apparent solar time

Mars Pathfinder used the local apparent solar time at its location of landing.

Apparent solar time is the calculation of time based in the relative position of the sun.

This dial shows the difference in minutes between the apparent solar time and the mean solar time.

It corrects apparent solar time to mean solar time or another standard time.

Apparent solar time or true solar time is based on the apparent motion of the actual Sun.

Mean solar time was originally apparent solar time corrected by the equation of time.

Times in the Almanac were in apparent solar time, because time aboard ship was most often determined by observing the Sun.

Positive values indicate that the apparent solar time is ahead (fast) of the mean solar time, with maxima around November 3 and May 15.

In the unusual case that the mean solar time of an observation was needed, one would apply the equation of time to apparent solar time.

Astrarium Solar Tempometer: Apparent solar time in a digital display.

The start of each year was determined according to which day the autumnal equinox occurred, in relation to true or apparent solar time at the Paris Observatory.

Note that the solar day starts at noon, so apparent solar time 00:00 means noon and 12:00 means midnight.

Negative values indicate that the apparent solar time is behind (slow) of the mean solar time, with a maximum lag around February 12 and July 27.

An analemma may be added to many types of sundials to correct apparent solar time to mean solar time or another standard time.

Two types of solar time are apparent solar time (sundial time) and mean solar time (clock time).

Mean solar time has days of equal length, but the difference between mean and apparent solar time, called the equation of time, averages to zero over a year.

In the late 17th and 18th Centuries, equation clocks were made, which allowed the user to see or calculate apparent solar time, as would be shown by a sundial.

The apparent solar time is a measure of the Earth's rotation and the difference between it and the mean solar time is known as the equation of time.

As the variation accumulates over a few weeks, there are differences as large as 16 minutes between apparent solar time and mean solar time (see Equation of time).

Decimal time would also have been reckoned according to apparent solar time, depending on the location it was observed, as was already the practice generally for the setting of clocks.

Mean solar time, for the same place, would be the time indicated by a steady clock set so that over the year its differences from apparent solar time average to zero.

From 1767 to 1833, the British Nautical Almanac and Astronomical Ephemeris tabulated the equation of time in the sense 'mean minus apparent solar time'.

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.

When one says that a sun-synchronous orbit goes over a spot on the earth at the same local time each time, this refers to mean solar time, not to apparent solar time.

These are apparent solar time, which directly tracks the motion of the sun, and mean solar time, which tracks a fictitious "mean" sun with noons 24 hours apart.