About Us


NAOJ is a Japanese astronomy research institute with a global reputation. It explores the mysteries of the Universe using all sorts of instruments, ranging from telescopes and satellites that can measure visible light, radio waves, and gravitational waves from celestial objects to supercomputers that allow for theoretical studies. The mission of the Public Relation Center is to provide the public with timely and accessible information about what is going on at the forefront of astronomy research.

However, our activities as a “window into the Universe” are not limited to keeping the public better informed about the latest knowledge and findings on astronomy; we are also involved in ephemeris computation, which is closely related to everyday life, such as identifying on what date vernal and autumnal equinoxes occur and at what time the Sun rises and sets. Providing information about popular astronomical events, such as solar eclipses and comets, also comprises a major part of our activities. To make everyone feel “astronomy is really fun,” we aim to keep providing high-quality science entertainment, especially by allowing for everyday free public access to our facilities and by disseminating information through our webpage, videos, and printed materials.

Director of the Public Relations Center: Hitoshi Yamaoka


1994Public Information Office founded
1995NAOJ website launched
April 1996Stargazing parties using the 50-cm Telescope for Public Outreach started
June 1998Public Information Office, New Objects Information Office, and Ephemeris Computation Office combined to form the Public Relations Center
July 2000Mitaka Campus Visitors’ Area opened
April 2004Library Unit and Public Relations Unit added to the Public Relations Center
2011Repsold Transit Instrument registered as an important cultural property
2014Office for Astronomy Outreach added to the Public Relations Center
April 2019Spectrum Management Office added to the Public Relations Center
April 2020Ishigakijima Astronomical Observatory added to the Public Relations Center
April 2022Time Keeping Office added to the Public Relations Center

Public Relations Office

“A New View of the Universe” at Your Finger Tips

Head: Hitoshi Yamaoka

“A New View of the Universe” at Your Finger Tips

There are probably people who, when they hear the word “astronomy,” think it has nothing to do with them.

But that’s not the case.

While walking a moonlit road at night, you might ponder how the Moon was formed long ago. Eventually, all the stars that emit light die, and the records of these giant explosions are preserved in the documents studied in classical literature classes. The topic of astronomy crops up in an array of places.

The Public Relations Office delivers the latest research results obtained at NAOJ observational and research facilities, as well as various topics related to astronomy, to everyone in an easy-to-understand format. We employ dynamic media, namely: press releases, web releases, email news, and social media. We also conduct the production of explanatory videos, live-relays of lectures, and a variety of other events and information distribution in cooperation with the Outreach and Education Office and the Publications Office.

The goal of the Public Relations Office is to connect you to Astronomy.

Head of the Public Relations Office: Hitoshi Yamaoka


Internet Information Distribution

We manage the NAOJ website and continue stable, regular information-distribution. We also issue email magazines from time to time.

Press Releases

We release press releases and hold press conferences regarding NAOJ research results, etc.

Internet Live-Relays, Video Production

We broadcast lectures and notable heavenly phenomena, such as solar and lunar eclipses, live via the internet. We also produce videos.

Citizen Astronomy

By using data obtained from the observation facilities of NAOJ, such as the Subaru Telescope, we aim to bridge the gap between the public and researchers through research projects in which citizens can participate.

International Outreach

We disseminate information through press releases in English, and host booths at international meetings to build relationships with overseas journalists.

Outreach and Education Office

Making Astronomy Accessible to Everyone

Head: Tomofumi Umemoto

Making Astronomy Accessible to Everyone

Astronomy is one of the oldest disciplines and is sometimes referred to as “a science for everyone.” The Outreach and Education Office engages in astronomy outreach and education in cooperation with partners and interested parties both inside and outside NAOJ.

The matters we handle include: (1) managing public visits to Mitaka Campus (including regular stargazing parties and 4D2U Dome Theater screenings); (2) providing reference services, such as through the telephone inquiries line; (3) leading outreach initiatives going out to towns and schools; (4) organizing nationwide campaigns in cooperation with other astronomy and space-related organizations and; (5) independently developing and distributing posters, astronomy-related products, movies, and software, in addition to conducting activities to make NAOJ more widely known as an open research institute.

We aim to make astronomy accessible to everyone through communication designed to meet the needs of different audiences, in order to make each and every person happy through astronomy and education.

Head of the Outreach and Education Office: Tomofumi Umemoto


Department of Public Visits

The Outreach and Education Office conducts tours and special events at Mitaka Campus, which is the open research facility where the headquarters of NAOJ is located. See more

Inquires Department

The Outreach and Education Office answers questions related to astronomy and space from everyone, offering information to strengthen interest and understanding in astronomy. See more

Department of Events and Education

The Outreach and Education Office plans and carries out a wide range of events for the purposes of astronomy outreach and education. See more

Department of Content Development

In the Outreach and Education Office, we publish web content, including introductions of the outreach and education activities occurring in each department and reference material for enrich the experience and understanding of astronomical phenomena. We also work on producing printed matter, teaching materials, etc. See more

Spectrum Management Office

Protection of the Environment for Radio Astronomy Observations

Head: Masaaki Hiramatsu

Protecting the Environment for Astronomy Observations

Astronomy seeks to understand the characteristics of celestial bodies by catching their very weak light and radio waves coming to the Earth from far away in the Universe. Strong artificial light and radio waves are threats to astronomical observations. The mission of the Spectrum Management Office is to protect an environment conducive to astronomical observation by reducing the light and radio waves that impede the observations.

Our everyday devices emit radio waves that are "too bright" for radio telescopes. If you put your cell phone on the Moon, it would be one of the 10 strongest radio sources in the entire sky. To insure that radio waves users do not interfere with each other, rules are established in Japan by the Ministry of Internal Affairs and Communications (MIC), and internationally by the International Telecommunication Union (ITU). The Spectrum Management Office, representing astronomers in Japan, attends the meetings for making these regulations, and negotiates with other radio wave users, so that we can protect the environment for astronomy observations.

In addition, “satellite mega-constellations,” communication networks comprised of many satellites, are becoming new threats to astronomy. The satellites reflect the sunlight, which can be bright enough to impede astronomy observations. Assessing the impact and considering international countermeasures is also an issue for the future.

Head of the Spectrum Management OfficeMasaaki Hiramatsu


Conferences and Negotiations

We attend the meetings and conferences held by the MIC and ITU, and negotiate with other radio wave users to ensure that the operation of radio wave emitting devices does not negatively impact radio astronomy observations.

Investigation and Research

We investigate and research the effects of satellites that shine brightly by reflecting sunlight, and city lights to optical/infrared astronomy observation, and then work to protect the environments for astronomy.

Ephemeris Computation Office

Setting the Japanese Calendar

Head: Masato Katayama

Setting the Japanese Calendar

The most important role of the Ephemeris Computation Office is to publish the Calendar and Ephemeris, which is one of NAOJ’s raisons d’être. To this end, we predict various heavenly phenomena, first and foremost the apparent positions of the Sun, Moon, and planets; but also the Solar Terms, including the vernal and autumnal equinoxes; sunrise and sunset times; moonrise and moonset times; solar eclipses, lunar eclipses, and the transits of planets across the solar disk. Because there is great interest in calendrical information closely related to everyday life, this material is always made readily available through the Rika Nenpyo (Chronological Scientific Tables), the Ephemeris Computation Office website, etc.

In addition, we are making the important historical documents (currently Japanese only) in the possession of NAOJ accessible to the Public through cooperation with the Library.

Head of the Ephemeris Computation Office: Masato Katayama


Publication of the Calendar and Ephemeris

We publish information about various heavenly phenomena, such as the apparent positions of the Sun, Moon, and planets.

Release of the Reki Yoko

Particularly important information from the calendar and ephemeris is selected, and an outline of next year’s calendar is published in the first official gazette in February each year.

Compilation of the Calendrical Section of the Rika Nenpyo

As the most trusted “handbook of natural sciences” in Japan, the Rika Nenpyo, with its more than 90 years of history, is published through cooperation with numerous research institutes.

Library Unit

A Hub Library for Astronomy Research in Japan

Head: Iori Koshihara

A Hub Library for Astronomy Research in Japan

We collect, curate, and preserve books, magazines, audiovisual materials, microfilm, and various other technical materials on astronomy, space-science, and related fields from both inside and outside of Japan. We also have general books. These references cover a wide range from the latest up-to-date scientific journals to important documents from the Edo Era.

Reading rooms are located on the 1st and 2nd floors of the South Building. You can examine our books at your leisure in these quiet rooms. The primary users are NAOJ members, collaborators, and students. But on weekdays (excluding national holidays), the library is also open to members of other institutions and the general public. In addition, cooperating with the libraries in NAOJ observatories scattered across Japan, we loan materials to libraries at universities and institutes throughout the country, and mail photocopies (for a fee) to people who cannot come to a library. We also hold regular exhibitions of important historical documents at the Observatory History Museum in combination with the Ephemeris Computation Office.

Head of the Library Unit: Iori Koshihara


Storing Domestic and International Books on Astronomy and Related Fields

Opening the Library to the General Public

On weekdays, members of the public are free to use the library.

Preservation and Exhibition of Important Historical Documents

We store about 3000 books, including, Japanese and Chinese books especially those preserved by the Tenmonkata (Astronomer for the Edo Shogunate), almanacs, and occidental books.

Digital Journals for use by NAOJ Researchers

We offer more than 5000 digital journal titles centered on astronomy, space-sciences, and related fields.

Publications Office

We introduce NAOJ through easy to understand publications.

Head: Hitoshi Yamaoka

Providing Up-to-date Information about NAOJ

What is NAOJ, and what does it do? NAOJ’s major mission is not only to support its astronomers to pursue their own research, but also to provide astronomers around the world with access to telescopes, supercomputers, and other newly developed instruments. Another of NAOJ’s major activities is to show everyone how fun and interesting astronomy can be. To make such efforts of NAOJ more widely known to the public, the Publications Office issues annual reports and NAOJ News on a regular basis. We are also involved in creating a pamphlet that explains details about NAOJ, and leaflets for public visits. We strive to provide NAOJ’s up-to-date information through various media such as e-books and videos as well as printed media.

Head of the Publications Office: Hitoshi Yamaoka


Issuing the “Annual Report of NAOJ” and “Publications of NAOJ”

We produce the “Annual Report of NAOJ” and “Publications of NAOJ” as needed.


Monthly issues introduce NAOJ research results and topics.


We update the Japanese pamphlet annually and the English pamphlet every 2 years.

Other Printed Materials

We produce calendars, posters, leaflets, and other assorted printed materials for public relations /outreach and education.

Office for Astronomy Outreach

Astronomy for Everyone - In Cooperation with the IAU -

Head: Lina Canas

Astronomy for Everyone! – Building Bridges through Access, Communication, and International Cooperation

The IAU Office for Astronomy Outreach (OAO) was established in 2012, as a legacy of the International Year of Astronomy (IYA2009) and is a joint project of the International Astronomical Union (IAU) and the National Astronomical Observatory of Japan (NAOJ), under the auspices of the National Institutes of Natural Sciences (NINS) of Japan. The office is based in Tokyo, at the NAOJ Mitaka Campus.

The mission of the OAO is to engage the public in astronomy through access to astronomical information and communication of the science of astronomy. This is implemented through a network of National Outreach Coordinators (NOCs) and the international engagement initiatives with the public, encouraging active communication of science through public engagement, professional-amateur relations, and citizen science activities.

The work of the OAO is about building bridges with the global astronomy community of amateur astronomers, outreach practitioners, educators, communicators, and the public, and through international collaboration, to make the science of astronomy accessible to all.

Head of the Office for Astronomy Outreach: Lina Canas


Connecting Countries Through a Network of Outreach Coordinators

We manage the international network of National Outreach Coordinators (NOCs) present in over 120 countries and regions, is a network composed by some of the most active and driven professionals making a difference in astronomy around the world.

Publishing a Journal for Astronomy Communicators

We publish the “Communicating Astronomy with the Public Journal” a peer-reviewed journal focused on astronomy outreach, public engagement, and science communication twice a year.

Making Astronomy Materials Accessible in Many Languages

The Astronomy Translation Network is a global volunteer network that translates astronomy materials into various languages. We now have about 400 volunteers working in several groups to translate each language.

Coordinating Large Scale International Outreach Initiatives

The Outreach Global Projects are annual international outreach activities officially endorsed by the IAU. These activities are generally celebrated around particular events and include Dark and Quiet Skies Awareness, Women and Girls in Astronomy, 100 Hours of Astronomy and Telescopes for All.

Informing and Connecting People Online

Twice a month we publish the “IAU Astronomy Outreach Newsletter” that delivers the latest information on astronomy outreach, public engagement, and communication to the international astronomy community.
IAU Astronomy Outreach Newsletter

To interact directly with our community around the world we stay connected through Facebook, Twitter and Email answering questions from the community.
Astronomy for the Public

Time Keeping Office

Keeping the Japanese Time

Head: Tetsuharu Fuse

Keeping the Japanese Time

Japan Central Standard Time is the basis for the time we use in everyday life. It is a legal responsibility for NAOJ to accurately determine this time and communicate it to society at large. Currently, NAOJ maintains and disseminates Japan Central Standard Time as a national duty. We also serve as one of the Japanese representative institutes in this field, contributing to the international time-comparison network, the maintenance of International Atomic Time (TAI), and the determination of world-wide standard times through the operation of four cesium atomic clocks and the use of GPS satellites. Moreover, we provide a standard time reference service through the internet.

As of February 2023, these responsibilities are carried out at Mizusawa Campus, but they will be moved to Mitaka Campus gradually.

HeadTetsuharu Fuse

Activities Introduction

Maintaining and Disseminating Japan Central Standard Time

We maintain and disseminate Japan Central Standard Time through the operation of four cesium atomic clocks and an NTP sever.

Ishigakijima Astronomical Observatory

Astronomy Outreach Using “the Other Subaru Telescope”

Head: Hidekazu Hanayama

Astronomy Outreach Using “the Other Subaru Telescope”

Ishigakijima Astronomical Observatory is a unique facility in that it is operated by a collaboration of six entities: NAOJ, Ishigaki City, Ishigaki City Education Committee, the Specified Nonprofit Corporation Yaeyamahoshinokai, Okinawa Prefecture Ishigaki Youth Center, and the University of the Ryukyus. This observatory has a 105-cm optical-infrared reflector, the Murikabushi Telescope, the largest of its kind in the Kyushu-Okinawa region, conducting public outreach, education, and research activities in astronomy. The word “Murikabushi” is from the Yaeyama dialect spoken in Ishigaki Island, meaning “the Pleiades,” also known as “Subaru” in Japan. And because of this reason, this telescope is affectionately called NAOJ’s “other Subaru Telescope” after the true Subaru Telescope in Hawaiʻi.

The Yaeyama Islands, including Ishigaki Island, have the starriest skies among the permanently inhabited regions of Japan.

Additionally, the following factors make the place particularly suitable for astronomical observations.

- Low-levels of jet-stream disturbance making stars more visible
- Location that enables us to see the Milky Way with the naked eye

Taking advantage of such a wonderful environment, we provide high-quality images of astronomical objects as well as conduct stargazing parties, public tours, and hands-on observations for high school students. We also collaborate with other research projects both inside and outside of Japan to perform cutting-edge observations of Solar System objects and transient objects.

Head of the Ishigakijima Astronomical Observatory: Hidekazu Hanayama

Our Activities

Providing High-Quality Astronomy Images

We contribute to raising public awareness of astronomy by providing high-quality astronomy images and holding stargazing parties.

Education Through Astronomical Observations

Taking advantage of an ideal environment for astronomical observations, we offer educational programs such as school tours and hands-on observations.

Addressing the Latest Cosmic Mysteries

Collaborating with both domestic and overseas institutions, we perform cutting-edge observations of Solar System objects and transient objects using the Murikabushi Telescope.


Public Relations Center

2-21-1 Osawa, Mitaka, Tokyo 181-8588, JAPAN Google Map

South Building 3F/2F/1F

Contact us