Large Optical Telescope
The large optical telescope, the primary mirror of which has a diameter of 1 meter, permits observation over a wide range of 3 degrees. A cooled charge-coupled device (CCD) camera consisting of 10 highly sensitive CCD elements arranged in a mosaic pattern is installed at the focal point of the telescope. A batch of digital image data acquired by the camera is sent to computers where it is analyzed. The telescope can detect space debris of about 50 cm in diameter near the GEO and GTO, and NEOs of at least 1 km in diameter.

Specification of the 1-m Optical Telescope

Focus mode	Cassegrain-type focusing, F/3
Field of view	3 degrees
Max. tracking speed	More than 5 deg./sec (right ascension/declination)
Structure	Folk-type equatorial
CCD camera	Approx. 160-mm imaging diameter Uses ten of 2,000 x 4,000 pixel CCD cell
CCD temperature	Approx. 173K during observations
1-m Optical Telescope

Small Tracking Telescope
The two small telescope, which have primary mirror of 50 cm and 25 cm co-mounted on 50-cm telescope, are principally used to track and observe space debris travelling at high speed. For this season, each telescope is mounted in a structure designed to enable the telescope tube to be moved at a rate of 5 degrees per second. As with the large telescope, a cooled CCD camera is used to acquire image data which is analyzed by computer in order determine the orbit of the space debris and NEOs.

Specifications of the 50-cm and 25-cm Optical Telescope

	50-cm Optical Telescope	25-cm Optical Telescope
Focus mode	Cassegrain-type focusing, F/2	Baker Richey Chretian-type focusing, F/5
Field of view	2 degrees	5 degrees
Max. tracking speed	More than 5 deg./sec (right ascension/declination)	ditto (Mount on 50-cm Optical Telescope)
Structure	Folk-type equatorial	ditto (Mount on 50-cm Optical Telescope)
CCD camera	Approx. 50-mm imaging diameter Uses two of 2,000 x 4,000 pixel CCD cell	2,000 x 2,000 pixel CCD cell
CCD temperature	Approx. 173K during observations	Approx. 243K during observations
Photo

Observation Dome and Observation Room
The observation dome where the large optical telescope is installed has a diameter of six meters; the distance from the floor to the top of the dome is also about six meters. The large optical telescope installed in this dome is fixed to a pier (column) that extends 15 meters above the ground and is independent of the building structure. This ensures that the telescope is unaffected by vibration of the building itself. The inside of the dome is cooled during the day to reduce the difference in temperature between the inside and outside air during night observations.
The observation room where the small tracking telescope are used has a sliding roof. As with the large observation dome, the pier on which 50-cm telescope is mounted is independent of the building structure, and the observation room is also cooled during the day.

Computer System for Space Debris and NEOs Optical Observation

Computer System and LAN
The proposed computer system and LAN for the Bisei Spaceguard Center are shown at right. The large and small telescopes are operated by computer control. In addition, not only is it possible to transmit observation data from the facility to other stations, the telescopes can also be controlled externally.

Observation Plan
Normal observations will involve searching for known and unknown space debris and, between space debris observations, detecting or searching for NEOs that are either approaching or likely to come toward the Earth.