  The Narrabri intensity interferometer was successfully used until 1974 to
observe 32 stars, all brighter than B=+2.5, among which some were found to have
an angular diameter as small as 0.41+/-0.03 milli-arc-seconds (mas). The
technique was then abandoned in favor of Michelson interferometry. Here we
consider the technical feasibility and scientific potential of implementing
intensity interferometry on Imaging Air Cherenkov Telescope arrays. The
scientific motivations are varied, including stellar diameter measurements and
investigations of the circumstellar environment. Long baselines and short
wavelengths are easily accesible to this technique, making it uniquely suited
for some applications.
