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The United States Naval Observatory states "the Equation of Time is the difference apparent solar time minus mean solar time", i.e. if the sun is ahead of the clock the sign is positive, and if the clock is ahead of the sun the sign is negative. [6] [7] The equation of time is shown in the upper graph above for a period of slightly more than a ...
C is the Equation of the center value needed to calculate lambda (see next equation). 1.9148 is the coefficient of the Equation of the Center for the planet the observer is on (in this case, Earth) Ecliptic longitude
The lengths of time when the sun is up are longer around the summer solstice and shorter around the winter solstice, except near the equator. When the Sun's path crosses the equator, the length of the nights at latitudes +L° and −L° are of equal length. This is known as an equinox. There are two solstices and two equinoxes in a tropical year.
The winter solstice marks the shortest day and longest night of the year, according to the National Weather Service. This occurs due to the Earth's tilt from the sun.
t is the time between these same two events, but as measured in the stationary reference frame; v is the speed of the moving reference frame relative to the stationary one; c is the speed of light. Moving objects therefore are said to show a slower passage of time. This is known as time dilation.
The solar zenith angle is the zenith angle of the sun, i.e., the angle between the sun’s rays and the vertical direction.It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the sun’s rays and a horizontal plane.
The summer solstice occurs for Earth’s upper half when the Northern Hemisphere is tilted most closely toward the sun. This also marks the longest day and shortest night of the year. Around the same time, the Southern Hemisphere is at its most extreme tilt away from the sun, entering winter solstice and its shortest day of the year.
The solstice usually – but not always – takes place on December 21. The date that the solstice occurs can move forward or back by a day because the solar year (the time it takes for the sun to ...