<gnomoni.ca

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This page shows the Equation of Time rounded to whole minutes: each day's exact value will be within ±1 minute of the value taken from the table.

The value is the adjustment needed to convert from Solar Time to Standard Time (so is the reverse of the IAU convention). You always use the value for the most recent date given, adjusting for Daylight Saving Time when applicable. You are not meant to interpolate inbetween dates; in fact, the table is actually unsuitable for interpolation.

This representation of the Equation of Time has been around for a while and was invented independently several times - by Kevin Karney, Robert Karis, 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 will be valid for many decades to come. At right, there's an example of the output (timezone offset 0) 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.

Dial longitude:
Timezone longitude (of meridian):

Give longitudes as decimal degrees, positive for east of Greenwich, negative west.