Secrets of the
Subaru Telescope

How much do you know about the Subaru Telescope?

Japan’s telescope in Hawai‘i

The Subaru Telescope is a world-class telescope near the top of a mountain called Maunakea on the Big Island of Hawai‘i , U.S.A. National Astronomical Observatory of Japan constructed the telescope on the mountain, because Maunakea is one of the best places on the planet for astronomical observations. Over 20 years have passed since the start of its operation, but we are grateful that our telescope is still at the forefront of astronomical research.

1,000 times shaper vision than human eye

As the excellent conditions on Maunakea enable the extraordinary capability to view objects in great detail, the Subaru Telescope can distinguish a coin 100 kilometers away from it.

Maunakea stands at 4,205 meters above sea level. Because of this altitude, it is occasionally covered with snow in winter.

Maunakea is an important place for people in Hawai'i. We deeply respect their values, and ensure minimum impact of the telescope operation on the mountain.

Two more sections to learn!

Giant mirror allows astronomers to see farther into Universe

The Subaru Telescope has a primary mirror with a large aperture of 8.2 meters in diameter. This large mirror can gather lots of light, enabling astronomers to view very faint and distant objects. The telescope’s extraordinary light-gathering capability has transformed the history of astronomy many times.

The primary mirror has an aperture of 8.2 meters, making this single-piece mirror one of the largest in the world. Crafted over a period of 7 years, the mirror was transported to its final destination with the utmost care.

Although 8.2 meters in diameter, the primary mirror is just 20 centimeters thick. 261 finger-like robots called actuators support the enormous, thin mirror from warping when the telescope moves.

The mirror gets dirty or fogs up as it is used. We regularly clean it, and conduct re-coating of the surface.

One more section to learn!

World-class technology and instruments

Both the telescope manufactured by Japan’s advanced technology, and a diverse range of science instruments, which are exchangeable, are combined to enable the Subaru Telescope’s world-leading observations. Observational data which unveils hidden features of the Universe is available not just for Japanese researchers but researchers worldwide. It leads to many astronomical discoveries.

The dome that protects the main body of the Subaru Telescope.

The enclosure protects the telescope from wind, rain and snow. The cylindrical shape is optimal for smooth airflow, minimizing air turbulence inside the enclosure.
Click here to see how the enclosure shutter opens and closes.

The telescope rotates in horizontal and vertical directions to point the mirror system in the direction of a target astronomical object, enabling astronomers to track the motion precisely.

Subaru Telescope with a camera at prime focus.

Astronomers use various science instruments to study the Universe. As of 2022, 6 instruments are in use at the Subaru Telescope. The Subaru Telescope is unique among 8-10m class telescopes by having a camera at the prime focus.

Wow, you’ve learned a lot about theSubaru Telescope!