The Naval Prototype Optical Interferometer or NPOI is a telescope facility located on top of Anderson Mesa along Lake Mary Road, just south-east of Flagstaff, AZ. The NPOI is a joint project of the US Naval Observatory and the Naval Research Laboratory operating in conjunction with Lowell Observatory.
The NPOI is a series of mirrors laid out in a "Y" formation, with each arm measuring hundreds of feet in length. These mirrors each collect light, and send it to a combining lab, which will align the light frequencies from each of the siderostats, then transfer it into computerized data.