The International Celestial Reference System ( ICRS ) is based on hundreds of extra-galactic radio sources, mostly quasars, distributed around the entire sky.

UT1 is the same everywhere on Earth, and is proportional to the rotation angle of the Earth with respect to distant quasars, specifically, the International Celestial Reference Frame ( ICRF ), neglecting some small adjustments.

The International Earth Rotation and Reference Systems Service ( IERS ), formerly the International Earth Rotation Service, is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter ( EOP ) and International Celestial Reference System ( ICRS ) groups.

* International Celestial Reference System

* International Celestial Reference Frame

* International Celestial Reference Frame of the IERS

* International Celestial Reference System

* International Celestial Reference Frame

* International Celestial Reference System, or ICRS-U. S.

Due in part to its radio luminosity and its discovery as the first identified quasar, 3C 273's right ascension in the Fifth Fundamental Catalog ( FK5 ) is used to standardize the positions of 23 extragalactic radio sources used to define the International Celestial Reference System ( ICRS ).

The Hipparcos and Tycho Catalogues were then constructed such that the Hipparcos reference frame coincides, to within observational uncertainties, with the International Celestial Reference System ( the ICRS ), and representing the best estimates at the time of the catalogue completion ( in 1996 ).

: Aya's distant cousin and director of C-Project ( Celestial Project ) conducted by Mikage International.

* International Celestial Reference System

In 2009 the acronym " MHO ", for Molecular Hydrogen emission-line Object, was approved for these objects by the International Astronomical Union Working Group on Designations, and has been entered into their on-line Reference Dictionary of Nomenclature of Celestial Objects.

* The International Celestial Reference Frame -- a reference frame in astrometry and astronomy

* International Celestial Reference Frame

de: International Celestial Reference System

fr: International Celestial Reference System

Its measurement by several observatories is coordinated by the International Earth Rotation and Reference Systems Service ( IERS ).

International geodetic organizations like the IERS ( International Earth Rotation and Reference Systems Service ) speak of a reference system.

Such a frame is, e. g., WGS84, or the frames that are regularly produced and published by the International Earth Rotation and Reference Systems Service ( IERS ).

The Encyclopedia Americana: The International Reference Work New York: Americana Corp., 1963.

One of the most widely used models is the International Reference Ionosphere ( IRI ) ( IRI 2007 ), which is based on data and specifies the four parameters just mentioned.

The International Earth Rotation and Reference Systems Service can insert or remove leap seconds from the last day of any month ( June and December are preferred ).

The NIST Reference on Constants, Units, and Uncertainty: International System of Units ( SI ) ( web site ):

Yet the International Earth Rotation and Reference Systems Service and the International Astronomical Union have defined a framework called the International Terrestrial Reference System.

* International Earth Rotation and Reference Systems Service

The rotation of the Earth and UT are monitored by the International Earth Rotation and Reference Systems Service ( IERS ).

Modern geodetic reference systems, such as the World Geodetic System and the International Terrestrial Reference Frame, use a single Earth-centered oblate spheroid.

The longer " true " sidereal period is called a stellar day by the International Earth Rotation and Reference Systems Service ( IERS ).

The IERS Reference Meridian ( IRM ), also called the International Reference Meridian, is the reference meridian used as the prime meridian ( 0 ° longitude ) by the International Earth Rotation and Reference Systems Service ( IERS ).

In the International System of Units ( SI ), the standard unit of area is the square metre ( written as m < sup > 2 </ sup >), which is the area of a square whose sides are one metre long.

In general, the International System of Units only uses capital letters for the symbols of units which are named after individual scientists, while au or a. u.

As the speed of light in meters per second ( c < sub > 0 </ sub >) is fixed in the International System of Units, this measurement of the speed of light in AU / d ( c < sub > AU </ sub >) also determines the value of the astronomical unit in meters ( A ):

In the International System of Units ( SI ), B is the symbol of the bel, a unit of logarithmic power ratios named after Alexander Graham Bell.

In most other contexts, the industry uses kilo, mega, giga, etc., in a manner consistent with their meaning in the International System of Units ( SI ): as powers of 1000.

Along with giga-or G -, meaning, they are now known as SI prefixes after the International System of Units ( SI ), introduced in 1960 to formalize aspects of the metric system.

The International System of Units does not define units for digital information but notes that the SI prefixes may be applied outside the contexts where base units or derived units would be used.

The Usenet System, ITCA Teleconferencing Yearbook 1993, ITCA Research Committee, International Teleconferencing Association, Washington, DC.

The International Bureau of Weights and Measures (), is an international standards organisation, one of three such organisations established to maintain the International System of Units ( SI ) under the terms of the Metre Convention ( Convention du Mètre ).

: International: Landing points for the MAYA-1, Eastern Caribbean Fiber System, and the Cayman-Jamaica Fiber System submarine cables that provide links to the US and parts of Central and South America.

Membership in International Organizations: The major organizations in which Colombia is a member include: the Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean, Andean Pact, Caribbean Development Bank, Economic Commission for Latin America and the Caribbean, Food and Agriculture Organization of the United Nations, Group of 3, Group of 11, Group of 24, Group of 77, Inter-American Development Bank, International Atomic Energy Agency, International Bank for Reconstruction and Development, International Chamber of Commerce, International Civil Aviation Organization, International Criminal Police Organization, International Development Association, International Finance Corporation, International Fund for Agricultural Development, International Labour Organization, International Maritime Organization, International Maritime Satellite Organization, International Monetary Fund ( IMF ), International Olympic Committee, International Organization for Migration, International Organization for Standardization, International Telecommunication Union, International Telecommunications Satellite Organization, International Trade Union Confederation, Latin American Economic System, Latin American Integration Association, Latin Union, Non-Aligned Movement, Organization of American States ( OAS ), Permanent Court of Arbitration, Rio Group, United Nations ( UN ), UN Conference on Trade and Development, UN Educational, Scientific and Cultural Organization, UN Industrial Development Organization, UN Office of the High Commissioner for Refugees, Universal Postal Union, World Confederation of Labour, World Federation of Trade Unions, World Health Organization, World Intellectual Property Organization, World Meteorological Organization, World Tourism Organization, and World Trade Organization.