The hyperfine structure of 11 Os I-lines in the violet and ultraviolet spectral range was investigated by a digital recording Fabry Perot spectrometer. An enriched sample of Os189 was used in the hollow cathode light source. The recorded structures were analyzed on a computer. The quadrupole coupling constants of the states 5d66s25D2,5D3,5D4 and 5d76s5F5 or linear combinations of these coupling constants were deduced from the measurements. With these results the nuclear quadrupole moment of Os189 was determined to beQ(Os189)=(0.91 ± 0.10) · 10−24 cm2. This was done using the eigenfunctions ofGluck, Bordarier, Bauche andVan Kleef, which have been calculated for intermediate coupling considering configuration interaction.