For interested: https://en.wikipedia.org/wiki/DUT1 https://en.wikipedia.org/wiki/DUT1 > DUT1 = UT1 − UTC > > - Universal Time (UT1), which is defined by

For interested: https://en.wikipedia.org/wiki/DUT1 https://en.wikipedia.org/wiki/DUT1 > DUT1 = UT1 − UTC > > - Universal Time (UT1), which is defined by Earth's rotation > > - Coordinated Universal Time (UTC), which is defined by a network of precision atomic clocks. > > UTC is maintained via leap seconds, such that DUT1 remains within the range −0.9 s < DUT1 < +0.9 s. > > The reason for this correction is partly that the rate of rotation of the Earth is not constant, due to tidal braking and the redistribution of mass within the Earth