The Bordeaux and Valinhos CCD meridian circles

A first CCD 512 x 512 camera working in scan mode (declination field 14') w as mounted in 1994 on the Bordeaux CCD meridian circle, After a testing per iod, this camera was installed on the Valinhos CCD meridian circle (near Sa o Paulo, Brazil), as part of a collaboration between Bordeaux Observatory a nd the Institute Astronomico e Geofisico of Sao Paulo. A second improved CC D 1024 x 1024 camera, with a declination field of 28', was installed on the Bordeaux instrument in June 1996. The mean internal precision of a single observation is about 0.04 " in both coordinates for 9 less than or equal to V less than or equal to 14. In the same magnitude range, magnitudes can al so be obtained with an internal precision of about 0.05 mag. Both instrumen ts can participate efficiently in extending the Hipparcos-Tycho frame, duri ng the next decade. Among other duties, the Bordeaux CCD meridian circle is being used since January 1997 for completing the Meridien 2000 project. Th e characteristics of both instruments and some results obtained with them a re presented in this paper.