Calculation of elapsed time by the apparent position of the sun
On a prograde planet like the Earth, the sidereal day is shorter than the solar day. At time 1, the Sun and a certain distant star are both overhead. At time 2, the planet has rotated 360° and the distant star is overhead again (1→2 = one sidereal day). But it is not until a little later, at time 3, that the Sun is overhead again (1→3 = one solar day). More simply, 1→2 is a complete rotation of the Earth, but because the revolution around the Sun affects the angle at which the Sun is seen from the Earth, 1→3 is how long it takes noon to return. [Note that in this diagram, the relative motion, and corresponding angles, are highly exaggerated for illustrative purposes.]
Solar time is a calculation of the passage of time based on the position of the Sun in the sky. The fundamental unit of solar time is the day, based on the synodic rotation period. Traditionally, there are three types of time reckoning based on astronomical observations: apparent solar time and mean solar time (discussed in this article), and sidereal time, which is based on the apparent motions of stars other than the Sun.[1]
^For the three kinds of time, see (for example) the explanatory section in the almanac Connaissance des Temps for 1902, page 759 Archived August 10, 2011, at the Wayback Machine.
Solartime is a calculation of the passage of time based on the position of the Sun in the sky. The fundamental unit of solartime is the day, based on...
of mean solartime at 0° longitude, the currently used prime meridian, and is not adjusted for daylight saving time. The coordination of time and frequency...
Earth time each day. Wristwatches calibrated in Martian time, rather than Earth time, were used by many of the MER team members. Local solartime has a...
Mean Time (GMT), the mean solartime at that location, as an aid to mariners to determine longitude at sea, providing a standard reference time while...
so do the stars. Both solartime and sidereal time make use of the regularity of Earth's rotation about its polar axis: solartime is reckoned according...
satellite systems, Coordinated Universal Time and mean solartime. In general, the numbers obtained from different time systems differ from one another, but...
12 pm, or 12:00 (using a 24-hour clock) or 1200 (military time). Solar noon is the time when the Sun appears to contact the local celestial meridian...
square metre, J/m2) during that time period. This integrated solar irradiance is called solar irradiation, solar exposure, solar insolation, or insolation....
pre-corrected for the equation of time on the date of observation, to form local mean solartime. Noon occurred at different times but time differences between distant...
Synchronisation of the chronometer on GMT did not affect shipboard time, which was still solartime. But this practice, combined with mariners from other nations...
from the center to about 0.2 of solar radius (139,000 km; 86,000 mi). It is the hottest part of the Sun and of the Solar System. It has a density of 150...
its time offset is eight hours (UTC−08:00). The clock time in this zone is based on mean solartime at the 135th meridian west of the Greenwich Observatory...
respect to its orbit around the Sun. The difference between apparent solartime and mean time was recognized by astronomers since antiquity, but prior to the...
difference in hours and minutes between Coordinated Universal Time (UTC) and local solartime, at a particular place. This difference is expressed with respect...
do not observe summer time. Before 1891, each town and city in Metropolitan France had its own time based on local solartime. In 1891, to avoid complications...
subtracting six hours during daylight saving time (UTC−06:00). The clock time in this zone is based on the mean solartime at the 105th meridian west of the Greenwich...
The equation of time describes the discrepancy between two kinds of solartime. The word equation is used in the medieval sense of "reconciliation of a...
local time and the mean solartime is about two and a half hours during summer time. There have been political pushes to change the official time so that...
Local time is the time observed in a specific locality. There is no canonical definition. Originally it was mean solartime, but since the introduction...
Universal Time (UT or UT1) is a time standard based on Earth's rotation. While originally it was mean solartime at 0° longitude, precise measurements...
country. Instead, sundials were historically used to measure the mean solartime. But they could not function at night or if the sky was cloudy, in which...
Shanghai French Concession started to provide a time announcement service using the Shanghai Mean SolarTime provided by the aforementioned observatory for...
European Time (CET) causes major variations in some areas from solartime. Based on solartime, CET would range from 7.5 to 22.5°E. However, for example Spain...
Local mean time (LMT) is a form of solartime that corrects the variations of local apparent time, forming a uniform time scale at a specific longitude...
includes a mechanism that simulates the equation of time, so that the user can read or calculate solartime, as would be shown by a sundial. The first accurate...
A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited...
provinces use mean solartime. The NRC provides both coordinated universal time and mean solartime in its signals. It makes time servers available for...
550519768e-08 exactly. Apparent solartime or true solartime is based on the solar day, which is the period between one solar noon (passage of the real Sun...
The Solar System is the gravitationally bound system of the Sun and the objects that orbit it. It was formed 4.6 billion years ago when a dense region...
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