  We discuss the design, construction, and operation of a new intensity
interferometer, based on the campus of Southern Connecticut State University in
New Haven, Connecticut. While this paper will focus on observations taken with
an original two-telescope configuration, the current instrumentation consists
of three portable 0.6-m Dobsonian telescopes with single-photon avalanche diode
(SPAD) detectors located at the Newtonian focus of each telescope. Photons
detected at each station are time-stamped and read out with timing correlators
that can give cross-correlations in timing to a precision of 48 ps. We detail
our observations to date with the system, which has now been successfully used
at our university in 16 nights of observing. Components of the instrument were
also deployed on one occasion at Lowell Observatory, where the Perkins and Hall
telescopes were made to function as an intensity interferometer. We
characterize the performance of the instrument in detail. In total, the
observations indicate the detection of a correlation peak at the level of
6.76-sigma when observing unresolved stars, and consistency with partial or no
detection when observing at a baseline sufficient to resolve the star. Using
these measurements we conclude that the angular diameter of Arcturus is larger
than 15 mas, and that of Vega is between 0.8 and 17 mas. While the
uncertainties are large at this point, both results are consistent with
measures from amplitude-based long baseline optical interferometers.

Instrumentation and Methods for Astrophysics;Solar and Stellar Astrophysics