Interferometric observations of the ring nebula NGC 6888 in the (O3)-line

The kinematics of the ring nebula NGC 6888 in O3 5007 A line has been investigated with a Fabry-Perot interferometer and two-stage image converter combined with the 125- and 60-cm telescopes spatial resolution was 10''-12'' and 18''-24'' respectively, spectral resolution - ≅ 15 km/s). The line profiles in 80 locations all over the nebula have been obtained showing three velocity components emitted by ambient H 2 regions and by the two sides of a thin expanding shell. The obtained O 3 radial velocity field have been used for reconstruction both of spatial geometry and expansion velocity of the shell. A model of prolate ellipsoid inclined to the plane of the sky by 20-40 deg and with the mean expansion velocity 88 +- 12 km/s has been found to fit the observational data best