National Astronomical Observatory of Japan

The Subaru Telescope

What is the Subaru Telescope?

The Subaru Telescope is a very large optical infrared telescope installed near the summit of Maunakea, Hawai‘i, USA. Subaru’s primary mirror’s aperture is 8.2 meters, making it one of the largest monolithic mirrors in the world. Its powerful light collecting capability can capture weak light from celestial objects. A major feature of the Subaru Telescope is that its prime focus boasts an overwhelming wide field of view compared to other large telescopes. Various measures have been taken to capture a sharp astronomical image from the collected light, such as a high-performance adaptive optics system. In addition, the high resolution of the Subaru Telescope is highly regarded among the world’s large telescopes. It can be said that this performance was realized by choosing the location carefully and making full use of the latest technology.

The Subaru Telescope


The Subaru Telescope has observed various celestial bodies, from nearby shooting stars to galaxies located 13.1 billion light years away. Observational data taken with the various instruments of the Subaru Telescope such as Suprime-Cam, boasting a wider field of view than other 8-meter telescopes, have been used by researchers not only in Japan, but around the world. These observational data are freely available to the public and are used for various purposes such as high school and university level education.

It has already been nearly 20 years since the Subaru Telescope started its operation, but it is still a telescope that Japan is proud of and it continues to be active on the front lines of astronomy.


LocationSummit of Maunakea on the Island of Hawai‘i, the United States of America (at an altitude of 4139 meters)
Prime manufacturerMitsubishi Electric Corporation
Effective aperture of primary mirror8.2 meters
Main observation instrumentsPrime focus instruments: Hyper Suprime-Cam (HSC)
Nasmyth focus instruments (visible light): High Dispersion Spectrograph (HDS)
Nasmyth focus instruments (Infrared): Infrared Camera and Spectrograph (IRCS) and 188-element Adaptive Optics (AO) System
Cassegrain focus instruments: Multi-Object Infrared Camera and Spectrograph (MOIRCS), Cooled Mid-Infrared Camera and Spectrometer (COMICS), and Faint Object Camera And Spectrograph (FOCAS)
CharacteristicsThe Subaru Telescope has four foci including the prime focus, Cassegrain focus, and two Nasmyth foci. Among the 8-meter class telescopes in the world, only the Subaru Telescope is capable of mounting an instrument at the prime focus.


April 1991The Japan National Large Telescope plan officially started. Construction of the Subaru Telescope started. NAOJ started production of the primary mirror and began overall design. NAOJ asked people from all over Japan to submit names for the telescope.
January 1999The Subaru Telescope started test observation (first light).
December 2000Common use began for the Subaru Telescope.
February 2006Multi-Object InfraRed Camera and Spectrograph (MOIRCS) started operation.
November 2006Laser guide star adaptive optics system started operation (first light).
November 2010Fiber Multi-Object Spectrograph (FMOS) first light.
July 2013Hyper Suprime-Cam (HSC) first light.

Related Project

Subaru Telescope: 20 Years of Observing the Heavens