Speckle Image Reconstruction. Appendix 1.
STEWARD OBSERVATORY TUCSON ARIZ
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By adjusting the optical pathlengths of the MMT Multiple Mirror Telescopes telescopes, it is possible to make the MMT into a phased array with a 6.86 m baseline. A coherent, phased focus can be achieved with tilted focal planes if the tilt angle is chosen so that the internal phase differences exactly compensate the external phase differences. This amounts to a slight change in configuration such that the beams are brought together at f8.39 rather than the originally designed f9. We summarize experiments which have used the MMT subapertures as a phased array and as a coherent, phased telescope, and present a simple analysis of the tilted focal plane geometry for coherent observation. The phased operation of the MMT is important not only for obtaining high angular resolution, but also for obtaining the higher detection sensitivity which results from the better discrimination against the sky emission background for infrared diffraction limited images. Full-aperture six-beams, diffraction-limited results for the unresolved source Gamma Orinois, the well-known close binary Capella and the resolved red supergiant Betelgeuse, including a diffraction limited differential speckle image of the latter are presented.