What is the Radioheliograph?
The Radioheliograph is a radio telescope at NAOJ Nobeyama Campus specialized for observing the Sun. Using 84 antennas, it realizes a resolution equivalent to a radio telescope with a diameter of 500 meters. The time scales of solar surface activity vary from less than 1 second to more than 10 years. The Radioheliograph can take up to 20 images per second, and monitor the solar activity like a video camera. The Institute for Space-Earth Environmental Research, Nagoya University had taken responsibility for its operation since April 2015. The operation was finished on March 31, 2020.
Research
Explosions sometimes occur on the solar surface, producing very high-speed electrons. These electrons twine around the magnetic fields of sunspots and emit strong radio waves. The main purpose of the Radioheliograph observations is to catch these radio waves in order to clarify the origins of the high-speed electrons and the causes of the explosions. We can also observe how plasma flies out of the Sun. This is useful for forecasting the space weather around the Earth.
Specifications
| Location | NAOJ Nobeyama Campus (Nobeyama, Minamimakimura, Minamisaku, Nagano, Japan) |
|---|---|
| Prime manufacturer | NEC Corporation |
| Diameter of antennas | 80 centimeters |
| Number of antennas | 84 antennas. Inverted T shape of 490 meters in the east-west direction and 220 meters in the north-south direction. |
| Observing frequency | 17 GHz and 34 GHz |
| Weight of antennas | About 600 kilograms |
| Spatial resolution | 10 arcsec (17 GHz) and 5 arcsec (34 GHz) |
| Time resolution | 1 second (0.1 sec when an explosion occurs) |
| Observation time | About 8 straight hours per day |
History
| March 1992 | Constructed. Continuous observation started from late June 1992. |
|---|---|
| April 2015 | Following the closure of the Nobeyama Solar Radio Observatory, the operation was transferred to Nagoya University. |
| March 2020 | Operation ended. |
