An Equation Clock is a highly specialised timepiece that displays both mean solar time (standard clock time) and apparent solar time, accounting for the Earth\'s elliptical orbit and axial tilt. These sophisticated clocks often include an equation of time indication, demonstrating exceptional horological skill and astronomical knowledge. Antique equation clocks are rare and highly collectable among enthusiasts of scientific instruments and fine clockmaking. *Related Terms*\ Astronomical Clock, Clock Movement, Equation of Time, Horology, Precision Clock, Scientific Instruments.