John Shepherd wrote: 1. The equation of time gives the difference between the sun time and standard time. Your difference is cumulative or integral of the daily difference. The orbital effect has a maximum difference of about 8 minutes (this does not include the inclination effect). Averaging this approximately sinusoidal variation over 6 months is approximately 7 minutes per day. 7 times 180 days = 21 hours.
Actually this point works the other way around. The difference between the length of any given day and the mean day is only handful of seconds. These snippets must be integrated to arrive at the Equation of Time. Integrating the Equation of Time doesn't produce anything meaningful. Actually, I don't think it is possible to directly deduce anything about the length of the seasons (Willy Leenders' question) from the Equation of Time. The answer to his question depends on the mismatch between the direction of the tilt of the Earth's axis (relative to the plane of the orbit) and the axis of the ellipse of the Earth's orbit. This is, however, related to the relative phase of the annual and semi-annual components of the Equation of Time. --Art Carlson -
