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Old November 21st 17, 09:11 PM posted to sci.astro.amateur
Gerald Kelleher
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Default The Equation of Time(keeping)

On Tuesday, November 21, 2017 at 9:05:46 AM UTC, Martin Brown wrote:
On 19/11/2017 10:34, Mikko wrote:
In article ,
Gerald Kelleher wrote:

The basic experiment involves either a sand or water clock. The period of one
noon to the next full cycle would generate different volumes of water and
sand reflecting the variation in the total length of each individual cycle .

Sand and water clocks are too inaccurate to detect the variation in
duration from one noon to the next.

Actually they were just about good enough to do it a long time ago.

Martin Brown

The Equation of time is a global observation hence there is no declination component or 'tilt' involved. An observation of noon along the entire length of any given longitude meridian where the Sun becomes visible each cycle (sunrise/sunset) will generate the same Equation of Time correction.

Many of these websites mix up the variable annual motion of the Sun in declination with the variable total length of the natural noon cycle and therefore will never come to the right conclusion. The greatest change in declination is centered around the Equinoxes but this slows until it stops entirely at the Solstices. This variation in declination feature has nothing whatsoever to do with the Equation of Time or any hemispherical arc of the Sun.

The Equation of Time, before any other perspective is applied, isolates daily rotation as a constant by assumption but not by direct observation. It is unlikely that many could grasp the importance of this fact but it is the key to understanding everything else including why the clockwork solar system is a chain on astronomy and not a treasure.