The Annual Fluctuation in the Rate of Rotation of the Earth

Abstract

The amplitude of the apparent annual fluctuation in the rate of rotation of the Earth decreased in 1950 and has since remained at the lower value. Furthermore the fluctuation observed at stations in the northern hemisphere is due in part to systematic errors in the FK3 star places. The extreme range in the length of the day is now estimated as ± 0.5 millisecond. Comparable results are deduced from time observations made in America and Australia.