Optical synthesis telescopes

A new type of optical/infra-red telescope is suggested, based on a combination of the principles of radio astronomical interferometric image synthesis and computational phase retrieval. Physical configurations, design principles, necessary technical developments, possible modes of operation and important possible uses of the telescope are discussed. The design philosophy is that it should not be necessary to maintain tighter mechanical tolerances than those required conventionally for radio telescopes. Because it is intended to realize milli-arc-second resolution, implying a telescope aperture of the order of 100 m, it is recognized that it is impractical to achieve optical tolerances, so that the adopted design principles should not rely on them. The design goals can be attained by relying on heterodyne detection followed by purely digital processing, thereby permitting usefulsignal-to-noise ratios to be conveniently obtained by multiplexing parallel channels with the aid of large-scale-integration techniques. Besides offering highly resolved images of many of the more important astrophysical objects, the telescope could be used for imaging certain types of space vehicles. The kind of telescope proposed herein could be usefully constructed either on the surface of the earth or outside the Earth’s atmosphere.