How is mean solar time defined?

Mean solar time is defined as the average length of the solar day, which is calculated based on an average year of 365.2422 days. This average accounts for the variations in the actual solar time, which can fluctuate due to the elliptical shape of Earth's orbit and its axial tilt. Essentially, mean solar time provides a standardized method of keeping time by averaging the solar day over the course of a year, allowing for more consistent timekeeping that aligns with the natural day-night cycle experienced on Earth.

Understanding mean solar time is crucial for applications in fields such as surveying, where precise measurements of time can influence calculations related to positioning and navigation. This definition reflects a systematic approach to timekeeping, contrasting with other measuring methods that focus on specific celestial events or bodies, such as the moon or stars.