National Astronomical Observatory of Japan

Nobeyama Radio Observatory

Nobeyama 45-m Radio Telescope

What is the Nobeyama 45-m Radio Telescope?

The Nobeyama 45-m Radio Telescope, installed at Minamimakimura, Minamisaku, Nagano, boasts one of the world’s largest apertures for radio telescopes observing the radio waves known as “millimeter waves.” It has led Japanese radio astronomy since its completion in 1982. In particular, its research showing for the first time that a supermassive black hole exists in the center of a galaxy surprised the world.

Even today, more than 30 years since the start of observations, it is one of the world’s highest performance radio telescopes in the millimeter wavelengths around 3 millimeters. This shows how far the plan was ahead of its time. Technologies developed in the Nobeyama 45-m Radio Telescope are utilized in today’s telescopes such as ALMA.

Nobeyama 45-m Radio Telescope


Utilizing the high sensitivity and high resolution of the Nobeyama 45-m Radio Telescope, we conduct a wide range of observations, from Solar System bodies and planetary atmospheres to protogalaxies at the edge of the Universe. The Nobeyama 45-m Radio Telescope has many observation modes. It is excellent at capturing the emission lines from the molecular gases constituting celestial bodies and excels at observing the composition, mass, and movements of those gases.

We have discovered many interstellar molecules and elucidated how the chemical composition of interstellar gas evolves, clarified the structures of galaxies and the circumstances of star formation, and achieve advanced results in a wide range of astronomy research.


LocationNAOJ Nobeyama (Nobeyama, Minamimakimura, Minamisaku, Nagano, Japan)
Prime manufacturerMitsubishi Electric Corporation
Antenna systemBeam waveguide optics
Antenna diameter45 meters
Surface accuracy of the mirror0.1 millimeter
Frequency1 to 150 gigahertz
Angular resolution0.004° (80/20 vision in terms of eyesight)
CharacteristicsThe Nobeyama 45-m Radio Telescope is one of the world’s largest single dish radio telescopes in the 100 gigahertz band. Besides being large, it has a state-of-the-art receiver that makes full use of semiconductors and superconducting technology, and boasts high sensitivity with world class observational performance in the 100 gigahertz band.


1967The National Committee for Astronomy adopted a basic plan centered around a 45-m radio telescope.
1978Nobeyama Radio Observatory established. Antenna construction started.
1981Nobeyama 45-m Radio Telescope started test observations.
1982Common use began for the Nobeyama 45-m Radio Telescope.
2011Multi-beam receiver FOREST first-light.
2016Certified as an IEEE Milestone.

Main Research Results