Published online by Cambridge University Press: 12 April 2016
Interferometric arrays possessing sub-milliarcsecond resolution are either about to be fully scientifically productive, as in the case of the Sydney University Stellar Interferometer, or are under various stages of planning and development. The 1990’s will thus witness a hundred–fold gain in resolution over speckle interferometry at the largest telescopes and 5,000 times the resolution of classical direct imaging. Where speckle interferometry can now resolve binary stars with periods of 1 to 2 years, interferometric arrays with baselines of hundreds of meters will resolve binaries with periods of a few hours. Arrays will resolve the majority of the known spectroscopic binaries, providing a substantial increase in the quantity and quality of stellar mass determinations. Surveys for new binaries among the field stars and other restricted samples will be accomplished with unprecedented completeness. The remarkable enhancement in resolution we are about to witness from facilities like SUSI and our own proposed CHARA Array will quite literally revolutionize the field of double and multiple star research.