COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 3156


                                        Konkoly Observatory
                                        Budapest
                                        15 March 1988

                                        HU ISSN 0374 - 0676


        NEW PHOTOELECTRIC TIMES OF MINIMA OF V839 OPHIUCHI


  V839 Oph is a W UMa-type variable which shows noticeable changes
in its light curves. These changes could arise from activity on the
surface of the common envelope or from some material surrounding the
system (Lafta and Grainger, 1985).

  During a program of photoelectric observations of eclipsing binary 
stars, the system was observed in two colours (B and V) on June 9-16,
1985. The observations were made with a 48-inch Cassegrain reflector
and a two beam multi-mode photometer (Goudis and Meaburn, 1973). The
two intermediate pass-band filters used were selected to be in close
accordance with the standard UBV colour system. BD+9 3589 and BD+9 3573
were used as comparison and check stars respectively.

  Five times of minima observed during this season were calculated
by the method of bisecting chords which connect the points of equal
magnitudes on the opposing branches near the minimum.



                      Table I

       HJD           E   O-C   Filter  Rem.

    2440000+
    6228.5744  14132.5  0.0354   B,V   MinII
    6229.3928  14134.5  0.0358   B,V   MinII
    6230.4152  14137    0.0357   B,V   MinI
    6231.4379  14139.5  0.0380   B,V   MinII
    6233.4817  14144.5  0.0348   B,V   MinII

   The successive columns of Table I contain the heliocentric time
of minimum, the number of cycles E, the difference O-C, the filter
used and remarks. The O-C values were computed according to the
ephemeris
                          
         MinI = JD Hel 2440448.4129 + 0.40899532 x E

which has been taken from the "General Catalogue of Variable Stars",
Vol. II, edited by Kholopov et al.(1985).
   A detailed analysis of the observations of V839 Oph will be given
elsewhere.





                       P.G. NIARCHOS

                       Section of Astrophysics,
                       Astronomy and Mechanics
                       Department of Physics
                       University of Athens
                       GR-157 83 Zografos
                       Athens, GREECE





References:

Goudis, C. and Meaburn, J.: 1973, Astrophys. Space Sci. 20, 149. [BIBCODE 1973Ap&SS..20..149G ]
Kholopov, P.N. et al.: General Catalogue of Variable Stars, Vol. II,
             "Nauka", 1985.
Lafta, S.J. and Grainger, J.F.: 1985, Astrophys. Space Sci. 114, 23. [BIBCODE 1985Ap&SS.114...23L ]