THE U.S. NAVAL OBSERVATORY ATOMIC CLOCK DETERMINATION OF TIME & LOCATION 78394

Made in 1970, this U.S. Navy film presents the mission of the U.S. Naval Observatory in context of the era of space exploration, the creation of the atomic clock, and the need to have very precise measurements of time and space for scientific and defense purposes. The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation and Timing (PNT) for the United States Navy and the United States Department of Defense. Located in Northwest Washington, D.C. at the Northwestern end of Embassy Row, it is one of the pre-1900 astronomical observatories located in an urban area; at the time of its construction, it was far from the light pollution thrown off by the (then-smaller) city center. The USNO operates the "Master Clock", which provides precise time to the GPS satellite constellation run by the United States Air Force. The USNO performs radio VLBI-based positions of quasars with numerous global collaborators, in order to produce Earth Orientation parameters. Aside from its scientific mission, since 1974, the official residence of the Vice President of the United States has been Number One Observatory Circle, a house on the grounds of the Naval Observatory.

At mark 1:08 a simple explanation of Earth positions is defined by longitude for E-W direction and latitude N-S of the equator. At mark 1:33, we have the relating of objects to the sky. We have circumnavigation through celestial object and measuring the angular distance of the celestial body to the horizon and its altitude. Producing, publishing and distributing this Intel is the responsibility of U.S. Naval observatory located in Washington, D.C.

At mark 2:30, the U.S. Naval Observatory buildings are seen. The observatory was established in 1841 to determine precise star positions and time for the purpose of aiding navigation.

At mark 3:20, we have an IBM mainframe computer connected to the linotron, which produces printer copy pages. At mark 3:37, we have the American Emphemeris , a book containing the protective positions, sun moon and the other planets. More than 60,000 copies of other relating books are also published, seen at mark 3:57.

At mark 4:01, we have a special type of telescope called the transit circle. Its name comes from its function. It is constructed to swing from north to south along its meridian. At mark 5:20 we have how the change in day described the position of stars in the sky. At mark 5:55 we see as the observatory uses the transit circle telescope to track down stars as it travels along the meridian. The star position is then read electronically, and stored in the computer for data analysis. Atmospheric conditions are also automatically recorded.

At mark 7:12, we have the Washington observatory building, it’s necessary to keep the observatory instruments from ground level atmospheric disturbances. The environment must be stable against sudden change as we have seen that star positions and determination of time are closely related.

At mark 7:38, we have the master clock room of the time service of the Naval Observatory. They develop three different types of time, using transit telescopes. At mark 8:27, we have how to determine the solar time. At mark 9:10, we have the second type of time which is the emphemeris time, defined by the annual revolution of the earth around the sun and is independent of the earth’s rotation. We use the motion of the moon against the background of the stars to determine emphemeris time. All this depend on careful astrological observation whether continue positions and calibrations. At mark 9:57, we have the reference clock. Atomic time provides the needed independent calibration for standard time and emphemeris time as well as serving the most critical need of science and technology. At mark 10:50, we have a naval observer operating the machines. At mark 11:20, we have the atomic clock being carried to other facilities around the world.

At mark 12:18, we have new studies on the asteroids. At mark 12:42, we have the largest telescope of the observatory in Washington, a 26 inch refractor and is been used for polographic studies of double stars revolving around each other. At mark 13:52, we have in the mountains of northern Arizona another installation of the observatory, this is the Flagstaff station. Here we have the largest of the observatory’s telescope, a 61 inch astrometry reflector. It is used to measured distance of the nearby stars through the motion of the earth around the sun. At 15:00 we have the parallax observations. These observations are made by the 61inch telescope and they are represented in a photograph. These photographs re then measured to determine the parallaxes. Men have looked to the stars and the importance of the US naval observatory is always emphasized.