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  2. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    Although ERA is intended to replace sidereal time, there is a need to maintain definitions for sidereal time during the transition, and when working with older data and documents. Similarly to mean solar time, every location on Earth has its own local sidereal time (LST), depending on the longitude of the point.

  3. Hour angle - Wikipedia

    en.wikipedia.org/wiki/Hour_angle

    The local hour angle (LHA) of an object in the observer's sky is = or = + where LHA object is the local hour angle of the object, LST is the local sidereal time, is the object's right ascension, GST is Greenwich sidereal time and is the observer's longitude (positive east from the prime meridian). [3]

  4. Time and frequency transfer - Wikipedia

    en.wikipedia.org/wiki/Time_and_frequency_transfer

    In a one-way time transfer system, one end transmits its current time over some communication channel to one or more receivers. [4]: 116 The receivers will, at reception, decode the message, and either just report the time, or adjust a local clock which can provide hold-over time reports in between the reception of messages. The advantage of ...

  5. Greenwich Mean Sidereal Time - Wikipedia

    en.wikipedia.org/?title=Greenwich_Mean_Sidereal...

    Retrieved from "https://en.wikipedia.org/w/index.php?title=Greenwich_Mean_Sidereal_Time&oldid=1163293043"

  6. Earth orientation parameters - Wikipedia

    en.wikipedia.org/wiki/Earth_Orientation_Parameters

    Universal time tracks the Earth's rotation in time, which performs one revolution in about 24 hours. The Earth's rotation is uneven, so UT is not linear with respect to atomic time. It is practically proportional to the sidereal time, which is also a direct measure of Earth rotation. The excess revolution time is called length of day (LOD).

  7. Time standard - Wikipedia

    en.wikipedia.org/wiki/Time_standard

    A sidereal rotation is the time it takes the Earth to make one revolution with rotation to the stars, approximately 23 hours 56 minutes 4 seconds. A mean solar day is about 3 minutes 56 seconds longer than a mean sidereal day, or 1 ⁄ 366 more than a mean sidereal day. In astronomy, sidereal time is used to predict when a star will reach its ...

  8. Terrestrial Time - Wikipedia

    en.wikipedia.org/wiki/Terrestrial_Time

    Terrestrial Time (TT) is a modern astronomical time standard defined by the International Astronomical Union, primarily for time-measurements of astronomical observations made from the surface of Earth. [1] For example, the Astronomical Almanac uses TT for its tables of positions (ephemerides) of the Sun, Moon and planets as seen from Earth.

  9. GMST - Wikipedia

    en.wikipedia.org/wiki/GMST

    Greenwich Mean Sidereal Time, a time scale based on Earth's rate of rotation measured relative to celestial objects Topics referred to by the same term This disambiguation page lists articles associated with the title GMST .