The precision of time registration with Danjon astrolabe

During 1988 at the Munich, Vienna and Graz stations selected stars were observed for the purpose of determining difference in the longitudes. The measurements were performed with Danjon astrolabe by using the method of equal zenith distances. In the present paper the authors analyze the registration precision of 1604 star transits over a given almucantar. They estimate the variance of registration of star transits over a fictive thread as function of declination and parallactic angle before and after elimination of gross errors.