The Navy Precision Optical Interferometer (NPOI) is an American
astronomical interferometer, with the world's largest baselines, operated by the
Naval Observatory Flagstaff Station (NOFS) in collaboration with the
Naval Research Laboratory
The United States Naval Research Laboratory (NRL) is the corporate research laboratory for the United States Navy and the United States Marine Corps. It was founded in 1923 and conducts basic scientific research, applied research, technological ...
(NRL) and
Lowell Observatory
Lowell Observatory is an astronomical observatory in Flagstaff, Arizona, United States. Lowell Observatory was established in 1894, placing it among the oldest observatories in the United States, and was designated a National Historic Landmark ...
. The NPOI primarily produces space imagery and astrometry, the latter a major component required for the safe position and navigation of all manner of vehicles for the DoD. The facility is located at Lowell's
Anderson Mesa Station on
Anderson Mesa
Anderson Mesa (Navajo: Hosh Dikʼání) is approximately five mesas long, located 20 miles southeast of Flagstaff, Arizona, United States, east of Lake Mary and north of Mormon Lake, in Coconino County.
This mesa landform, with an elevation bet ...
about southeast of
Flagstaff, Arizona
Flagstaff ( ) is a city in, and the county seat of, Coconino County in northern Arizona, in the southwestern United States. In 2019, the city's estimated population was 75,038. Flagstaff's combined metropolitan area has an estimated population ...
(US). Until November 2011, the facility was known as the Navy Prototype Optical Interferometer (NPOI). Subsequently, the instrument was temporarily renamed the Navy Optical Interferometer, and now permanently, the Kenneth J. Johnston Navy Precision Optical Interferometer (NPOI) – reflecting both the operational maturity of the facility, and paying tribute to its principal driver and retired founder, Kenneth J. Johnston.
The NPOI project was initiated by the