After the War, in 1947, the decision was made to move to Herstmonceux Castle and 320 adjacent acres (1.3 km²), 70 km south-southeast of Greenwich near Hailsham in East Sussex, due to light pollution in London.
Za časovno usklajenost ur na GMT je leta 1833 kraljevi astronom John Pond v observatorij namestil časovno kroglo.