Abstract

A space telescope produces a diffraction-limited point spread function (PSF) with ~84% of the energy confined to the central peak. Imaging arrays generally produce asymmetric PSF with less centrally concentrated energy. This effect tends to degrade sensitivity when sky background is taken into account. Thus resolution goals are better met by highly thinned arrays and sensitivity goals by highly filled arrays. For phased arrays, fill factor breaks the quadratic relationship between resolution and sensitivity characteristic of monoliths, and it is possible to choose configurations in which an increased collecting area produces gains in resolution and sensitivity at predetermined levels, a desirable feature for modular configurations. We have also examined the desirability of heterodyne and speckle imaging vs direct imaging. While both heterodyne and speckle imaging produce relaxed telescope tolerances, the loss in sensitivity associated with heterodyne and speckle imaging does not justify their use.

© 1986 Optical Society of America