ウエスト・バージニア州のパラボラアンテナA visit to the NRAO in Green Bank, WV

I want to describe our visit two days ago to the National Radio Astronomy Osbervatory (NRAO), on December 23. We passed by the observatory on our way to Snowshoe Ski Resort where we have been spending our Christmas holidays.

When I saw the observatory's gigantic telescope from the road, my first throught was that I had to get pictures of it for my profressor, Sharon Traweek, a life-time scholar and expert on the culture of scientific communities, "virtual cities" where inhabitants live and work together conducting research. I also wanted to get lots of information for Professor Keiji Kodaira, the Director of Sokendai, where I am currently based as a visiting researcher in Hayama, Japan. Before he became director of Sokendai, Kodaira-san was a full-time astronomer, and he played a fundamental role in founding the National Astronomical Observatory of Japan (NAOJ), located on Mauna Kea, the tallest volcano in Hawaii. Kodaira-san helped build the world's largest optical telescope, the Subaru. Therefore, I thought he must be interested in this American national observatory with the world's largest radio telescope, the Robert C. Byrd Green Bank Telescope (or the GBT).

Picture of National Astronomy Observatories at Mauna Kea, Hawaii

We took a free tour of the NRAO, where we started at the visitor’s center with a short film and talk given by one of the observatory’s employees. The guide emphasized that the observatory and tour was paid for by the National Science Foundation (NSF), or “your tax dollars.” For that reason, the guide also said that we should feel free to ask whatever questions we wanted.

He said about thirty to forty work there, including technicians, engineers, and astronomers. Some of them live in the residence hall on the campus, but the hall mostly provides accommodations for visiting scientists and teachers. There is an airfield at Green Bank also. When the NRAO was first set up, the guide said, it was hard to get scientists to visit the observatory. The airfield was created so that the NRAO could flly in specialists who didn't want to spend too much time in West Virginia. Now the airfield is no longer used - except in emergencies.

The main reason the airfield isn't used anymore is because the sound of the planes creates interference with the radio waves the telescopes are trying to detect. In fact, Green Bank operates within a "Radio Quiet Zone," protected by the national government. The numerous mountain ridges in West Virginia create a unique setting that blocks the ever-increasing passage of radio interference. In addition to its naturally seclusive environment, the United States National Radio Quiet Zone prohibits all televised and cellular transmissions within its 13,000 sqare miles.

After passing by the residence hall, we saw the Jansky Lab where there are state-of-the-art data collection systems and receivers. Further down the road, we drove by a new Bunk House which can house up to 65 visiting high school and middle school students. Teachers and students can come from anywhere in the United States to conduct their own research projects with one of the site’s telescopes, a 40ft machine built originally in 1962.

In total, there are nine telescopes on the site, including the 40-footer that the observatory sets aside for students. Two of these telescopes are simply replicas or “antiques” commemorating the history of radio astronomy. The Jansky Antenna is a replica of the telescope designed by Karl Jansky in the early 30s for Bell Laboratories. Jansky was given the task of investigation possible sources of static that could interfere with telephone transmissions. Inadvertently, he discovered some static, which he concluded in 1933 was caused by the outside solar system. This accident marked the birth of radio astronomy.

The other “antique” on site is the Reber Telescope built by Grote Reber. The telescope’s 31-foot diameter dish helped Reber to detect several sources of radio waves from space. Based on these detections, he published the first map of the radio sky. Astronomy had been only an optical science until Reber became interested in doing this research that followed up on Jansky’s work.

Like I said, we saw a bunch of telescopes on the tour but the two I remember best are the 140ft Telescope and, of course, the big monster telescope that we saw from the road, the GBT. Completed in 1965, the 140ft Telescope was state-of-the-art in its day. Although it is now somewhat outdated, it is still the largest equatorially mounted telescope in the world. It was retired in 1999, but it served as the site’s primary telescope until then. It is noted for having made the first detection of a “polyatomic molecule in the interstellar medium, and about half of all known molecules today.” According to the guide, the telescope is currently “hibernating” but may be brought back in to service in the future.

The showpiece of the Green Bank Observatory is the GBT, a machine built in 1988. It was built after another, “temporary” 300ft telescope (in service over 20 years) suddenly collapsed in 1988. Apparently this resulted in an emergency appropriation of money from Congress to replace the telescope. We saw the GBT from ten miles away on the road as we were driving, which was pretty exciting. The telescope is the most advanced and largest fully steerable telescope in the world. It was completed in the year 2000. Since then it has detected three new pulsars and, combined with the NRAO telescopes in New Mexico, it has generated a detailed image of the Orion Nebula.