An infrared spatial interferometer has been developed to extend the spatial resolution of astronomical observations beyond the diffraction limits of existing telescopes. It is the first such instrument to measure the angular diameters and shapes of circumstellar shells at wavelengths from 2 to 20 AM. As a result, the angular resolution of routine telescopic observations at 10 µm has been extended from ~1 arcsec to ~0.1 arcsec even though observations are often obtained in ~3 arcsec conditions of atmospheric "seeing."
D. W. McCarthy,
F. J. Low,
"Design and Operation of an Infrared Spatial Interferometer," Optical Engineering 16(6), 166569 (1 December 1977). https://doi.org/10.1117/12.7972163