CHARAC TERISTICS OF THE BEL GRADE CATALOGUE OF DOUBLE STARS

摘要

The comparison of the Belgrade Catalogue of Double Stars(BCDS)with the Pre-liminary General Catalogue of Double Stars(PGCDS)was analysed in right ascen-sion,declination,magnitude and spectral type.Existence of Δα and Δδ systematicerrors for all spectral types is indicated.The effect can probably be explained by thedifference in the atmospheric refraction for different spectral types.This depends onthe quality of the determined right ascensions and declinations derived from observa-tions of stars at some observatories.