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Sunlit Design > Gallery > A Dynamic Equation of Time Visualisation


Introduction

A Dynamic Equation of Time Visualisation

This daily changing graphic shows the relationship between true (sun) time and mean (clock) time over the period of a year. Download a SVG viewer from Adobe here.

There is one bar for every 3 days.  The first of each month is marked by a darker bar, with January 1st in red. When the day's bar leans backward then true (sun) time is lagging behind mean (clock) time. This is the case in January and July for example. When the tip of the bar leans forward, true (sun) time is leading mean (clock) time. You can see this in May and particularly in November.

The values for equation of time are shown at low accuracy. They are accurate to plus or minus 30 seconds and are based on solar values that are useful over the next century. See Solar Day of Year Timescale

The graphic was constructed using SVG. See SVG Visualisations for a description of how this was done.