THE HAYSTACK-MILLISTONE INTERFEROMETER SYSTEM.
MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
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The Haystack 120-ft antenna and the Millstone 84-ft antenna have been coupled together to form a radiometric interferometer. At 18-cm wavelength, which was chosen for a study of galactic OH emission, the interferometer has a minimum fringe spacing of 54 seconds of arc. The interferometer synthesizes a beam approximately equivalent to that of a 2000-ft parabolic antenna and can measure positions to a small fraction of the fringe spacing. The interferometer uses a digital correlator to analyze the fringe amplitude and phase as a function of frequency. This enables mapping of spectral features. The design and construction are described, as well as the theory and method of data reduction. A noise analysis shows that the threshold level could be reduced by using more complex processing techniques. It is shown that for radiometric studies many of the capabilities of a very large antenna can be synthesized, with smaller antennas and complex data-processing equipment taking the place of mechanical structure. Author
- Electrical and Electronic Equipment
- Test Facilities, Equipment and Methods