apparent solar time

chronology

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June 18, 2026

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Apparent solar time is a measure of time based on the direct observation of the Sun's position in the sky, typically using a sundial. This differs from mean solar time, which is what most clocks and watches keep. Mean solar time assumes the Sun moves at a constant speed, whereas the actual Sun's apparent speed varies throughout the year due to Earth's elliptical orbit and axial tilt. The difference between these two is called the equation of time and can be up to 16 minutes. Chronology, in general, is any system for ordering events in the sequence they occurred. Modern timekeeping, like Coordinated Universal Time (UTC), combines solar and atomic time.12

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solar time
Apparent solar time is that measured by direct observation of the Sun or by a sundial. Mean solar time, kept by most clocks and watches, is the solar time that would be measured by observation if the Sun traveled at a uniform apparent speed throughout…
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Apparent solar time is that measured by direct observation of the Sun or by a sundial. Mean solar time, kept by most clocks and watches, is the solar time that would be measured by observation if the Sun traveled at a uniform apparent speed throughout…
Read More