Measurements of expansion velocities in planetary nebulae

Abstract

We have used a scanning Fabry–Perot interferometer on the 1.5-m flux collector, Tenerife, to obtain [O III] λ 5007 Å emission line profiles at the centres of 33 planetary nebulae. The observations were made at a resolution of ~ 3 km s–1 through entrance apertures of 5, 10 or 18 arcsec diameter.