The actual accuracy of latitude observations

Abstract

By analysing the differences between simultaeous latitude measurements by different instruments at one and the same station, we demonstrate that the actual accuracy of latitude observations is much less than the internal accuracy of one instrument and we conclude that the local (non-polar) term is mainly due to various errors such as the irregular refraction in the observing room, and not due to geophysical factors such as tectonic movement and a change of plumb line.