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H. Scholl (OCA), G. Hahn, M. Hoffmann (IPE), A. Maury (OCA), S. Mottola (IPE), ODAS Team
ODAS is an asteroid and comet detection program with special emphasis on NEOs, a joint venture between the Observatoire de la Côte d'Azur (OCA) and the DLR - Institute of Planetary Exploration (IPE), Berlin-Adlershof, Germany. It is operated by the 90cm OCA Schmidt-telescope situated at Calern near Nice. The limiting magnitude is 21m. The current system uses a commonly developed 2Kx2K CCD camera. Observations are mainly carried out in scan mode. Two independent automated asteroid detection software packages are applied. The main difference between the two packages consists in the method to identify an object on a CCD image. The use of automated software requires three observations of the same field per night. Each triplet of scan-images is processed to obtain three catalogs containing positions and magnitudes of identified objects. A comparison of the three catalogs yields a list of alleged moving objects. An interactive blink allows the separation of fake from real moving objects. Astrometric positions are obtained using solely the GSC or the USNO-A catalog. The two software packes yield slightly different sets of detected asteroids. Different asteroids are recognized in particular close to the image borders or in the vicinity of stars or galaxies. Also, the variaiton of the background on an image may be the reason for differing sets. None of the two methods appears superior. Both methods require the choice of certain parameters for the object identification algorithm which determine the ratio between fake and real objects. ODAS began observations in October 1996. Each month, 15 nights of observation time were attributed to the ODAS program. Nearly 6000 objects have been observed. The number of new designations is 1150. Seven Mars-crossing Asteroids and three NEAs have been detected.