The Bordeaux and Valinhos CCD meridian circles

Abstract

A rst CCD 512 512 camera working in scan mode (declination eld 14 0 ) was mounted in 1994 on the Bordeaux CCD meridian circle. After a test- ing period, this camera was installed on the Valinhos CCD meridian circle (near S~ ao Paulo, Brazil), as part of a collaboration between Bordeaux Observatory and the Instituto Astronomico e Geosico of S~ ao Paulo. A sec- ond improved CCD 1024 1024 camera, with a decli- nation eld of 28 0 , was installed on the Bordeaux in- strument in June 1996. The mean internal precision of a single observation is about 0:04 00 in both coor- dinates for 9 V 14. In the same magnitude range, magnitudes can also be obtained with an in- ternal precision of about 0.05 mag. Both instruments can participate eciently in extending the Hipparcos- Tycho frame, during the next decade. Among other du- ties, the Bordeaux CCD meridian circle is being used since January 1997 for completing the M eridien 2000 project. The characteristics of both instruments and some results obtained with them are presented in this paper.