Shin-ichiro Okumura

6th Space Debris Workshop (December 17-19, 2014. Chofu Aerospace Center, Japan Aerospace Exploration Agency (JAXA)(CAC)), Chofu, Tokyo, JapanBisei Spaceguard Center was built as a facility for the purpose of the optical observations of space debris and near Earth asteroids. Since 2000, observations have been carried out with three telescopes (1 m, 50 cm and 25 cm). Although main targets are GEO objects, the telescopes have the tracking capability for high-speed moving objects at LEO. The accuracy of the positional measurement is about 0.2-0.3 arcsec, which corresponds to the distance of 40 m at GEO. We are also working on research observations of space debris in recently. For example, the figure shows a short-term light curve of a retired satellite. Two light curves were obtained in 2012 and 2014. It shows that the rotation or tumbling status has varied in these two years.Physical characteristics: Original contains color illustrations

5th Space Debris Workshop (January 22-23, 2013, Chofu Aerospace Center, Japan Aerospace Exploration Agency (JAXA)), Chofu, Tokyo, JapanI present the method and the examples of light-curve observations of space debris, using TDI (Time Delay Integration) technique. TDI mode is a readout technique of shifting the charge on the CCD while the shutter is open. It is usually applied to the moving objects with the expected motion, so that they appear as point sources. I tried to apply the TDI method to non-moving objects to derive their short-period light-curves. The advantage of the method and the result of the test observations will be presented here.Physical characteristics: Original contains color illustrations

4th Space Debris Workshop(December 16-17, 2010, Chofu Aerospace Center, Japan Aerospace Exploration Agency (JAXA))We are attempting the observations of geostationary space debris using TDI mode. In TDI-mode observations, the positions of geostationary space debris are able to be measured even if field stars appear as long horizontal streaks because of a long exposure. To make the best use of TDI mode, the use of the "image for a positional measurement" and the image subtraction method were examined. Detection limit for TDI observation was evaluated, and limiting magnitude is estimated to be 18.7 (60sec exposure, S/N ca. 5).Physical characteristics: Original contains color illustrations