The Stacking Method: the Technique to Detect Small Size of GEO Debris

Abstract

We propose a new method that we call “the stacking method” to detect unknown small size of GEO debris. A middle size of telescope and a normal CCD camera are enough to realize a fine result of the method. Many CCD images are used to detect GEO debris. With this method, streaks of stars except debris are disappeared completely and the sky background fluctuation decreases extremely. This means very dark debris, which is not visible on a single image, is detectable. We evaluated this method using actual observation images taken by a 35cm telescope of Mt.Nyukasa Astronomical Observatory and a 2K2K back-illuminated CCD camera. The observation was carried out on 2003 Feb 6th. The total sky coverage of the image area of the CCD camera is about 1.69 square degrees. 150 images with a 10-second exposure time were taken for one geostationary region. Some GEO debris candidates were detected by analyzing the images with the stacking method. Most of the candidates were too dark to be visible on a single CCD image. With this method, by means of observations using a 1m telescope and a back-illuminated CCD camera, we may be expected to detect GEO debris of about 30cm.