  This review attempts to place the observations of extragalactic planetary
nebulae in the context of galactic dynamics. From this point of view only the
radial velocities of the PNe are important. We have built a specialised
instrument to detect PNe in distant galaxies and measure their radial
velocities in one step. This is explained in some detail, along with classical
techniques for obtaining kinematic information. The review includes a vision of
possible future developments in the field.
