![]() After detailed measurements at various observatories around the world, the discrepancy was corrected by the introduction of a new time designation called UT1. This was later found to be caused by a wobble in the axis of the Earth. At each Bloomberg data center, there are multiple GPS time receivers with. Early atomic time scales consisted of quartz clocks with frequencies calibrated by a single atomic clock the atomic clocks were not operated continuously. One second of TAI time is a constant duration defined by cesium. With emergence of better clocks, astronomers began to notice a discrepancy in UT0 measured at different locations. Global positioning satellites each have multiple atomic clocks that are coordinated to send transmit the official time. Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. TAI, Temps Atomique International (French for International Atomic Time), measures real time. "Universal Time" (UT0) is the "Mean Solar Time" at the Greenwich meridian (longitude 0 degree), also known as "Greenwich Mean Time" (GMT). ![]() Starting in 1956, WWV broadcast an atomic clock signal stepped by 20 ms increments to bring it into agreement with UT1. ![]() A more uniform time standard called "Mean Solar Time" is defined by the uniform motion of a fictitious Sun on the celestial sphere that agrees with the averaged "Apparent Solar Time". UT0 and UT2 soon became irrelevant due to the introduction of Coordinated Universal Time (UTC). However, as the Earth revolves around the Sun in an elliptical orbit, and due to the inclination of the Earths rotation axis to the orbital plane, the speed of the apparent motion of the Sun varies through the year and "Apparent Solar Time" is as such non-uniform. Mounted in a handsome black, hard plastic frame, the MFJ-121B features HUGE, easy-to-see 2 tall by 1½ wide LCD numerals and also has running seconds display. In the past, people used sundial to indicate the time derived from the sun's apparent position, and was referred to as "Apparent Solar Time". Read both UTC and local time at-a-single-glance with this MFJ-121B dual atomic clock. For example, the occurrence of day and night is caused by the rotation of the Earth, and seasons by the Earth revolving around the Sun. Astronomical Time is based on the repetition of astronomical events for setting frequency standards.
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