Introduction

.... many methods - especially in astronomical clocks - need the main two components of the Equation of be added together. This shows the common means to do so.

Cams and Profiles in Sundials

.... cams are the commonest way to convert the Equation of time to linear motion.

Equation Clocks : Background

.... in the 17th - 19th C, many clocks were provided with Equation of Time mechanisms of ever greater sophistication. Initially this allowed the clocks to be set to read solar time and later to use a sundial to set the clock to local mean time..

Equation Clocks 1 : Forerunners

.... in the late 17th/early 18th C clocks were at last accurate for people to distinguish between solar and mean time. This page charts the first steps in the generation of Equation Clocks.

Equation Clocks 2 : Cams

.... from early 18th C, clocks were provided with an Equation of Time "Kidney" cam to allow reading of both solar and mean time.

Equation Clocks 3 : Gears

.... with the invention of the differential gear adder, output from a kidney cam could be added to mean time to give a clock dial directly reading both mean and solar time.

Equation Watches

.... this page for the very rich!

Astronomical Modelling

.... the Lusby Taylor method to generate the Equation of Time.