SIMBAD references

During four years, systematic observations have been conducted in drift scan mode with the Bordeaux automated meridian circle in the declination band +11°≤δ≤+18°. The resulting astrometric catalog includes about 2.3x10⁶ stars down to the magnitude limit V_M=16.3. Nearly all stars (96%) have been observed at least 6 times, the catalog being complete down to V_M=15.4. The median internal standard error in position is ∼ 35 mas in the magnitude range 11<V_M<15, which degrades to ∼50mas when the faintest stars are considered. M2000 also provides one band photometry with a median internal standard error of ∼0.04mag. Comparisons with the Hipparcos and bright part of Tycho-2 catalogs have enabled us to estimate external errors in position to be lower than 40mas. In this zone and at epoch 1998, the faint part of Tycho-2 is found to have an accuracy of 116mas in α instead of 82mas deduced from the model-based standard errors given in the catalog.