WIDE-FIELD PERFORMANCE OF A PHASED-ARRAY TELESCOPE

A phased array telescope is an array of optical telescopes whose image s are coherently combined so as to achieve the resolution of a single but much larger telescope, Phased array telescopes deliver the resolut ion of very large telescopes without the difficulties and expenses ass ociated with very large optics. To achieve this resolution, a wide fie ld of view (FOV) phased array imaging system must accurately control p hase and must superimpose the images from all telescopes to within a f raction of a resolution element over the whole FOV simultaneously. We built a test bed called the Multipurpose Multiple Telescope Testbed (M MTT). It consists of four 20-cm-aperture telescopes phased together wi th a +/- 15-arcmin FOV. It has no mount and is designed for laboratory use only, We present a brief description of the MMTT and then describ e performance tests and results. The phasing and image superpositionin g accuracy of the array were measured using star tests. Several of the resulting point spread functions were recorded simultaneously at thre e different field angles to determine the wide FOV performance of this phased array. These images were analyzed and compared to theoretical predictions.