Welcome to the home page of the Navy Prototype Optical Interferometer
Welcome to the home page of the Navy Prototype Optical Interferometer, NPOI. At this site you can learn about
what the NPOI is and how it is used,
how the NPOI has developed over time, and
its contributions to research. You can find out
what's new at the NPOI, and you can
take an online tour of the interferometer.
NPOI is a specialized astronomical telescope called an interferometer. Instead of a single telescope,
an array of six mirrors spaced tens of meters apart precisely direct beams of light from a star to a point.
Extraordinary image detail can be derived from the resulting data.
NPOI can record images of stars and optically separate distant pairs of stars so close together that
they appear as a single star in even the largest conventional telescopes. NPOI has the ability to measure
the precise relative positions of stars across the sky which the Naval Observatory uses as a reference system
for the determination of positions on earth and in space and for monitoring time keeping. Currently operating
at about one-fourth of its designed capability, when finished the interferometer will span the distance of
over four football field lengths, 430 meters.
NPOI is a collaborative effort between the U.S. Naval Observatory,
the Naval Research Laboratory, and
Lowell Observatory with construction beginning in 1992.
It is located about 15 miles southeast of Flagstaff Arizona on the Lowell Observatory observing site within the Coconino National Forest.