M2000 : an astrometric catalog in the Bordeaux Carte du Ciel zone +11 degrees < {delta} < +18 degrees

During four years, systematic observations have been conducted in drift scan mode with the Bordeaux automated meridian circle in the declination band [+11 ; +18]. The resulting astrometric catalog includes about 2 300 000 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 about 35 mas in the V_M magnitude range [11 ; 15], which degrades to about 50 mas when the faintest stars are considered. M2000 provides also one band photometry with a median internal standard error of 0.04 mag. Comparisons with the Hipparcos and bright part of Tycho-2 catalogs have enabled to estimate external errors in position to be lower than 40 mas. In this zone and at epoch 1998, the faint part of Tycho-2 is found to have an accuracy of 116 mas in alpha instead of 82 mas deduced from the model-based standard errors given in the catalog.Comment: The catalogue can be fetched directly from: ftp://cdsarc.u-strasbg.fr/cats/I/272 or queried from: http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/272 More information at : http://www.observ.u-bordeaux.fr/~soubiran/m2000.ht

Observations of radio stars at the Valinhos CCD Meridian Circle

We present the astrometric results from the optical observation of 16 stars from the list of of Wendker (1995), with detected or suspected radio emission. The results are given on the Hipparcos/Tycho reference frame. The stars are evenly distributed in right ascension and the declinations range from -15.6° to +28.6°. This distribution, also allowed to obtain positions relative to the Twin Astrographic Catalogue (TAC 1.0). The observations were carried out with the Valinhos CCD Meridian Circle, in Brazil, operating in drift scanning mode. The average positional precision is at 40 mas and generally below 2 mas/yr for proper motions, obtained with the new reductions of the Astrographic Catalogue - AC2000, as first epoch. In the strips taken from the observation of the 16 radio stars, 573 Tycho stars, 545 ACT stars and 566 TAC stars were found. The analysis of the independent reductions made relatively to those frames and the large number of common stars enables to focus on the equatorial zone, as represented by the three catalogues. As a result, the quality of Valinhos observations with regard to ACT and TAC internal accuracies is verified

The PM2000 Bordeaux proper motion catalogue (+11deg le $ le +18deg)

We present a proper motion catalogue of 2670974 stars, covering the declination zone +11°<=?<=+18°. Proper motions were derived from the comparison of the positional M2000 catalogue (systematic observations of the Bordeaux Carte du Ciel Zone with the meridian circle, completed in 2000) with positions derived from the reduction of 512 Carte du Ciel plates of the Bordeaux zone (scanned at the APM Cambridge), the AC2000.2 catalogue, the USNO-A2.0 catalogue and the unpublished Yellow Sky (YS3) USNO catalogue. The catalogue has a limiting magnitude VM=16.2 (Bordeaux CCD meridian circle magnitude) and is complete down to VM=15.4. Depending on magnitude, the positional precision at mean epoch ranges from 50 to 70mas and the precision of proper motions varies from 1.5mas/yr to 6 mas/yr. Meridian VM magnitudes are provided for all objects together with additional photometry from the 2MASS catalogue when available (99.5% of objects). Positions and proper motions are on the ICRS (International Celestial Reference System). Systematic offsets in 2MASS positions and in UCAC2 proper motions were revealed from comparisons with PM2000

The Bordeaux and Valinhos CCD meridian circles

A first CCD $512\times 512$ camera working in scan mode (declination field $14'$) was mounted in 1994 on the Bordeaux CCD meridian circle. After a testing period, this camera was installed on the Valinhos CCD meridian circle (near São Paulo, Brazil), as part of a collaboration between Bordeaux Observatory and the Instituto Astronomico e Geofisico of São Paulo. A second improved CCD $1024\times 1024$ 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 $9\leq V\leq 14$. In the same magnitude range, magnitudes can also be obtained with an internal precision of about 0.05 mag. Both instruments can participate efficiently in extending the Hipparcos- Tycho frame, during the next decade. Among other duties, the Bordeaux CCD meridian circle is being used since January 1997 for completing the Méridien 2000 project. The characteristics of both instruments and some results obtained with them are presented in this paper

The CdC2000 Bordeaux Carte du Ciel catalogue (+11° &leq; delta &leq; +18°)

Context: .This work is part of a program of proper motion measurements in the Bordeaux Carte du Ciel zone.Aims.We present the CdC2000 catalogue issued from the reduction of the complete Bordeaux Carte du Ciel zone observed at the begining of last century with the Bordeaux astrograph.Methods.Plates have been individually reduced using the TYCHO-2 Catalogue as the astrometric reference. Results.This catalogue is a positional catalogue of 344 781 stars covering the declination zone +11°&leq;delta&leq;+18 °. The average epoch of positions is 1914.7. The data are from the 512 Carte du Ciel plates archived at the Bordeaux Observatory and scanned with the APM Cambridge automatic measuring machine. Astrometric standard errors are about 0.10 arcsec to 0.12 arcsec on positions and 0.6 mag on photographic magnitudes. Conclusions.A detailed study of errors and a comparison of various reduction methods are presented in order to take into account the significant propagated errors from the reference catalogue. The CdC2000 provides positions at the epoch of the plates for 50 682 TYCHO-2 stars. The associated positions are proved to be &surd;{2} more precise than the positions given by the TYCHO-2 catalogue at the epoch of the plates (0.11 arcsec instead of 0.15 arcsec). This work is part of a program of proper motion measurements in the Bordeaux Carte du Ciel zone

Observations des planètes, satellites et astéroïdes avec la lunette méridienne de l'observatoire de Bordeaux

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