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USNO
United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depot of Charts and Instruments, it is one of the oldest Science, scientific agencies in the United States, and remains the country's leading authority for astronomical and timing data for all purposes. The observatory is located in Northwest, Washington, D.C., Northwest Washington, D.C. at the northwestern end of Embassy Row. It is among the few pre-20th century Observatory, astronomical observatories located in an urban area; initially located in Foggy Bottom near the city's center, it was relocated to its current location in 1893 to escape light pollution. The USNO has conducted significant scientific studies throughout its history, including measuring the speed of light, observing solar eclipses, and discovering the moons of Mars. Its ach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Naval Observatory
United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depot of Charts and Instruments, it is one of the oldest scientific agencies in the United States, and remains the country's leading authority for astronomical and timing data for all purposes. The observatory is located in Northwest Washington, D.C. at the northwestern end of Embassy Row. It is among the few pre-20th century astronomical observatories located in an urban area; initially located in Foggy Bottom near the city's center, it was relocated to its current location in 1893 to escape light pollution. The USNO has conducted significant scientific studies throughout its history, including measuring the speed of light, observing solar eclipses, and discovering the moons of Mars. Its achievements including providing data for the first ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrometry
Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way. History The history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements. This can be dated back to Hipparchus, who around 190 BC used the catalogue of his predecessors Timocharis and Aristillus to discover Earth's precession. In doing so, he also developed the brightness scale still in use today. Hipparchus compiled a catalogue with at least 850 stars and their positions. Hipparchus's successor, Ptolemy, included a catalogue of 1,022 stars in his work the '' Almagest'', giving their location, coordinates, and brightness. In the 10th century, Abd al-Rahman al-Sufi carried out observations on the stars and described their positions, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Celestial Reference Frame
The International Celestial Reference System (ICRS) is the current standard celestial reference system adopted by the International Astronomical Union (IAU). Its origin is at the barycenter of the Solar System, with axes that are intended to "show no global rotation with respect to a set of distant extragalactic objects". This fixed reference system differs from previous reference systems, which had been based on Catalogues of Fundamental Stars that had published the positions of stars based on direct "observations of heir equatorial coordinates, right ascension and declination" and had adopted as "privileged axes ... the mean equator and the dynamical equinox" at a particular date and time. The International Celestial Reference Frame (ICRF) is a realization of the International Celestial Reference System using reference celestial sources observed at radio wavelengths. In the context of the ICRS, a reference ''frame'' (RF) is the physical realization of a reference ''system,' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Defense
The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national security and the United States Armed Forces. The DoD is the largest employer in the world, with over 1.34 million active-duty service members (soldiers, marines, sailors, airmen, and guardians) as of June 2022. The DoD also maintains over 778,000 National Guard and reservists, and over 747,000 civilians bringing the total to over 2.87 million employees. Headquartered at the Pentagon in Arlington, Virginia, just outside Washington, D.C., the DoD's stated mission is to provide "the military forces needed to deter war and ensure our nation's security". The Department of Defense is headed by the secretary of defense, a cabinet-level head who reports directly to the president of the United States. Beneath the Department of Defense are th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Melville Gilliss
James Melville Gilliss (September 6, 1811 – February 9, 1865) was an astronomer, United States naval officer and founder of the United States Naval Observatory. Biography Gilliss was born on September 6, 1811 in Georgetown, District of Columbia. His parents were George Gilliss, a federal employee, and Mary (Melville) Gillis. In 1827 at the age of fifteen he joined the navy as a midshipman. He made several training cruises on the ''Delaware'', the ''Java'', and the ''Concord''. In 1833 he passed his examinations and was advanced to passed midshipman.Gould (1866) In 1833 Gilliss requested a leave of absence and began his studies at the University of Virginia. Poor health forced him to leave after six months. He went to Paris for further studies in 1835 and was recalled to Washington to serve as an assistant at the Depot of Charts and Instruments in 1836. In late 1837 he married Rebecca Roberts of Alexandria, D.C. (now Va.). The Depot of Charts and Instruments was headed by Charle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Orientation Parameters
In geodesy and astrometry, earth orientation parameters (EOP) describe irregularities in the rotation of planet Earth. EOP provide the rotational transform from the International Terrestrial Reference System (ITRS) to the International Celestial Reference System (ICRS), or vice versa, as a function of time. Earth's rotational velocity is not constant over time. Any motion of mass in or on Earth causes a slowdown or speedup of the rotation speed, or a change of rotation axis. Small motions produce changes too small to be measured, but movements of very large mass, like sea currents, tides, or those resulting from earthquakes, can produce discernible changes in the rotation and can change very precise astronomical observations. Global simulations of atmosphere, ocean, and land dynamics are used to create effective angular momentum (EAM) functions that can be used to predict changes in EOP. Components Universal time Universal time (UT1) tracks the Earth's rotation in time, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geodesy
Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivalent measurements for other planets (known as '' planetary geodesy''). Geodynamical phenomena, including crustal motion, tides and polar motion, can be studied by designing global and national control networks, applying space geodesy and terrestrial geodetic techniques and relying on datums and coordinate systems. The job title is geodesist or geodetic surveyor. History Definition The word geodesy comes from the Ancient Greek word ''geodaisia'' (literally, "division of Earth"). It is primarily concerned with positioning within the temporally varying gravitational field. Geodesy in the German-speaking world is divided into "higher geodesy" ( or ), which is concerned with measuring Earth on the global scale, and "practical geodes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis M , names sometimes translated to English as "Louis"
{{disambiguation ...
Louis may refer to: * Louis (coin) * Louis (given name), origin and several individuals with this name * Louis (surname) * Louis (singer), Serbian singer * HMS ''Louis'', two ships of the Royal Navy See also Derived or associated terms * Lewis (other) * Louie (other) * Luis (other) * Louise (other) * Louisville (other) * Louis Cruise Lines * Louis dressing, for salad * Louis Quinze, design style Associated names * * Chlodwig, the origin of the name Ludwig, which is translated to English as "Louis" * Ladislav and László - names sometimes erroneously associated with "Louis" * Ludovic, Ludwig, Ludwick, Ludwik Ludwik () is a Polish given name. Notable people with the name include: * Ludwik Czyżewski, Polish WWII general * Ludwik Fleck (1896–1961), Polish medical doctor and biologist * Ludwik Gintel (1899–1973), Polish-Israeli Olympic soccer player ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Branch
John Branch Jr. (November 4, 1782January 4, 1863) was an American politician who served as U.S. Senator, Secretary of the Navy, the 19th Governor of the state of North Carolina, and was the sixth and last territorial governor of Florida. Biography Branch was born in Halifax County, North Carolina, on November 4, 1782, the son of wealthy landowners. Educated at the University of North Carolina, where he was a member of the Philanthropic Society, he occupied himself as a planter and civic leader. Branch served in the North Carolina Senate from 1811 to 1817 and was the state's Governor from 1817 to 1820. After further service in the state Senate, he represented North Carolina in the United States Senate from 1823 until 1829 and was a strong supporter of Andrew Jackson. When Jackson became President, he selected Branch as his Secretary of the Navy. In that post, Branch promoted several reforms in the Navy's policies and administration, many of which were not implemented until yea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Secretary Of The Navy
The secretary of the Navy (or SECNAV) is a statutory officer () and the head (chief executive officer) of the United States Department of the Navy, Department of the Navy, a military department (component organization) within the United States Department of Defense. By law, the secretary of the Navy must civilian control of the military, be a civilian at least five years removed from active military service. The secretary is appointed by the President of the United States, president and requires confirmation by the United States Senate, Senate. The secretary of the Navy was, from its creation in 1798, a member of the president's United States Cabinet, Cabinet until 1949, when the secretary of the Navy (and the secretaries of the United States Secretary of the Army, Army and United States Secretary of the Air Force, Air Force) were by amendments to the National Security Act of 1947 made subordinate to the United States Secretary of Defense, secretary of defense. On August 7, 202 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Quincy Adams
John Quincy Adams (; July 11, 1767 – February 23, 1848) was an American statesman, diplomat, lawyer, and diarist who served as the sixth president of the United States, from 1825 to 1829. He previously served as the eighth United States Secretary of State from 1817 to 1825. During his long diplomatic and political career, Adams also served as an ambassador, and as a member of the United States Congress representing Massachusetts in both chambers. He was the eldest son of John Adams, who served as the second president of the United States from 1797 to 1801, and First Lady Abigail Adams. Initially a Federalist like his father, he won election to the presidency as a member of the Democratic-Republican Party, and in the mid-1830s became affiliated with the Whig Party. Born in Braintree, Massachusetts, Adams spent much of his youth in Europe, where his father served as a diplomat. After returning to the United States, Adams established a successful legal practice in Boston. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
