MONTHLY NEWS
February 1999

Giant New Telescope Is Completed

Since Galileo invented the telescope in the early seventeenth century and impressed the world with eye-opening astronomical discoveries, constant efforts have been made to get clearer, more precise images of the universe.

Subaru, a giant optical-infrared telescope just built by Japan, is among the most advanced in the world. It will give astronomers around the world a close-up view of the sky, including images beyond the visible spectrum (light you can see with the naked eye).

The National Astronomical Observatory spent nearly nine years building it. The observatory that houses the huge telescope is built atop the volcano Mauna Kea on the island of Hawaii, 4,000 meters above sea level. Several observatories owned by such nations as Canada and the United States have been built or are under construction nearby.

In December 1998 Subaru was fitted with a main mirror measuring 20 centimeters thick and 8.3 meters in diameter--the largest of its kind in the world. Japan's largest telescope before Subaru, set up in Okayama Prefecture in 1960, was just 1.9 meters in diameter.

It took almost two years to polish the mirror, the most important part of the telescope. It's made of special glass and was built at a mirror factory in the United States. Because the mirror can warp from its own weight or exposure to heat, it is suspended by 261 arms called actuators.

The observatory, 43 meters high and 40 meters in diameter, is shaped like a cannister to prevent wind from blurring the image captured by the telescope--a problem with many hemispherical-shaped observatories.

On either side of the telescope are black-colored walls 20 meters high and 35 meters across. They'll absorb the heat generated by the telescope and other equipment during observation. The telescope's main mirror will be detached once a year for cleaning.

People expect Subaru to soon become a major center for international astronomy observation. "Operation First Light"--the first experimental astronomical observation--took place at the observatory in January 1999.

Photo: The can-shaped Subaru observatory. (Asahi Shogakusei Shimbun)


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