Observations of radio stars at the Valinhos CCD Meridian Circle ^*

¹ Observatório Nacional/CNPq, Brasil
² Pulkovo Observatory, Russia
³ Instituto Astronômico e Geofísico/USP, Brasil
⁴ Observatório do Valongo/UFRJ, Brasil
⁵ Observatoire de Bordeaux, France

Send offprint request to: P.A.A. Lopes, Observatório Nacional/CNPq, R. Gal. José Cristino 77, CEP20921-400, Rio de Janeiro, Brasil. e-mail: afranio@on.br

Received: 27 October 1998
Accepted: 18 February 1999

Abstract

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.