Reference stars compiled catalogue around extragalactic radio sources. Reduction techniques and the first results

Abstract

Some differential reference stars catalogues around extragalactic radio sources obtained from photographic and CCD-observations at different observatories are considered. Compiled catalogue of star positions in fields of 30 ×30 is intended for reduction of ERS optical observations using the telescopes equipped with CCD-cameras. Photographic observations of the fields around 74 ERS were made at the Pulkovo Observatory, around 115 ERS – at the AO KNU, around 188 ERS – at the AIRA in Bucharest. The 208 fields around ERS at NAO using the telescope equipped with a CCD-camera were obtained. The first results of the creation of uniform compiled catalogue are given. Astrometric positions for stars brighter than 16 magnitude in more than 20 fields around ERS are presented. A comparison of our results with those of other authors is made.