Space

Anderson Mesa

The Naval Prototype Optical Interferometer (NPOI), located on Anderson Mesa near Flagstaff, AZ, is the largest operating optical telescope in the world. Located on Lowell Observatory's dark sky site at Anderson Mesa, the Mesa is southeast of Flagstaff, Arizona, approximately 15 miles from the edge of the town. The NPOI is a Y configuration of optical sidereostats. The inner fixed stations are used for astrometry while stations on the outer arms, out to an eventual separation of more than 300 m, are used for imaging stars. The stations are connected by vacuum beam lines. Fast delay lines in the main control building and long delay lines outside are used to adjust the optical phases to allow coherent combinations of up to six sidereostats. Used for astrometry and astronomical imaging, the NPOI is a distributed aperture optical telescope. It is operated for astrometry by the U.S. Naval Observatory. Research into optical imaging and astronomical research is conducted by NRL.

Funding for the Navy Prototype Optical Interferometer (NPOI) was initiated by the Oceanographer of the Navy and the Office of Naval Research in 1989. Design work began on all phases of the project. After approximately a year and a half, the initial phase of construction was completed in early 1994. This included the concrete piers to hold the siderostats, beam compressors, elevator cans and center feed cans for the imaging and astrometric arrays, the control and lab buildings and the astrometric huts. The east arm feed pipe installation was completed by December 1998.