The NPOI project was initiated by the United States Naval Observatory (USNO) in 1987. Lowell joined the project the following year when the USNO decided to build the NPOI at Anderson Mesa. The first phase of construction was completed in 1994, which allowed the interferometer to see its first fringes, or light combined from multiple sources, that year. The Navy began regular science operations in 1997. The NPOI has been continuously upgraded and expanded since then, and has been operational for a decade. The workings of NPOI as a classic interferometer, are described at Scholarpedia, and at the NPOI site.