Some Effects of Different Sources of Variation of Latitude Data on Meridian Circle Catalogues

Abstract

Fundamental meridian circle observations require the variation of latitude to be applied before the observations are combined to form a catalogue. In the past 80 years, different observatories have used various determinations of polar motion to reduce their observations. This study shows that the use of different determinations of the latitude variation significantly affects the individual observations and can introduce large zonal errors of the level of 0.05 seconds of arc into the catalogue's declination system.