Inter-University Research Institute Corporation, National Institutes of Natural Sciences,
National Astronomical Observatory of Japan
Mitsubishi Electric Corporation
No. 3117

Nobeyama 45-m Radio Telescope Developed by the National AstronomicalObservatory of Japan and Mitsubishi Electric Recognized as"IEEE Milestone"
Has contributed greatly to advancement of radio astronomy since debuting
as the-world's largest millimeter-wave telescopeTOKYO, June 14, 2017 – National Astronomical Observatory of Japan (NAOJ) and Mitsubishi Electric
Corporation (TOKYO: 6503) announced today that the Nobeyama 45-m Radio Telescope has been certified
as an "IEEE Milestone" by the Institute of Electrical and Electronics Engineers (IEEE). The certification
recognizes the many technical difficulties that were overcome to develop the world's largest millimeter-wave
radio telescope at the time of its debut in 1982, leading to groundbreaking achievements such as thediscovery of a supermassive black hole while continuing to perform as a world-leading radio telescope to thepresent day.
This is the NAOJ’s first IEEE Milestone. The commemorative plaque presented by the IEEE will be exhibited at
the NAOJ’s Mitaka Campus, the Nobeyama Radio Observatory and Mitsubishi Electric Communication SystemsCenter.

In 1982, the Tokyo Astronomical Observatory
in collaboration with Mitsubishi Electric
Corporation completed the 45-m telescope as
the world’s largest antenna for millimeter-wave
radio astronomy. The 45-m telescope’s
innovative engineering contributed to theprogress of radio astronomy by enablinghigh-resolution and high-sensitivity
observations. Notable discoveries included newinterstellar molecules and a black hole.
IEEE Milestone commemorative plaqueThe history of the Nobeyama 45-m Radio Telescope dates back to 1967. Millimeter waves were an
unexplored field at the time, so there was a need to spectroscopically observe millimeter waves emitted fromvarious molecules in the universe to explore new fields, such as the process of star formation and thestructure of galaxies. The Nobeyama 45-m Radio Telescope was conceived as the world's largest telescopewith a 45-meter diameter at a time when the world's largest radio telescope had a diameter of 11 meters.
Radio astronomers at the NAOJ (then Tokyo Astronomical Observatory) and engineers at Mitsubishi Electric
conducted thorough discussions and studies on how to direct a large mechanical structure to a desired
direction without deforming. The result was a variety of technological breakthroughs, including a1/3

homologous design, master collimator and a method to suppress thermal deformation by covering thebackup structure with insulation panels. These now-indispensable technologies are used widely in large
telescopes and large antennas today.
After 35 years of operation, the Nobeyama 45-m Radio Telescope is still one of the world's top-performing
radio telescopes for observing millimeter waves of around 3 mm in wavelength, showing how advanced thetelescope’s design was at the time of conception.
The NAOJ designs and constructs large astronomical research facilities for open-use programs contributing
to further development of astronomy and society through sharing research results. Mitsubishi Electricdevelops advanced technology for the manufacture of large telescopes as scientific infrastructure that
contributes to the advancement of society, including the Japan Meteorological Agency 's Mount Fuji Radar
System (approved in 2000), KDDI’s Pacific Crossing TV Satellite Relay (certified in 2009), and the MU
radar together with Kyoto University (certified in 2015).
About IEEE and IEEE Milestone
The IEEE is the world’s largest technical profession organization in the fields of electricity, electronics,information and communications. It is headquartered in the United States and had more than 420,000
members in over 160 countries, including 14,266 members in Japan, at the end of 2016. The IEEE Milestone
program, founded in 1983 to honor historical achievements at least 25 years after their development,recognizes groundbreaking innovations in the fields of electricity, electronics, information andcommunications. The program raises awareness and appreciation of engineers by recognizing outstanding
technological achievements that have had at least a regional impact.
Nobeyama 45-m Radio Telescope Specifications
Installation

Nobeyama Radio Observatory

Antenna system

Beam waveguide optics

Antenna diameter

45 meters

Surface accuracy

0.1 millimeter

Frequency

1 to 150 Gigahertz

Angular resolution

0.004°

WeightApprox. 700 tons
https://www.nro.nao.ac.jp/en/

Reference URLs

http://www.nro.nao.ac.jp/~nro45mrt/html/index-e.html
http://www.MitsubishiElectric.com/bu/space/ground/optical/index.html

Comments on Certification
Masahiko Hayashi, Director General of NAOJ, said: “It is a great honor for the National Astronomical
Observatory of Japan to see the 45-m Radio Telescope at the Nobeyama Radio Observatory recognized as anIEEE Milestone. The 45-m Radio Telescope, Japan’s first large-scale telescope project, has madegroundbreaking achievements including the discovery of a supermassive black hole, and paved the way for
the Subaru Telescope and the Atacama Large Millimeter/submillimeter Array. I express my gratitude toeveryone who has supported us and I share this honor with them.”

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Masaki Sakuyama, President & CEO of Mitsubishi Electric, said: “We are honored and take great pride inthe 45-m Radio Telescope receiving a prestigious IEEE Milestone award. We deeply appreciate the National
Astronomical Observatory of Japan for giving us the opportunity to help develop and manufacture thishistoric telescope. Mitsubishi Electric is an environmentally advanced company that contributes tosustainability through technological innovations for safety, security and convenience.”
Inquiries
About NAOJ:
National Astronomical Observatory of Japan
Public Relations Center Public Relations Office
2-21-1 Osawa, Mitaka, Tokyo 181-8588, JAPAN
Phone: +81-422-34-3621 (Head: Dr. Yamaoka) / Fax: +81-422-34-3810
E-mail: hitoshi.yamaoka@nao.ac.jp
About Nobeyama 45-m Radio Telescope:
Nobeyama Radio Observatory462-2 Nobeyama, Minamimaki, Minamisaku, Nagano, 384-1305, JAPAN
Phone: +81-267-98-4355 (staff: Dr. Kinugasa) / Fax: +81-267-98-3579
E-mail: kinugasa.kenzo@nao.ac.jp
Mitsubishi Electric Corporation
Public Relations Division
2-7-3 Marunouchi, Chiyoda-ku, Tokyo 100-8310, Japan
Phone: +81-3-3218-2831 (staff: Niels Meinke) / Fax: +81-3-3218-2431
E-mail: Niels.Meinke@ah.MitsubishiElectric.co.jp

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