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  2. Equation of time - Wikipedia

    en.wikipedia.org/wiki/Equation_of_time

    Here M D is the value of M at the chosen date and time. For the values given here, in radians, M D is that measured for the actual Sun at the epoch, 1 January 2000 at 12 noon UT1, and D is the number of days past that epoch. At periapsis M = 2π, so solving gives D = D p = 2.508 109.

  3. Solar time - Wikipedia

    en.wikipedia.org/wiki/Solar_time

    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 ...

  4. Sunrise equation - Wikipedia

    en.wikipedia.org/wiki/Sunrise_equation

    A plot of hours of daylight as a function of the date for changing latitudes. This plot was created using the simple sunrise equation, approximating the sun as a single point and does not take into account effects caused by the atmosphere or the diameter of the Sun. The sunrise equation or sunset equation can be used to derive the time of ...

  5. Time-to-digital converter - Wikipedia

    en.wikipedia.org/wiki/Time-to-digital_converter

    In electronics time-to-digital converters (TDCs) or time digitizers are devices commonly used to measure a time interval and convert it into digital (binary) output. In some cases [1] interpolating TDCs are also called time counters (TCs). TDCs are used to determine the time interval between two signal pulses (known as start and stop pulse).

  6. Orbital period - Wikipedia

    en.wikipedia.org/wiki/Orbital_period

    The synodic period is the amount of time that it takes for an object to reappear at the same point in relation to two or more other objects. In common usage, these two objects are typically Earth and the Sun. The time between two successive oppositions or two successive conjunctions is also equal to the synodic period. For celestial bodies in ...

  7. Tropical year - Wikipedia

    en.wikipedia.org/wiki/Tropical_year

    The "mean tropical year" is based on the mean sun, and is not exactly equal to any of the times taken to go from an equinox to the next or from a solstice to the next. The following values of time intervals between equinoxes and solstices were provided by Meeus and Savoie for the years 0 and 2000. [11]

  8. Proper time - Wikipedia

    en.wikipedia.org/wiki/Proper_time

    The proper time interval for A between the two events is then = =. So being "at rest" in a special relativity coordinate system means that proper time and coordinate time are the same. Let there now be another observer B who travels in the x direction from (0,0,0,0) for 5 years of A -coordinate time at 0.866 c to (5 years, 4.33 light-years, 0, 0).

  9. Spacetime - Wikipedia

    en.wikipedia.org/wiki/Spacetime

    In physics, spacetime, also called the space-time continuum, is a mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum. Spacetime diagrams are useful in visualizing and understanding relativistic effects, such as how different observers perceive where and when events ...