The Palomar Testbed Interferometer (PTI) was a near-infrared, long-baseline stellar interferometer that was located at Palomar Observatory in California. First fringes were obtained in July 1995, and it was operated until December 2008.
PTI's development and early operations were carried out by the Jet Propulsion Laboratory (JPL), California Institute of Technology, with funding from NASA under its TOPS, ASEPS, and Origins programs, with additional funding from the JPL Director's Discretionary Fund and the JPL Director's Research and Development Fund. Subsequent science operations were carried out by the NASA Exoplanet Science Institute (NExScI), California Institute of Technology.
Additional information on PTI, including a publication list and access to PTI data, is available at the NExScI PTI site.