UT1
Units & Measurements abbreviation · Time Zone
| Stands for | Universal Time 1 |
|---|---|
| Categories | Units & Measurements |
UT1 stands for Universal Time 1, a time zone abbreviation.
Astronomical time based on Earth's actual rotation angle, measured by very-long-baseline radio interferometry of distant quasars. It drifts irregularly as Earth's spin varies, and UTC is kept within 0.9 second of it.
Example: Telescope pointing software applies the current UT1 correction published by the IERS.
Usage notes
The International Earth Rotation and Reference Systems Service publishes the difference DUT1 = UT1 − UTC, which some radio time signals also broadcast. UT1 is the modern successor of GMT as a measure of mean solar time. Earth has recently been spinning slightly faster than in past decades, one reason no leap second has been needed since 2016.
Related abbreviations
More time zone abbreviations
- PT – Pacific Time
- SAST – South African Standard Time
- SGT – Singapore Standard Time
- SST – Samoa Standard Time
- TAI – International Atomic Time
- TRT – Turkey Time
- UTC – Coordinated Universal Time
- WAT – West Africa Time
- WEST – Western European Summer Time
- WET – Western European Time
- WIB – Waktu Indonesia Barat (Western Indonesia Time)
- Z – Zulu time (UTC)