Nobeyama Radio Observatory (NRO) is the radio astronomy facility of the National Astronomical Observatory of Japan, founded in 1978 and located 120 km west of Tokyo at Minamisaku, Nagano. It has played a pioneering role in millimeter wave astronomy through use of a 45-meter dish and the Nobeyama Millimeter Array – an aperture-synthesis telescope consisting of six 10-meter antenna movable along two intersecting 500-meter baselines. These instruments are the world's largest at millimeter wavelengths and work in conjunction, locally as the 7-element RAINBOW interferometer and globally as part of the VLBI Space Observatory Program. NRO is also home to the Nobeyama Radioheliograph, which investigates solar radio emission using 84 dishes of 0.8-meter aperture in a T-shaped array.