COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                              Number 2934

                                                         Konkoly Observatory
                                                         Budapest
                                                         17 September 1986

                                                         HU ISSN 0374 - 0676


     PHOTOELECTRIC OBSERVATION OF THE ECLIPSING BINARY u HERCULIS

 The eclipsing binary u Her (68 Her, HR6431, HD 156 633, BD+33d 2864,
GC23 359, SAO 65 913) was detected as an optical variable in 1869 (Schmidt,
1869). In 1903 it was found to be a spectroscopic binary (Frost and Adams,
1903), and in 1908 an eclipsing variable with a period of 2.051 days. The
first set of photoelectric light curves for u Her was obtained in 1922 (Baker,
1926).
   This eclipsing binary was observed photoelectrically with the 40 cm
Cassegrain telescope of Al-Battani Observatory (Iraq, Tarmiya, latitude
+33d47'32" N, longitude 44d28'6 E) during 26 nights between May-September
1985.

                          [FIGURE 1]

     Figure 1.  Light curve of the eclipsing binary u Her


   The photometer was furnished with an uncooled 1P21 photomultiplier tube
and UBV filters in close accordance with the standard Johnson's filters
(Kadourie et al., 1986). The observations were only made in B and V lights.
The star 72 Her (HD 157 214 or SAO 65 963) was used as a comparison star, and
the check star was HD 158 261 or SAO 66 054. The estimated uncertainties for a
single observation are of the order of +0.05 in V and +0.06 in B. The extinction 
coefficients have been calculated from the comparison star observations.
   A total of 598 observations were obtained in each filter which are presented 
in Figure 1, where the phases are calculated according to Koch and Pfeiffer
(1977) :

       Min.I. (hel.) = 240 5830.033 + 2.051 02 70 d E

   In the following table the observed heliocentric times of minima with
the O-C values from the above ephemeris are presented.

        Type          J.D.           O-C

        Min. I   244 6315.24147     -0.0104
        Min. II  244 6314.22640      0.0

   The strong asymmetry in the secondary minimum provides strong evidence
for the reflection effect and indicates the existence of a gaseous stream
in the system (Al-Naimiy and Budding, 1977). The analysis of the light
curves will be published elsewhere.


                  S.R. JABBAR, N.L. JABIR, H.A. FLEYEH, Q.S. MAJEED

                        Space and Astronomy Research Centre
                           Scientific Research Council
                            Jadiriyah, Baghdad, Iraq



References:

Al-Naimiy, H.M., and Budding, E.: 1977, Astrophys. Space Sci., 51, 265. [BIBCODE 1977Ap&SS..51..265A ] 
Baker, R.H.: 1926, Lick Obs. Bull., 12, No. 738. [BIBCODE 1926LicOB..12..130B ]
Frost, E.B., and Adams, W.S.: 1903, Astrophys. J., 17, 381. [BIBCODE 1903ApJ....17..381F ]
Kadourie, T.H., Al-Roubaia, A.H., and Mutter, A.A.: 1986, Journal of Space
   and Astronomy Research, 3, 13.
Koch, R.H., and Pfeiffer, R.J.: 1977, Inf. Bull. Var. Stars, No. 1326.
Schmidt, J.: 1869, Astron. Nachr., 74, 230. [BIBCODE 1869AN.....74..229S ]