gnomoni.ca

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This page shows the Equation of Time (EoT) rounded to whole minutes: each day's actual noon value will be within ±1 minute of the value taken from the table. The EoT value shown is the adjustment needed to convert from Solar Time to Mean Time, which is the traditional definition but is opposite to the 'usual' IAU definition. As well, pf the settings given below for longitude and time zone differ, the results will include the additional adjustment needed to convert from Solar Time to Standard Time.

Always use the value for the most recent date given in the table, adjusting for Daylight Saving Time when applicable. You are not meant to interpolate between dates; in fact, the table is actually unsuitable for interpolation.

This representation of EoT has been around for a while and was invented at least twice - by Kevin Karney, me, and perhaps others who I do not know of.

My algorithm uses daily median values for the years 2020 to 2099 so the results should be valid, or very close, for many decades to come. At right, there's an example of the output formatted to be the back of a business card. The number of rows needed depends on your longitude and timezone.

Please note, this page is offered 'as is' for personal interest and informal use; no liability for errors is accepted. It you encounter problems, please contact me using the link on the right of the blue title bar above.