1 Introduction

The orbital elements for double stars A 998, BU 1186, HU 442, BU 1125, STF 2275, HU 1290, HU 953, BU 984 have not been derived as yet. In spite of significant uncertainties in their distances, usual in the case of the visual measurements, the observed arcs allow a sufficiently reliable determination of their elliptical orbits.

The orbital elements are derived by using the procedure proposed by Popovic & Pavlovic (1995), the absolute magnitudes of the components, the masses and parallaxes are obtained by applying Angelov's (1993) relations, and the errors of the fitting parameters are obtained by using the Eichhorn & Xu algorithm (1990). The elements are given for the epoch J2000.0. All elements have been published in the "Information Circular 135 and 136, IAU, Comm. 26''.

The orbital elements and the corresponding astrophysical quantities are given in Table 1, the O-C measurements in Table 2. The authors of the orbits are given at the bottom of Table 1. The ephemeris are calculated for the next 10 years, beginning with 1999, the step length is one year. The final part contains the figures with the orbits.