SUGITANI Koji Nagoya City Univ, Institute of Natural Sciences, Assoc. Professor, 自然科学研究教育センター, 助教授 (80192615)
HIRAO Takanori Nagoya Univ, Department of Physics, Research Associate, 大学院・理学研究科, 助手 (00293689)
NAGATA Tetsuya Nagoya Univ, Department of Physics, Assoc. Professor, 大学院・理学研究科, 助教授 (80208016)
TANABE Toshihiko Univ of Tokyo, Inst of Astronomy, Research Associate, 大学院・理学系研究科, 助手 (90179812)
TANAKA Masuo Univ of Tokyo, Inst of Astronomy, Assoc. Professor, 大学院・理学系研究科, 助教授 (70188340)
We have developed a 1.4-m telescope, and put it at South African National Astronomical Observatory (SAAO), Sutherland, South Africa.
In 1999, we made an alt-azimuth mounting, and visited SAAO to discuss the specification of the telescope dome, which SAAO were making. The alt-azimuth mount has advantages of compactness and gravitational symmetry compared with the equatorial mount. However, we have to have an instrument rotator, and have to move the altitude, azimuth, and rotator axes at various speed. We have selected precision encoders and control these axes with well-tuned feedback loops.
In 2000, we completed the control system, and took the whole telescope to SAAO.We made telescope nalysis using an optical CCD.With the resultant telescope parameters, the pointing accuracy of the telescope is 3 arcsec, which is among the best values of this class telescopes.
In November 2000, the near-infrared three-band camera SIRIUS was attached to the telescope. We started test observations. We confirmed that the telescope fulfills the tracking and optical specifications. We have found the necessity of controlling the mirror temperature to have good mirror seeing. We have also improved the robustness of the telescope against wind.