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  2. Atomic Clock Ensemble in Space - Wikipedia

    en.wikipedia.org/wiki/Atomic_Clock_Ensemble_in_Space

    After earlier plans for launch readiness in 2012, [5] the clock ensemble was expected to travel to the space station aboard a SpaceX Falcon 9 in 2021. [6] Major delays due to difficulties in the development and test of the active hydrogen maser and the time transfer microwave system have extended the launch to 2025. [ 7 ]

  3. Atomic clock - Wikipedia

    en.wikipedia.org/wiki/Atomic_clock

    In 1968, the SI defined the duration of the second to be 9 192 631 770 vibrations of the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom. Prior to that it was defined by there being 31 556 925.9747 seconds in the tropical year 1900. [20]

  4. United States Naval Observatory - Wikipedia

    en.wikipedia.org/wiki/United_States_Naval...

    Atomic clock ensemble at the U.S. Naval Observatory. The U.S. Naval Observatory operates two “Master Clock” facilities, one in Washington, DC, and the other at Schriever SFB near Colorado Springs, CO. The primary facility, in Washington, D.C. maintains 57 HP/Agilent/Symmetricom 5071A-001 high performance cesium atomic clocks and 24 hydrogen ...

  5. History of timekeeping devices - Wikipedia

    en.wikipedia.org/wiki/History_of_timekeeping_devices

    The caesium atomic clock maintained by NIST is accurate to 30 billionths of a second per year. [206] Atomic clocks have employed other elements, such as hydrogen and rubidium vapor, offering greater stability (in the case of hydrogen clocks) and smaller size, lower power consumption, and thus lower cost (in the case of rubidium clocks). [206]

  6. List of atomic clocks - Wikipedia

    en.wikipedia.org/wiki/List_of_atomic_clocks

    This page was last edited on 6 December 2024, at 01:21 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply.

  7. International Atomic Time - Wikipedia

    en.wikipedia.org/wiki/International_Atomic_Time

    It was used as a basis for calibrating the quartz clocks at the Royal Greenwich Observatory and to establish a time scale, called Greenwich Atomic (GA). The United States Naval Observatory began the A.1 scale on 13 September 1956, using an Atomichron commercial atomic clock, followed by the NBS-A scale at the National Bureau of Standards ...

  8. Department of Defense master clock - Wikipedia

    en.wikipedia.org/wiki/Department_of_Defense...

    The master atomic clock ensemble at the U.S. Naval Observatory in Washington D.C., which provides the time standard for the U.S. Department of Defense. [1] The rack mounted units in the background are caesium beam clocks. The black units in the foreground are hydrogen maser standards.

  9. Atomic Clock (disambiguation) - Wikipedia

    en.wikipedia.org/wiki/Atomic_Clock_(disambiguation)

    An atomic clock is a time keeping device. Atomic Clock Ensemble in Space science project; a clock updated by radio signals which is sometimes called an "atomic clock" Radio clock; the clock as a measure for risk of catastrophic destruction Doomsday Clock