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EquationOfTtme |
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Calculates the equation of time in seconds at the given date
function EquationOfTime(date: TDateTime): extended;
Description Calculates the difference between the mean solar noon and the apparent solar noon for the given date. Mainly due to the eccentricity of the earth's orbit around the sun the time between two real noons is not constant, but changes with the date - the extreme values are up to 16 minutes difference between the mean and the apparent value. This function returns the value in seconds, and can have both positive and negative sign. A negative sign means that real noon is before 12 o'clock, positive sign it's after 12 o'clock.
Reference This function is based upon chapter 28 (27) of "Astronomical Algorithms". |