Recent advances in detector technology as well as the launching of the International Ultraviolet Explorer (IUE) satellite have opened new spectral regions for extensive spectroscopic observation. A program to determine the feasibility of radial velocity measurement for binaries whose secondaries are of earlier spectral type has been initiated with the IUE satellite. It is expected that velocities with uncertainties as small as 2-5 km s−1 may be obtained for some stars. This observing program includes tau Per and other composite spectrum binaries as well as several early-type binaries.

For the past five years, a Reticon solid-state photodiode array detector has been used at the coudé focus of the 2.7 m McDonald Observatory reflector to obtain radial velocities of spectroscopic as well as short-period visual binaries. The high quantum efficiency, red sensitivity, and stability of this detector system permit velocities of high accuracy to be determined and previously unseen spectroscopic components to be detected.