Subaru and Us


the electric-wave telescope
The electric-wave telescope at Nobeyama.

Designing and making Subaru was a very long process. It took over 20 years from the idea stage to completion. Guiding the team through this journey was the enthusiasm of scientists who wanted to see what was in space as far away as 15 billion light years from the earth.

Japanese astronomy has produced many positive results through the electric-wave telescope installed at Nobeyama in Nagano Prefecture and through X-ray satellite observation. Japan's biggest optical telescope used to be the reflective telescope at Okayama Astrophysical Observatory, which was completed in 1960 and has an aperture of 1.88 meters (6.2 feet).

The Okayama telescope was the fifth largest in the world when it was built, but many countries around the world have since built bigger telescopes. Some astronomers had the idea of building a new, bigger telescope and set off to study various places where a new observatory could be built in Japan and other countries.

After deciding where to build the telescope, the plan began with a request for money from the government in 1991. During the planning the team asked the public to suggest names for the telescope. About 3,500 ideas came from all over Japan, and Subaru was chosen as the best.

the Pleiades
The Pleiades, known as the Subaru in Japan.

Subaru is the name of a star cluster in the Taurus constellation, known as the Pleiades in the West. The six or seven bright stars in the cluster have long been loved by people looking at the night sky. They are even mentioned in The Pillow Book, a famous essay collection from the Heian Period (794-1192). Subaru actually comprises over 100 stars, including those that are not so bright. It formed about 50 million years ago, which is quite young for a star cluster.

However, just as the telescope's name was decided and the plan began to take shape, the mood in Japan changed. Economic problems caused people to question big scientific projects that were unlikely to bring immediate profits. "What use is a big telescope?" they asked. Keiichi Ohira, who was the director of the National Astronomical Observatory of Japan at the time, traveled backwards and forwards between Hawaii and Japan many times in order to promote the Subaru project. He was determined that Subaru should contribute to the future development of astronomy.

The overall cost of building Subaru was 40 billion yen. This is no small amount, but results of observations are helping to unravel some of the mysteries of the vast space surrounding the earth, including what happened at the beginning of space and the existence of other planets like the earth. The facility is used not only by Japanese researchers but also by many groups from outside Japan. Subaru is a treasure for all of humankind that is taking us on a heart-stopping adventure to discover space.

Photos: National Astronomical Observatory of Japan


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