Apparent solar time

Apparent Solar Time
Related Category: Astronomy: General
see solar time.
More on Apparent Solar Time
Solar Time - time defined by the position of the sun.

Apparent solar time is based on the apparent solar day, which is the interval between two successive returns of the Sun to the local meridian. Solar time can be measured by a sundial.

Apparent Solar Time - Time kept according to the actual position of the Sun in the sky. Apparent solar noon occurs when the Sun crosses an observer's meridian ...

Apparent Solar Time
The measure of time based on the diurnal motion of the true Sun. The rate of diurnal motion undergoes seasonal variation because of the obliquity of the ecliptic and because of the eccentricity of the Earth's orbit.

The apparent solar time (based on the actual sun) and the mean solar time (based on the mean sun) can differ by as much as 15 minutes at certain seasons. The difference between the two is called the equation of time.

apparent solar time (NASA SP-7, 1965) See solar time. apparent stresses (NASA SP-7, 1965) = Reynolds stresses. apparent sun (NASA SP-7, 1965) The actual sun as it appears in the sky. Also called true sun .

mean solar time = apparent solar time + EoT
but this sign convention is by no means universal and the opposite sign is used in modern almanacs.

For mission operations purposes, they defined a time scale that would match the clock used for the mission to the apparent solar time about halfway through the nominal 90-sol prime mission.

A Dictionary of Astronomy entry for apparent solar time
The Columbia Encyclopedia, Sixth Edition entry for mean solar time
The Columbia Encyclopedia, Sixth Edition entry for local solar time ...

Interval between two successive culminations of the Sun - i.e., the period from apparent noon to apparent noon. The apparent Solar day is longest in late December. [H76]
Apparent Solar Time ...

See also: Time, Apparent, Solar, Solar time, Sun