United States Naval Observatory

United States Naval Observatory

      in Washington, D.C., an official source, with the U.S. National Institute of Standards and Technology (NIST; formerly the National Bureau of Standards), for standard time in the United States. The positional measurement of celestial objects for purposes of timekeeping and navigation has been the main work of the observatory since its beginning. In 1833 the first small observatory building was constructed near the Capitol. Time signals for the public were first given (1844) by the dropping of a ball from a staff on an observatory building. In 1904 the observatory broadcast the world's first radio time signals.

      The observatory has been enlarged and moved several times. A 102-cm (40-inch) reflecting telescope acquired in 1934 was moved in 1955 to Flagstaff, Ariz., to obtain better atmospheric conditions, and a 155-cm (61-inch) reflector has been in use at Flagstaff since 1964. An optical interferometer of three 50-cm (20-inch) telescopes was built at the Flagstaff station in 1996; three more telescopes were added to the interferometer in 2002. Other stations are maintained in Florida and in Argentina.

      Statutory responsibility for “standard time” (i.e., establishment of time zones in the United States) is currently lodged with the Department of Transportation. The Naval Observatory is specifically responsible for standard time, time interval, and radio-frequency standards for use by the U.S. Department of Defense and its contractors. Both the USNO and the NIST maintain independent time standards, but since October 1968 they have been coordinated to maintain synchronization to approximately one microsecond. USNO broadcasts time and frequency information at intervals (as the NIST does on a 24-hour basis). Both agencies cooperate with the Bureau International de l'Heure in Paris.

* * *


Universalium. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • United States Naval Observatory — USNO redirects here. For other uses, see USNO (disambiguation). The Seal of the USNO with a quote from the Astronomicon, Adde guberandi studium: Pervenit in astra, et pontum caelo conjunxit, Increase the study of navigation: it arrives in the… …   Wikipedia

  • United States Naval Observatory — Observatoire naval des États Unis Vue aérienne de l observatoire naval des États Unis L observatoire naval des États Unis (United States Naval Observatory ou USNO) est une des agences scientifiques les plus anciennes des États Unis. Situé dans… …   Wikipédia en Français

  • United States Naval Observatory — Luftansicht des USNO Das United States Naval Observatory (USNO) ist ein Forschungsinstitut der US Marine. Es befindet sich im nordwestlichen Teil von Washington, D.C.. Inhaltsverzeichnis …   Deutsch Wikipedia

  • United States Naval Observatory Flagstaff Station — Infobox Observatory name = United States Naval Observatory Flagstaff Station caption = organization = United States Naval Observatory location = Flagstaff, Arizona coords = coord|35|11|03|N|111|44|25|W| altitude = 7541 feet (2262 meters) weather …   Wikipedia

  • United States Naval Observatory Flagstaff Station — Luftansicht des USNO Das United States Naval Observatory (USNO) ist ein Forschungsinstitut der US Marine. Es befindet sich im nordwestlichen Teil von Washington D. C.. Inhaltsverzeichnis 1 Geschichte …   Deutsch Wikipedia

  • United States Naval Academy — USNA redirects here. For the fictional nation of the United States of North America, see A Mind Forever Voyaging. United States Naval Academy Motto Ex Scientia Tridens Motto in English …   Wikipedia

  • United States Naval Aviator — Naval Aviator Insignia A United States Naval Aviator is a qualified pilot in the United States Navy, Marine Corps or Coast Guard. Contents 1 Naming …   Wikipedia

  • United States Naval Special Warfare Command — Naval Special Warfare Command Active April 16, 1987 – present …   Wikipedia

  • United States Naval Research Laboratory — Naval Research Laboratory Emblem of the NRL Active 1923 present Country …   Wikipedia

  • United States Naval Forces Europe — emblem United States Naval Forces Europe is the United States Navy component of the United States European Command and provides forces for United States African Command. Commander, U.S. Naval Forces Europe (COMUSNAVEUR) provides overall command,… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”