need to distinguish between astronomical tables and computed ephemerides, see Talk Ephemeris astronomical tables distinct from ephemeris cleanup needed to avoid confusing astrological uses with astronomical File Ephemeris 1790.png thumb The title page Ephimeris , the first Greek newspaper, printed in Vienna from 1790 to 1797. An ephemeris plural ephemerides from the Greek language Greek word ... first applications of mechanical computers , an ephemeris will still often be a simple printed ... noon or midnight . An astronomical ephemeris may also provide data on astronomical phenomena ... to form the standard European ephemeris until the Alfonsine tables. 13th century the Zij i Ilkhani ... European ephemeris until the Prutenic Tables almost 300 years later. 1408 Chinese astronomy Chinese Ephemeris Table copy in Pepysian Library, Cambridge, UK refer book 1434 Chinese tables believed ... predicted a lunar eclipse for the natives, using the Ephemeris of the German astronomer ... Tables of Johannes Kepler became the new standard. Scientific ephemeris For scientific uses, a modern planetary ephemeris comprises software that generates positions of the planets and often of their satellites ... inclination of its ring. An ephemeris is usually only correct for a particular location on the Earth ... ephemeris data consisting of health and exact location data that GPS receivers then use together ... ephemeris The majority of astrologers study tropical astrology , involving planetary positions ... has been geocentric , heliocentric astrology is an emerging field for this purpose a standard ephemeris ... Ephemeris and Nautical Almanac old name Ephemeris time Epoch astronomy Epoch reference date January 0 or March 0 Jet Propulsion Laboratory Development Ephemeris DE400 Secular variations of the planetary .... 1990 , IAU SYMP.141 P.189, 1989. cite book first Hugh last MacCraig title The 200 Year Ephemeris ... book first Neil F. last Michelsen title The American Ephemeris for the 21st Century 2001 to 2100 at Midnight ... more details
The term ephemeris time often abbreviated ET can in principle refer to time in connection with any Astronomical Ephemeris astronomical ephemeris . In practice it has been used more specifically to refer ... theory see below Definition of ephemeris time 1952 Definition of ephemeris time 1952 . Ephemeris ... a modern relativistic coordinate time scale, implemented by the Jet Propulsion Laboratory JPL ephemeris ... them is the DE405 ephemeris in widespread current use. The time scale represented by T sub eph ... Time TCB time scale currently adopted as a standard by the IAU see below JPL ephemeris time argument Teph JPL ephemeris time argument Teph . ref name EMS1998 refEMS1998 E M Standish 1998 . ref Most of the following sections relate to the ephemeris time of the 1952 standard. An impression has sometimes arisen that ephemeris time was in use from 1900 this probably arose because ET, though proposed ... ESAE 1961 Explanatory Supplement 1961 , esp. pages 69 and 87. ref The ephemeris time of the 1952 standard leaves a continuing legacy, through its ephemeris second which became closely duplicated ... of the second . History of ephemeris time 1952 standard Ephemeris time ET , adopted as standard in 1952 ... , for example for use in ephemeris ephemerides of the Sun as observed from the Earth , the Moon, and the planets ... ephemeris time . ref name ESAAp79 refESAA ESAA 1992 , see http books.google.com books?id uJ4JhGJANb4C ... be designated ephemeris time , and gave Clemence s formula see Definition of ephemeris time 1952 Definition of ephemeris time 1952 for translating mean solar time to ephemeris time. The International ..., p.9 also refClem1971 Clemence 1971 . ref Practical introduction took some time see Use of ephemeris time in official almanacs and ephemerides Use of ephemeris time in official almanacs and ephemerides ephemeris time ET remained a standard until superseded in the 1970s by further time scales see Revision of time scales Revision . During the currency of ephemeris time as a standard, the details ... more details
The American Ephemeris and Nautical Almanac was published for the years 1855 to 1980, containing information necessary for astronomers, surveyors, and navigators. It was based on the original British publication, The Nautical Almanac and Astronomical Ephemeris , with which it merged to form Astronomical Almanac The Astronomical Almanac , published from the year 1981 to the present. History Authorized by Congress in 1849, the American Nautical Almanac Office was founded and attached to the Department of the Navy . The American Ephemeris and Nautical Almanac was first published in 1852, containing data for the year 1855. Its data was originally calculated by human computers , such as Chauncey Wright and Joseph Winlock astronomer Joseph Winlock . Between 1855 and 1881 it had two parts, the first for the Prime Meridian meridian of Greenwich contained data on the Sun , Moon , lunar distance navigation lunar distances , Venus , Mars , Jupiter , and Saturn , which was published separately as The American Nautical Almanac . The second part contained data for the Washington meridian meridian of Washington ... Nautical Almanac ceased to be a reprint of the first part of the American Ephemeris and Nautical Almanac , becoming a separately prepared volume for the navigator. In 1937, the American Ephemeris ... Majesty s Nautical Almanac Office but published separately within The American Ephemeris and Nautical Almanac and The Astronomical Ephemeris , a new name for the old British title The Nautical Almanac and Astronomical Ephemeris . Beginning in 1981, the title The American Ephemeris and Nautical Almanac and the British title The Astronomical Ephemeris were completely merged under the single title ... Ephemeris generic article Almanac generic article Nautical almanac generic article The Nautical ... Ephemeris and the American Ephemeris and Nautical Almanac , 1961 ESAE 1961 , a joint ... books Category Maritime books ca American Ephemeris and Nautical Almanac sk American Ephemeris ... more details
astronomy stub The name Jet Propulsion Laboratory Development Ephemeris followed by a number , or its abbreviation JPL DE number , designates one of a series of numbered versions of the astronomical ephemerides produced at the Jet Propulsion Laboratory in Pasadena, California , primarily for purposes of space navigation and astronomy. Some versions of these ephemerides are or have been in official use for example, the Astronomical Almanac issues for 1984 onwards through 2002 were based on JPL ephemeris DE200 , and for 2003 onwards the Astronomical Almanac has been based on JPL ephemeris DE405 . ref See US Naval Observatory Naval Oceanography Portal , http www.usno.navy.mil USNO astronomical applications publications hist astro almanac History of the Astronomical Almanac accessed December 2009 also emsiom1998 E M Standish 1998 for details of DE405 and article DE400 . ref Each such ephemeris was initially produced by numerical integration of equations of motion, including the effects not only of gravitational accelerations and relativistic corrections, but also tidal and figure effects and a model of the lunar librations. ref For example, the equations of motion for DE102 are documented in nsw1983 Newhall, Standish, & Williams 1983 , at pages 151 153. ref The time argument of the integrated ephemerides is a relativistic coordinate time scale designated Ephemeris time JPL ephemeris time argument Teph T sub eph sub . ref See sources cited at Ephemeris time JPL ephemeris time argument Teph JPL ephemeris time argument Teph . ref The resulting ephemeris data are stored or distributed in the form of a system of numerical coefficients for Chebyshev polynomials which can be used to recover ... of observations. The observational data included in the fits by which each ephemeris is produced has ... 49M.PDF 1978 79 LS47 A DSN station location set compatible with JPL Development Ephemeris DE108 . ref ... ephemeris of the moon and planets spanning forty four centuries , Astronomy and Astrophysics ISSN ... more details
JPL Horizons On Line Ephemeris System provides easy access to key solar system data and flexible production of highly accurate ephemerides for solar system objects. Osculating orbit Osculating elements at a given Epoch astronomy epoch are always an approximation to an object s orbit i.e. an unperturbed conic orbit or a Two body problem two body orbit . The real orbit or the best approximation to such considers Perturbation astronomy perturbations by all planets, a few of the List of notable asteroids larger asteroids , a few other physical usually small forces, and requires numerical integration . JPL ephemerides do not use things such as periods, eccentricities, etc. ref name jpl ssd faq cite web date 2006 02 28 title Frequently Asked Questions FAQ What s the exact value of... publisher JPL Solar System Dynamics author Alan B. Chamberlin url http ssd.jpl.nasa.gov ?faq B06 accessdate 2011 01 20 ref Instead, JPL integrates the equations of motion in Cartesian coordinate system Cartesian coordinates x,y,z , and adjusts the initial conditions in order to fit modern, highly accurate measurements of planetary positions. ref name jpl ssd faq Introduction There are 3 ways to use the system WWW Email Telnet See also Jet Propulsion Laboratory References Reflist External links http ssd.jpl.nasa.gov ?horizons JPL Horizons On Line Ephemeris System http ssd.jpl.nasa.gov ?horizons doc HORIZONS User Manual astronomy stub Category Astrometry zh ... more details
Nautical Almanac can refer to Nautical almanac a publication describing the positions and movements of celestial bodies American Ephemeris and Nautical Almanac first published in 1852 U.S. Nautical Almanac, part of the American Ephemeris and Nautical Almanac since 1958 The Nautical Almanac , the nautical almanac published by HM Nautical Almanac Office in the United Kingdom Nautical Almanac band an altered electronics noise music band disambig ... more details
The Astronomical Almanac ref Special Booksources 0118873377 Astronomical Almanac for the Year 2007, United States Naval Observatory Nautical Almanac Office, 2006 . ref is an almanac published by the United States Naval Observatory and Her Majesty s Nautical Almanac Office , containing solar system ephemeris and catalogs of selected stellar and extragalactic objects. The Explanatory Supplement to the Astronomical Almanac provides detailed discussion of usage and data reduction methods used by the Almanac ref name Seidelmann Special Booksources 0935702687 P. K. Seidelmann editor , Explanatory Supplement to the Astronomical Almanac University Science Books, New York, 1992 . ref . Publication history The Astronomical Almanac is the direct descendant of the British and American navigational almanacs. The British Nautical Almanac and Astronomical Ephemeris had been published since 1766, and was renamed The Astronomical Ephemeris in 1960. The American Ephemeris and Nautical Almanac had been published since 1852. In 1981 the British and American publications were combined under the title The Astronomical Almanac . ref http aa.usno.navy.mil publications docs asa history.php History of the Astronomical Almanac . United States Naval Observatory. ref See also American Ephemeris and Nautical Almanac specific title Astronomical Ephemeris generic article Almanac generic article Nautical almanac generic article The Nautical Almanac familiar name for a specific series of official British publications which appeared under a variety of different full titles for the period 1767 to 1959, as well as being a specific official title jointly UK US published for 1960 onwards ref name Seidelmann ref Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac , 1961 ESAE 1961 , a joint publication of the Nautical Almanac Offices of the UK and USA esp. sect.1B. ref References references External links http asa.usno.navy.mil The Astronomical Almanac Onlin ... more details
January 0 is an alternate name for December 31 . In an ephemeris January 0 refers to the day before January 1 in an annual ephemeris . It keeps the date in the year for which the ephemeris was published, thus avoiding any reference to the previous year, even though it is the same day as December 31 of the previous year. January 0 occurs in the epoch for the second History ephemeris second , 1900 January 0 at 12 hours ephemeris time . ref name USNO cite web title Leap Seconds publisher Time Service Department, United States Naval Observatory url http tycho.usno.navy.mil leapsec.html accessdate 2006 12 31 ref 1900 January 0 at Greenwich Mean Noon was also the epoch used by Newcomb s Tables of the Sun , which became the epoch for the Julian day Alternatives Dublin Julian day . ref http textfiles.poboxes.info computers DOCUMENTATION astroclk.dc2 ASTROCLK Astronomical Clock and Celestial Tracking Program page 110 ref In technology In Microsoft Excel , the day 0 of the Epoch reference date Computing 1900 date format is January 0, 1900. ref name m cite web url http support.microsoft.com kb 205719 publisher Microsoft title XL2000 Early Dates on Office Spreadsheet Component Differ from Excel accessdate 2007 12 08 quote In the Microsoft Office Spreadsheet Component, the value 0 evaluates to the date December 30, 1899 and the value 1 evaluates to December 31, 1899. ... In Excel, the value 0 evaluates to January 0, 1900 and the value 1 evaluates to January 1, 1900. ref See also commons Ephemeris February 30 February 31 March 0 System time References Reflist months Category January January 00 Category December ca 0 de gener es 0 de enero fr 0 janvier gl 0 de xaneiro gu hi hr 0. sije nja id 0 Januari ml 0 mr arz 0 ja 1 0 sh 0.1. sv 0 januari tl Enero 0 ta 0 ur 0 zh 1 0 ... more details
unreferenced date June 2007 orphan date January 2009 In astrology , the adjusted calculation date , or artificial birthday is the day on which the planetary position shown in an Ephemeris coincides with the progressed positions of the planets and other bodies in the heavens. The adjusted calculation date remains the same from year to year and is used by astrologers when they want to cast a progressed horoscope for a person. Category Technical factors of astrology astrology stub ... more details
wiktionary Jed Jed can refer to Jed given name Jed album Jed album , by the Goo Goo Dolls Jed Water , river in Scotland JED may mean JED, IATA code for King Abdulaziz International Airport at Jeddah, Saudi Arabia Julian Ephemeris Date, a.k.a. Julian Date JED text editor disambig fr JED it JED pl Jed sk Jed rozli ovacia str nka ... more details
A projection of the orbit of the Moon onto the ecliptic plane, as seen from the geocentre. Also plotted is the centre of curvature of the trajectory it s the large splotch near the centre and the Earth itself, that small circle nearby. Data for 2006, taken from the JPL DE 405 ephemeris. PD self date December 2006 Please do not include this image in any wikipedia article unless you know what you are doing it was uploaded specifically for Talk Moon commentary about the article on the Moon . Consult with User mdf for advice. ... more details
JPL stands for Jet Propulsion Laboratory, a NASA facility in Pasadena, California. JPL may also refer to JPL cyclecar , built in 1913 JPL Horizons On Line Ephemeris System , in astronomy Jacksonville Public Library Florida , the library system for Jacksonville, Florida Jasper Park Lodge , a hotel in Alberta, Canada Jon Peter Lewis , an American Idol singer songwriter Jefferson Parish Library , the public library system of Jefferson Parish, Louisiana disambig it JPL nl JPL ja JPL ... more details
30 June 2007 ref ref name ESAE ESAE 1961 Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac prepared jointly by the Nautical Almanac Offices of the United ..., The Nautical Almanac and Astronomical Ephemeris contained both astro navigational and general astronomical ... for 1767 to 1833 gave their ephemeris tabulations in terms of Greenwich apparent not mean time ... and Astronomical Ephemeris containing the astro navigational data was also published separately as The Nautical Almanac & Astronomical Ephemeris, Part 1 . For 1914 1951 the former Part 1 after redesign ... and unified as to content between the UK and USA, under the titles in UK The Astronomical Ephemeris ... Ephemeris was the use of ephemeris time in place of mean solar time for the major ephemeris ... Nautical Almanac in the USA In the USA, an official and initially separate series of ephemeris publications began with the issue for 1855 as The American Ephemeris and Nautical Almanac but before ... and Astronomical Ephemeris for 1804, e.g. at https library.mysticseaport.org initiative ImPage.cfm?PageNum ... 2010 ref See also American Ephemeris and Nautical Almanac specific title Astronomical Almanac specific title Astronomical Ephemeris generic article Almanac generic article Nautical almanac generic article ... more details
W. Foulsham & Company Limited is a British publisher founded by William Foulsham in 1819. http www.foulsham.com page100.htm It is the current publisher of Old Moore s Almanack , an annual publication first published in 1697, and of Raphael s Ephemeris , which Robert Thomas Cross acquired in the 1870s and edited until his death in 1913. Reflist External links official http www.foulsham.com UK publish company stub Category Book publishing companies of the United Kingdom ... more details
Unreferenced date July 2007 Robert Thomas Cross b. 15 May 1850 in Worstead , d. 1923 was a British astrologer . Cross was one in a series of editors of Raphael s Ephemeris , started by Robert Cross Smith in 1827, who all took the pseudonym Raphael . Robert Thomas Cross is often confused with Robert Cross Smith due to the similarity in name and the identical pseudonym. Life Cross was originally named Frederick Robert Cross, but dropped the Frederick . He began studying astrology quite young and by the age of twenty five, already married with two sons, he was teaching astrology and accepting clients, and soon became the editor of The Prophetic Messenger , which he renamed to Raphael s Ephemeris . In the 1870s he obtained the copyright to Raphael s Ephemeris, which the Cross family then owned until 1985 when it was sold to W. Foulsham & Co,the Publisher. In Raphael s Ephemeris for 1913 he wrote Nothing has prospered with me except astrology...I have succeeded beyond my expectations... In 1893, Cross s almanac sold 200,000 copies. His Guide to Astrology , published in two volumes in 1877 and 1879 was widely used by astrologers for many years. In 1895 the Astrologer s Magazine quoted Cross for his support of the idea of forming an astrological society. On 14 January 1896 Alan Leo founded a society with himself as the first president and Cross as vice president. Raphael s Ephemeris continues to be published, with W. Foulsham & Company Limited . External links http books.google.com books?id CikSAAAAYAAJ A Description of the Faces and Degrees of the Zodiac as Given in the Ancient Authors, Being Applicable to Genethliacal and Horary Astrology by Raphael http books.google.com books?id JvUYAAAAYAAJ Raphael s Private Instructions in Genethliacal Astrology by Raphael handwritten copy http books.google.com books?id dxYCAAAAYAAJ The Book of Fate Whereby All Questions May Be Answered Respecting the Present and Future by Raphael The Guide to Astrology by Raphael http books.google.co ... more details
to the non relativistic former standard of ephemeris time adopted by the IAU in 1952 and superseded ..., for practical astronomical purposes, to the long established Ephemeris time JPL ephemeris time argument Teph JPL ephemeris time argument T sub eph sub as implemented in Jet Propulsion Laboratory Development Ephemeris JPL Development Ephemeris DE405 ref http www.iau.org static resolutions IAU2006 ... every 86400 seconds of TCB . History See also Ephemeris time History of ephemeris time 1952 standard Ephemeris time History for further information and sources. From the 17th century to the late .... Ephemeris time was consequently developed as a standard that was free from the irregularities ... clock was invented, such clocks were used increasingly from the late 1950s as Ephemeris time Implementations Secondary realizations using atomic clocks secondary realizations of ephemeris time ET . These secondary ... clocks, and e.g. in the late 1960s they were used to provide standard time for planetary ephemeris ... dynamical in that connection. Use of TDB TDB is a successor of Ephemeris Time ET , in that ET ... to TDB as well as to Terrestrial Time TT see Ephemeris time Implementations Ephemeris ... more details
orphan date December 2008 The Berliner Astronomisches Jahrbuch abbrev. B.A.J. is an astronomical ephemeris almanac and the longest publication series in astronomy . It was a compendium of ephemerides of all large Solar system bodies and of fundamental stars which define the celestial reference system. The B.A.J. series began in 1776 and continued until 1960 when it was included into the international edition of the Astronomical Ephemeris and of Apparent Places of Fundamental Stars APFS . This merger was decided in 1959 by the International Astronomical Union IAU . At least the Yearbook had a volume of about 500 pages starting in 1907 it contained accurate apparent places of the first international fundamental catalogue which was compiled for astrometry later these data were actualized within the framework of the Catalogues of Fundamental Stars FK3 and FK4 . In the 1940s the Almanac was edited in co operation with the Astronomisch Geod tisches Jahrbuch of the Astronomisches Recheninstitut Recheninstitut in Heidelberg , Germany, which was merged also into the IAU editions like other national almanacs. External links http www.ari.uni heidelberg.de publikationen baj Astrononomisches Rechen Institut Heidelberg Astronomisches Rechen Institut ARI http www.ari.uni heidelberg.de publikationen baj baj1776 baj1776.htm Edition sseite der ersten Ausgabe 1774 Category Astronomical Almanac Category Astrometry de Berliner Astronomisches Jahrbuch sk Berliner Astronomisches Jahrbuch ... more details
This is a projection of the Moon s orbit about the Sun onto the ecliptic plane. Also included is the Earth as you can see, it s hard to tell them apart at this resolution. Further plots are the centre of curvature for the trajectory of the Moon and Earth. The large spiky one is the Moon, and the almost unresolved dot near the centre is the Earth. Data for the year 2006, and was taken from the JPL DE 405 ephemeris. PD self date December 2006 Please do not include this image in any wikipedia article unless you know what you are doing it was uploaded specifically for Talk Moon commentary about the article on the Moon . Contact User mdf for advice. ... more details
For a general view on the Greek term, see Ephemeris File Ephemeris 1790.png thumb The title page of an ephemeris from 1790. Ephimeris lang el is the oldest surviving ref The issues of a newspaper published by the Zakynthos Zakynthian George Bendotis in June July of 1784 in Vienna are no longer extant. ref Greek language newspaper printed from 1790 to 1797, in Vienna . ref http www.e telescope.gr el history and archaeology 159 first greek newspaper ref History In 1790, the Greek typographers Poulios Markidis Pouliou and Georgios Markidis Pouliou, from Siatista , started publishing the newspaper in the Greek, Serbian Illyrian and German languages, after successfully negotiating a license from the Austrian Empire Austrian authorities. Vienna , the Austrian capital, was that time an important commercial center for Greek merchants. The newspaper published the Declaration of the Rights of Man and of the Citizen in serials, as well as several works by Rigas Feraios . The newspaper s run lasted until 1797, when Georgios Pouliou was arrested along with Rigas Feraios for their publication of revolutionary and godless works, and the paper was shut down in January 1798. ref K nstantinos D maras. http books.google.com books?id p3GHlQL9mbAC&pg PA162&dq ephimeris 2B1790 2Bgreek 2Bvienna&lr &as brr 3&hl el&cd 1 v onepage&q ephimeris 2B1790 2Bgreek 2Bvienna&f false A history of modern Greek literature. SUNY Press, 1972. ISBN 9780873950718, p. 162 ref Many of its original issues can be seen in various public libraries in Greece , and in 2000, the Academy of Athens modern Academy of Athens reprinted a collected edition of the newspaper. References reflist Sources gr icon cite web last Matsou first Katerina title 1790 1797 work publisher date 2006 06 18 url http www.e telescope.gr gr cat05 art05 060818.htm format doi ... Category Newspapers published in Greece Category Greek Enlightenment Greece stub de Ephemeris el ... more details
oneref date December 2010 Time To First Fix TTFF is a measure of the time required for a GPS receiver to acquire satellite signals and navigation data, and calculate a position solution called a Fix position fix . File ConstellationGPS.gif thumb right 240px An animation depicting the orbits of GPS satellites in medium earth orbit. Scenarios The TTFF is commonly broken down into three more specific scenarios, as defined in the GPS equipment guide Cold or Factory The receiver is missing, or has inaccurate estimates of, its position, velocity, the time, or the visibility of any of the GPS satellites. As such, the receiver must systematically search for all possible satellites. After acquiring a satellite signal, the receiver can begin to obtain approximate information on all the other satellites, called the GPS signals almanac . This almanac is transmitted repeatedly over 12.5 minutes. Almanac data can be received from any of the GPS satellites and is considered valid for up to 180 days. Manufacturers typically claim the factory TTFF to be 15 minutes. Warm or Normal The receiver has estimates of the current time within 20 seconds, the current position within 100 kilometers, and its velocity within 25 m s, and it has valid almanac data. It must acquire each satellite signal and obtain that satellite s detailed orbital information, called GPS signals ephemeris data. Each satellite broadcasts its ephemeris data every 30 seconds, and is valid for up to four hours. Hot or standby The receiver has valid time, position, almanac, and ephemeris data, enabling a rapid acquisition of satellite signals. The time required of a receiver in this state to calculate a position fix may also be termed Time to Subsequent fix TTSF Many receivers can use as many as twelve channels simultaneously, allowing quicker fixes. ref http www.gpsinformation.org dale why12.htm GPS information site Why twelve channels? ref See also Global Positioning System GPS GPS signals High Sensitivity GPS Referenc ... more details
and adopted by the IAU in 1952 see Ephemeris time History of ephemeris time 1952 standard Ephemeris ... motion of the Sun by Simon Newcomb , 1895, as retrospectively used in the definition of ephemeris time ... January 0 at 12 hours ephemeris time. Caesium atomic clocks became operational in 1955, and their use ... of time interval. After three years of comparisons with lunar observations it was determined that the ephemeris ... measurement result for the ephemeris second see Ephemeris time Redefinition of the second Ephemeris time redefinition of the second . In 1976 , however, the International Astronomical Union IAU resolved that the theoretical basis for ephemeris time was wholly non relativistic, and therefore, beginning in 1984 ephemeris time would be replaced by two further time scales with allowance ... more details
scale irregularities, and this was confirmed in the early twentieth century. ref See Ephemeris time History of ephemeris time 1952 standard Ephemeris time history , and sources shown there. ref Time ... 1952 onwards by an ephemeris time standard based on the Earth s orbital period and in practice on the motion ... in Earth s rotation. Time standards for planetary motion calculations Ephemeris time and its successor ... scales. Ephemeris time Ephemeris Time Ephemeris time ET was from 1952 to 1976 an official time scale ... motion of the Earth around the Sun, from which the ephemeris second was derived as a defined fraction of the tropical year. This ephemeris second was the standard for the SI second from 1956 to 1967 ... Essen L Essen , J V L Parry 1958 , Frequency of caesium in terms of ephemeris time , Phys Rev Letters ... and Geophysics , IAU Symposia 128 1988 , at pp 413 418. ref This Ephemeris Time standard was non relativistic ... almanacs for 1984 and after, by numerically integrated Jet Propulsion Laboratory Development Ephemeris DE200 based on the JPL relativistic coordinate time scale Ephemeris time JPL ephemeris time argument ... Ephemeris Time and maintained continuity with it. TDT is a uniform atomic time scale, whose unit ... from Ephemeris Time to TDT. TDT has since been redefined as Terrestrial Time TT . Barycentric ... more details
1968 160, 874 5 ref that the JPL Ephemeris Tape System was used for virtually all computations of spacecraft trajectories in the US space program , and that it had, as its current lunar ephemeris, an evaluation of the Improved Lunar Ephemeris incorporating a number of corrections sources are named as The Improved Lunar Ephemeris documentation which was the report of the Eckert computations carried ... Lunar Ephemeris , US Government Printing Office, 1954 . ref with corrections as described by Eckert ... Ephemeris 1968 US Government Printing Office, 1966 ref Taken together, the corrections ... more details
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