"This is a journal covering about 50 years of my interest in the Equation of Time, during which time I have been gathering pictures, charts and ideas on that subject." So starts Kevin Karney's book on the Equation of Time. Kevin was kind to provide his book to both the British Sundial Society and the North American Sundial Society for wider distribution, free of charge. The book was originally published in 2024, exactly at solar noon on the author's 80th Birthday.
The PDF of his book is available for download here:
The Equation of Time - AEquarto Dierum - Kevin Karney.pdf38.31 MB
Kevin has collected several different ways to compute the Equation of Time and they are available here as *.xlsx speardsheets and *.py code:
Excel Spreadsheet for Calculating EoT & Sun Declination.zip509.87 KB
Python Code for Calculating EoT & Sun Declination.zip22.10 KB
Kevin has also collected a number of short videos to demonstrate various ways of calculating and visualizing the Equation of Time. Download the zip file:
EoT Video Animations.zip439.67 MB
Or, view them here:
01-Eccentricity Effect with Exaggerated Eccentricity
02-Eccentricity Effect True Eccentricity
03-Equation of Time (zero eccentricity)
08-EoT from 2xGoodman Tusi and Pulley Adder
09-EoT from 2xNormal Tusi and Pulley Adder
13-Earth EoT and Analemma with Cams
14-Mars EoT and Analemma with Cams
16-Rittenhouse Method Exaggerated
17-Rittenhouse Method with Indicator
18-John Goodman describing his Tusi mechanism
19-Abbey Gardens Sundia l- Bury St Edmunds