Its position and apparent movement around the sky.
"Apparent solar time" is based on the "apparent solar day", reckoned by defining as 'solar noon' the moment of the Sun's highest altitude above the horizon on any given day. (That's when the Sun crosses the observer's meridian.)
Apparent solar days do not have the exact same length (from one solar noon to the next) throughout the year, which is surprising to some at first.
This is why the first approaches to creating a solid "standard time" involved determining the length of the 'mean solar day' (average solar day).
The position of the sun in the sky,
best done with a sundial.
Apparent solar time is ahead of the clock in Spring and Fall. Apparent solar time is seen while using a sundial.
Standard solar time
apparent solar time
the amount of time the sun takes to cross the meridian twice
The retina
Apparent solar time is ahead of the clock in Spring and Fall. Apparent solar time is seen while using a sundial.
Apparent Solar time..
Standard solar time
Because, when using "apparent solar time", the length of a "solar day" varies slightly during the year. (This is because the Earth's orbit isn't exactly circular and the Earth's axis is tilted.) "Clock time" is based on an average (or "mean") of these day lengths, called the "mean solar day". So clocks use "mean solar time". (By coincidence, on the date the question was answered (14th April) "apparent solar time" and 'clock' time are synchronised.) There's another reason for apparent solar time being different from clock time. "Clock time" uses time zones. So, over a wide area, the time on a clock equals the "mean solar time" at a particular, defining, longitude.
It very much depends on what is meant by solar time. Not really, it's fairly clear. There are 2 types of solar time: 1) "Apparent solar time". At any particular place this is called the "local apparent solar time", because it depends on longitude. 2) "Mean solar time". This averages out the natural variations of "apparent solar time". (The word "mean" is just a way of saying "average".) This too is depends on longitude of course, but time zones are used to cover a wide area, for convenience.
Because, when using "apparent solar time", the length of a "solar day" varies slightly during the year. (This is because the Earth's orbit isn't exactly circular and the Earth's axis is tilted.) "Clock time" is based on an average (or "mean") of these day lengths, called the "mean solar day". So clocks use "mean solar time". (By coincidence, on the date the question was answered (14th April) "apparent solar time" and 'clock' time are synchronised.) There's another reason for apparent solar time being different from clock time. "Clock time" uses time zones. So, over a wide area, the time on a clock equals the "mean solar time" at a particular, defining, longitude.
the distance between the solar time i.e Mean time apparent solar time is stated as equation of time. M.t-A.t=equation of time
The Sun
apparent solar time
the amount of time the sun takes to cross the meridian twice
Apparent solar time
The Earth "day" of exactly 24 hours is the "mean solar day""Mean" is basically a scientific way of saying "average". It's called a "solar day " because it's based on the position of the Sun in the sky.There are natural variations in the length of the solar day because of the Earth's elliptical orbit and axial tilt.The "mean solar day" averages out the variations that happen during the year.This makes things much more convenient for everyday life."Mean solar time" is based on the "mean solar day".The "apparent solar day" is the what we actually observe, and its length varies from day to day.A sundial measures "apparent solar time". We can convert this time to mean solar time by using something called "the equation of time".Actually, the sundial shows "local apparent solar time".That's because the time shown by a sundial depends on its exact longitude.For convenience, mean solar time has time zones (based on longitude).So, longitude also affects the relationship between these twomeasures of time.