4




            PHOTOELECTRIC MINIMA OF W UMa



    V photoelectric observations were carried out with a 21 cm
reflector at Skibotn on three nights in January and February
1977. A chopping photometer (Myrabo, 1977) was used to eliminate
the variation of the sky brightness caused by the aurora (Skibotn:
latitude 69d22'). The photometer was furnished with an EMI 9601 A
photomultiplier tube and Schott filter GG 14. BD +56d 1399 was
used as comparison star. The times of the minima are determined
by the least squares method described by Kwee and van Woerden:

    Minimum        J.D. Hel.    Phase interval
      II       2443 155.5246+-0.0004  0.12
      II            157.1926+-0.0004  0.12
       I            183.3858+-0.0003  0.10

    The measurements were part of an investigation of photometric 
observations of stars in the auroral zone. During 1977 a
new 50.8 cm telescope with a high-speed photometer will be 
installed. The long nights in winter at this high latitude where
most of the sky is cirkumpolar favour variable star observations.






   J. BONES                    H.K. MYRABO
   Institute of Mathematical   Norwegian Defence Research
   and Physical Sciences,      Establishment, Division for
   University of Tromso,       Physics, Kjeller,
   Norway                      Norway

Reference:
Myrabo, H.K. 1977, On stellar photometry in the auroral zone,
          The Auroral Observatory, Tromso, Report No. 44-77