United States Naval Observatory
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Aerial view of USNO. |
The
United States Naval Observatory (
USNO) is one of the oldest
scientific agencies in the
United States. Located in
Northwest Washington, D.C., it is one of the very few
observatories located in an urban area; when it was initially constructed, it was far from the
light pollution generated by the then-smaller city center.
Established in 1830 as the
Depot of Charts and Instruments, it was made into a national observatory in 1842 via a federal law.
James Melville Gilliss was put in charge of the project
The observatory's primary mission was to care for the
United States Navy's
chronometers, charts and other navigational equipment. It
calibrated ships' chronometers by timing the
transit of
stars across the
meridian. Initially located downtown in
Foggy Bottom (near the
Kennedy Center), the observatory moved to its present location in
1893, atop Observatory Hill overlooking
Massachusetts Avenue, amidst perfectly
circular grounds.
The first superintendent was Navy Commander
Matthew Fontaine Maury. Maury had the first
time ball vulcanized, created by
Charles Goodyear, for the United States observatory. It was the first timeball in the United States, and the 12th in the world. Maury kept accurate time by the stars and planets. When the timeball was dropped, a flag was mechanically raised letting all ships and civilians know the exact time. Thus time was kept not only for Washington D.C. but, through the use of the
telegraph, also for every state in the Union. Time was also "sold" to the railroads. Early in the twentieth century, the
Arlington Time Signal broadcast this service to
wireless recivers.
The names National Observatory and Naval Observatory were both used for ten years until a ruling was passed to use only the term Navy Observatory. Former President
John Quincy Adams had intended for it to be called the National Observatory. John Quincy Adams spent many nights at the observatory with Maury watching and charting the stars because it had always been one of Adams' hobbies to study the stars - another reason he passed the bill for the creation of a national observatory just before his leaving presidential office.
Today, as in the past, the modern United States Naval Observatory continues to be a major authority in the areas of time-keeping and celestial observation. In collaboration with the
Rutherford Appleton Laboratory it determines the timing and astronomical data required for accurate
navigation and fundamental
astronomy and distributes this information in the
Astronomical Almanac. Perhaps it is best known to the general public for its highly accurate ensemble of
atomic clocks and its year 2000 Timeball replacement.
Since 1974,
Number One Observatory Circle, a house situated in the grounds of the observatory (formerly the residence of its superintendent), has been the official residence of the
Vice President of the United States.
As of July 2006, the aerial view of the site is
pixelated in
Google Earth and
Google Maps, while aerial views of the rest of Washington can be seen in high resolution.
The US Naval Observatory's time service can be accessed by calling (719) 567-6742 in Colorado Springs, or (202) 762-1401 in Washington, DC.
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United States Naval Observatory Flagstaff Station*
Navy Prototype Optical Interferometer*
List of observatories*
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USNO, "What Time is it?"
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Transcription: Lieut. Matthew Fontaine Maury's 1847 Letter to President John Quincy Adams on the many details of the United States
National (Navy, Naval)Observatory.
