  Since the Bosscha Observatory was established in 1923 researches on visual
binary stars played an important role in astronomical studies in Indonesia. The
visual binary of WDS 17190-3459 = MLO 4AB = HD156384 = HIP84709 was extensively
observed at our observatory and other observatories. This system has already
passed periastron three times since observed in the end of year 1876. The
observation data is more than enough to construct an orbit. By using
Thiele-Innes method we computed the orbit, and physical parameters are
determined by using mass-luminosity relation. The result is presented in the
table. Orbital Parameters: e = 0.578, P = 42.3 years, T = 1974.9, i = 132
o.7,{\omega} = 247o.5, {\Omega} = 318o.1, a = 1".713, mu = 8 o.51/years
Physical Parameters:p = 0".134, Mbol1 = 6.7, Mbol2 = 7.4, M1 = 0.6 Mo, M2 = 0.5
Mo, q = 0.863. At time being there are several new methods for determining the
orbit; for example the method of Gauss done by S\"oderhjelm (1999) for
calculating the orbit of the same stars WDS 17190-3459. Our results are
relatively same.
