EDP Sciences
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Volume 393, Number 1, October I 2002
Page(s) 331 - 337
Section Celestial mechanics and astrometry
DOI http://dx.doi.org/10.1051/0004-6361:20020989

A&A 393, 331-337 (2002)
DOI: 10.1051/0004-6361:20020989

Estimation of zonal errors in star catalogs using CCD observations of ICRF sources

A. Fienga1 and A. H. Andrei2

1  Institut de mécanique céleste et de calcul des éphémérides - Observatoire de Paris, EP 1825 CNRS, 77 avenue Denfert-Rochereau, 75014 Paris, France
2  Grupo de Estudos em Astronomia-OV/UFRJ and Observatório Nacional/MCT, R. Gal. José Cristino 77, S. Cristovão, R. Janeiro, Brasil

(Received 10 April 2002 / Accepted 2 July 2002)

38 optical counterparts of ICRF sources were observed and positions were deduced using USNO A2.0 stars and stars extracted from the preliminary version of the GSC II catalog, named GSC2.2. These positions were compared to the ICRF positions, and to other published positions of the same optical counterparts. A significant distortion of the USNO A2.0 catalog is revealed for stars fainter than the 11th magnitude and with declinations from 0 to 20 deg. On the other hand, the preliminary version of the GSC II catalog shows a very good external accuracy and a good homogeneity in right ascension and declination for the observed zones.

Key words: astrometry -- catalogs

Offprint request: A. Fienga, fienga@bdl.fr

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© ESO 2002