On Long-baseline Amplitude Interferometers in Astronomical Applications

A generalized long-baseline amplitude interferometer which operates in pupil space is examined. The advantages of working in pupil space are considered by comparison with image space methods. In the absence of chromatic incoherence the pupil space interferometer gives immunity against guiding errors and arbitrarily good signal to noise ratios with arbitrarily large telescope pupils. Chromatic effects, when combined with random guiding errors, set an upper limit to the pupil size which may be used with a given bandwidth, but the pupil space design remains less sensitive to guiding errors than image space designs.