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UTC

UTC stands for Coordinated Universal Time (or Universal Time Coordinated).
UTC is a successor of and conceptually different from GMT. Nevertheless, UTC is sometimes referred to as GMT.
UTC is independent of time zone values.
Each time zone is expressed as a positibe or negative offset from the UTC.

UT, TT, Delta T

Universal Time (UT) is a time scale based on the Earth's rotation
In contrast, Terrestrial Time (TT) is a (theoretical) uniform time scale.
Delta-T (ΔT) = TT - UT

See also

ISO 8601
VBA: Convert a UTC text to a date
Converting a UTC string to a local time in PowerShell using the .NET class System.DateTime.
Equation of time
International Atomic Time (TAI)

Index

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