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Ephemeris

February 16, 2024

For the 18th-century Greek newspaper, see Efimeris.
For the ephemerides of Alexander the Great, see Historiography_of_Alexander_the_Great § Ephemerides_of_Alexander_the_Great.

In astronomy and celestial navigation, an ephemeris (/ɪˈfɛmərəs/; pl. ephemerides /ˌɛfəˈmɛrədiːz/; from Latin ephemeris 'diary', and Greek ἐφημερίς (ephemeris) 'diary, journal')[1][2][3] is a book with tables that gives the trajectory of naturally occurring astronomical objects as well as artificial satellites in the sky, i.e., the position (and possibly velocity) over time. Historically, positions were given as printed tables of values, given at regular intervals of date and time. The calculation of these tables was one of the first applications of mechanical computers. Modern ephemerides are often provided in electronic form. However, printed ephemerides are still produced, as they are useful when computational devices are not available.

The astronomical position calculated from an ephemeris is often given in the spherical polar coordinate system of right ascension and declination, together with the distance from the origin if applicable. Some of the astronomical phenomena of interest to astronomers are eclipses, apparent retrograde motion/planetary stations, planetary ingresses, sidereal time, positions for the mean and true nodes of the moon, the phases of the Moon, and the positions of minor celestial bodies such as Chiron.

Ephemerides are used in celestial navigation and astronomy. They are also used by astrologers.[4] GPS signals include ephemeris data used to calculate the position of satellites in orbit.

History edit

 
A Latin translation of al-Khwārizmī's zīj, page from Corpus Christi College MS 283
 
Alfonsine tables
 
Page from Almanach Perpetuum

Modern ephemeris edit

For scientific uses, a modern planetary ephemeris comprises software that generates positions of planets and often of their satellites, asteroids, or comets, at virtually any time desired by the user.

After introduction of computers in the 1950s it became feasible to use numerical integration to compute ephemerides. The Jet Propulsion Laboratory Development Ephemeris is a prime example. Conventional so-called analytical ephemerides that utilize series expansions for the coordinates have also been developed, but of much increased size and accuracy as compared to the past, by making use of computers to manage the tens of thousands of terms. Ephemeride Lunaire Parisienne and VSOP are examples.

Typically, such ephemerides cover several centuries, past and future; the future ones can be covered because the field of celestial mechanics has developed several accurate theories. Nevertheless, there are secular phenomena which cannot adequately be considered by ephemerides. The greatest uncertainties in the positions of planets are caused by the perturbations of numerous asteroids, most of whose masses and orbits are poorly known, rendering their effect uncertain. Reflecting the continuing influx of new data and observations, NASA's Jet Propulsion Laboratory (JPL) has revised its published ephemerides nearly every year since 1981.[8]

Solar System ephemerides are essential for the navigation of spacecraft and for all kinds of space observations of the planets, their natural satellites, stars, and galaxies.

Scientific ephemerides for sky observers mostly contain the positions of celestial bodies in right ascension and declination, because these coordinates are the most frequently used on star maps and telescopes. The equinox of the coordinate system must be given. It is, in nearly all cases, either the actual equinox (the equinox valid for that moment, often referred to as "of date" or "current"), or that of one of the "standard" equinoxes, typically J2000.0, B1950.0, or J1900. Star maps almost always use one of the standard equinoxes.

Scientific ephemerides often contain further useful data about the moon, planet, asteroid, or comet beyond the pure coordinates in the sky, such as elongation to the Sun, brightness, distance, velocity, apparent diameter in the sky, phase angle, times of rise, transit, and set, etc. Ephemerides of the planet Saturn also sometimes contain the apparent inclination of its ring.

Celestial navigation serves as a backup to Satellite navigation. Software is widely available to assist with this form of navigation; some of this software has a self-contained ephemeris.[9] When software is used that does not contain an ephemeris, or if no software is used, position data for celestial objects may be obtained from the modern Nautical Almanac or Air Almanac.[10]

An ephemeris is usually only correct for a particular location on the Earth. In many cases, the differences are too small to matter. However, for nearby asteroids or the Moon, they can be quite important.

Other modern ephemerides recently created are the EPM (Ephemerides of Planets and the Moon), from the Russian Institute for Applied Astronomy of the Russian Academy of Sciences,[11] and the INPOP (Intégrateur numérique planétaire de l'Observatoire de Paris) by the French IMCCE.[12][13]

See also edit

Notes edit

  1. ^ ἐφημερίς. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.
  2. ^ "ephemeris". Merriam-Webster.
  3. ^ "ephemeris". Dictionnaire Gaffiot latin-français.
  4. ^ Gingerich, Owen (2017). Arias, Elisa Felicitas; Combrinck, Ludwig; Gabor, Pavel; Hohenkerk, Catherine; Seidelmann, P. Kenneth (eds.). "The Role of Ephemerides from Ptolemy to Kepler". The Science of Time 2016. Astrophysics and Space Science Proceedings. Cham: Springer International Publishing. 50: 17–24. Bibcode:2017ASSP...50...17G. doi:10.1007/978-3-319-59909-0_3. ISBN 978-3-319-59909-0.
  5. ^ Jones, S.S.D.; Howard, John; William, May; Logsdon, Tom; Anderson, Edward; Richey, Michael. "Navigation". Encyclopedia Britannica. Encyclopædia Britannica, inc. Retrieved 13 March 2019.
  6. ^ Hoskin, Michael (28 November 1996). The Cambridge Illustrated History of Astronomy. Cambridge University Press. p. 89. ISBN 9780521411585.
  7. ^ Gingerich, Owen (1975). ""Crisis" versus Aesthetic in the Copernican Revolution" (PDF). Vistas in Astronomy. Elsevier BV. 17 (1): 85–95. Bibcode:1975VA.....17...85G. doi:10.1016/0083-6656(75)90050-1. S2CID 20888261. Retrieved 23 June 2016.
  8. ^ Georgij A. Krasinsky and Victor A. Brumberg, Secular Increase of Astronomical Unit from Analysis of the Major Planet Motions, and its Interpretation Celestial Mechanics and Dynamical Astronomy 90: 267–288, (2004).
  9. ^ American Practical Navigator: An Epitiome of Navigation. Bethesda, MD: National Imagery and Mapping Agency. 2002. p. 270.
  10. ^ . United States Naval Observatory. Archived from the original on 27 January 2022. Retrieved 11 November 2016.
  11. ^ Pitjeva, Elena V. (August 2006). "The dynamical model of the planet motions and EPM ephemerides". Highlights of Astronomy. 2 (14): 470. Bibcode:2007HiA....14..470P. doi:10.1017/S1743921307011453.
  12. ^ "INPOP10e, a 4-D planetary ephemeris". IMCCE. Retrieved 2 May 2013.
  13. ^ Viswanathan, V.; Fienga, A.; Gastineau, M.; Laskar, J. (1 August 2017). "INPOP17a planetary ephemerides". Notes Scientifiques et Techniques de l'Institut de Mécanique Céleste. 108: 108. Bibcode:2017NSTIM.108.....V. doi:10.13140/RG.2.2.24384.43521.

References edit

  • Duffett-Smith, Peter (1990). Astronomy With Your Personal Computer. Cambridge University Press. ISBN 0-521-38995-X.
  • "ephemeris". American Heritage Dictionary of the English Language (3rd ed.). Boston: Houghton Mifflin. 1992.
  • MacCraig, Hugh (1949). The 200 Year Ephemeris. Macoy Publishing Company.
  • Meeus, Jean (1991). Astronomical Algorithms. Willmann-Bell. ISBN 0-943396-35-2.
  • Michelsen, Neil F. (1990). Tables of Planetary Phenomena. ACS Publications, Inc. ISBN 0-935127-08-9.
  • Michelsen, Neil F. (1982). The American Ephemeris for the 21st Century - 2001 to 2100 at Midnight. Astro Computing Services. ISBN 0-917086-50-3.
  • Montenbruck, Oliver (1989). Practical Ephemeris Calculations. Springer-Verlag. ISBN 0-387-50704-3.
  • Seidelmann, Kenneth (2006). Explanatory supplement to the astronomical almanac. University Science Books. ISBN 1-891389-45-9.

External links edit

 
Wikimedia Commons has media related to Ephemeris.
  • The JPL HORIZONS online ephemeris
  • (archived 26 February 2005)
  • "Ephemerides-IMCEE".

February 16, 2024
ephemeris, 18th, century, greek, newspaper, efimeris, ephemerides, alexander, great, historiography, alexander, great, ephemerides, alexander, great, astronomy, celestial, navigation, ephemeris, ephemerides, from, latin, ephemeris, diary, greek, ἐφημερίς, ephe. For the 18th century Greek newspaper see Efimeris For the ephemerides of Alexander the Great see Historiography of Alexander the Great Ephemerides of Alexander the Great In astronomy and celestial navigation an ephemeris ɪ ˈ f ɛ m e r e s pl ephemerides ˌ ɛ f e ˈ m ɛ r e d iː z from Latin ephemeris diary and Greek ἐfhmeris ephemeris diary journal 1 2 3 is a book with tables that gives the trajectory of naturally occurring astronomical objects as well as artificial satellites in the sky i e the position and possibly velocity over time Historically positions were given as printed tables of values given at regular intervals of date and time The calculation of these tables was one of the first applications of mechanical computers Modern ephemerides are often provided in electronic form However printed ephemerides are still produced as they are useful when computational devices are not available The astronomical position calculated from an ephemeris is often given in the spherical polar coordinate system of right ascension and declination together with the distance from the origin if applicable Some of the astronomical phenomena of interest to astronomers are eclipses apparent retrograde motion planetary stations planetary ingresses sidereal time positions for the mean and true nodes of the moon the phases of the Moon and the positions of minor celestial bodies such as Chiron Ephemerides are used in celestial navigation and astronomy They are also used by astrologers 4 GPS signals include ephemeris data used to calculate the position of satellites in orbit Contents 1 History 2 Modern ephemeris 3 See also 4 Notes 5 References 6 External linksHistory edit nbsp A Latin translation of al Khwarizmi s zij page from Corpus Christi College MS 283 nbsp Alfonsine tables nbsp Page from Almanach Perpetuum1st millennium BC Ephemerides in Babylonian astronomy 2nd century AD the Almagest and the Handy Tables of Ptolemy 8th century AD the zij of Ibrahim al Fazari 9th century AD the zij of Muḥammad ibn Musa al Khwarizmi 12th century AD the Tables of Toledo based largely on Arabic zij sources of Islamic astronomy were edited by Gerard of Cremona to form the standard European ephemeris until the Alfonsine Tables 13th century AD the Zij i ilkhani Ilkhanic Tables were compiled at the Maragheh observatory in Persia 13th century AD the Alfonsine Tables were compiled in Spain to correct anomalies in the Tables of Toledo remaining the standard European ephemeris until the Prutenic Tables almost 300 years later 13th century AD the Dresden Codex an extant Mayan ephemeris 1408 Chinese ephemeris table copy in Pepysian Library Cambridge UK refer book 1434 Chinese tables believed known to Regiomontanus 1474 Regiomontanus publishes his day to day Ephemerides in Nurnberg Germany 5 1496 the Almanach Perpetuum of Abraao ben Samuel Zacuto one of the first books published with a movable type and printing press in Portugal 1504 While shipwrecked on the island of Jamaica Christopher Columbus successfully predicted a lunar eclipse for the natives using the ephemeris of the German astronomer Regiomontanus 6 1531 Work of Johannes Stoffler is published posthumously at Tubingen extending the ephemeris of Regiomontanus through 1551 1551 the Prutenic Tables of Erasmus Reinhold were published based on Copernicus s theories 1554 Johannes Stadius published Ephemerides novae et auctae the first major ephemeris computed according to Copernicus heliocentric model using parameters derived from the Prutenic Tables Although the Copernican model provided an elegant solution to the problem of computing apparent planetary positions it avoided the need for the equant and better explained the apparent retrograde motion of planets it still relied on the use of epicycles leading to some inaccuracies for example periodic errors in the position of Mercury of up to ten degrees One of the users of Stadius s tables is Tycho Brahe 1627 the Rudolphine Tables of Johannes Kepler based on elliptical planetary motion became the new standard 1679 La Connaissance des Temps ou calendrier et ephemerides du lever amp coucher du Soleil de la Lune amp des autres planetes first published yearly by Jean Picard and still extant 1975 Owen Gingerich using modern planetary theory and digital computers calculates the actual positions of the planets in the 16th century and graphs the errors in the planetary positions predicted by the ephemerides of Stoffler Stadius and others According to Gingerich the error patterns are as distinctive as fingerprints and reflect the characteristics of the underlying tables That is the error patterns for Stoffler are different from those of Stadius but the error patterns of Stadius closely resemble those of Maestlin Magini Origanus and others who followed the Copernican parameters 7 Modern ephemeris editFor scientific uses a modern planetary ephemeris comprises software that generates positions of planets and often of their satellites asteroids or comets at virtually any time desired by the user After introduction of computers in the 1950s it became feasible to use numerical integration to compute ephemerides The Jet Propulsion Laboratory Development Ephemeris is a prime example Conventional so called analytical ephemerides that utilize series expansions for the coordinates have also been developed but of much increased size and accuracy as compared to the past by making use of computers to manage the tens of thousands of terms Ephemeride Lunaire Parisienne and VSOP are examples Typically such ephemerides cover several centuries past and future the future ones can be covered because the field of celestial mechanics has developed several accurate theories Nevertheless there are secular phenomena which cannot adequately be considered by ephemerides The greatest uncertainties in the positions of planets are caused by the perturbations of numerous asteroids most of whose masses and orbits are poorly known rendering their effect uncertain Reflecting the continuing influx of new data and observations NASA s Jet Propulsion Laboratory JPL has revised its published ephemerides nearly every year since 1981 8 Solar System ephemerides are essential for the navigation of spacecraft and for all kinds of space observations of the planets their natural satellites stars and galaxies Scientific ephemerides for sky observers mostly contain the positions of celestial bodies in right ascension and declination because these coordinates are the most frequently used on star maps and telescopes The equinox of the coordinate system must be given It is in nearly all cases either the actual equinox the equinox valid for that moment often referred to as of date or current or that of one of the standard equinoxes typically J2000 0 B1950 0 or J1900 Star maps almost always use one of the standard equinoxes Scientific ephemerides often contain further useful data about the moon planet asteroid or comet beyond the pure coordinates in the sky such as elongation to the Sun brightness distance velocity apparent diameter in the sky phase angle times of rise transit and set etc Ephemerides of the planet Saturn also sometimes contain the apparent inclination of its ring Celestial navigation serves as a backup to Satellite navigation Software is widely available to assist with this form of navigation some of this software has a self contained ephemeris 9 When software is used that does not contain an ephemeris or if no software is used position data for celestial objects may be obtained from the modern Nautical Almanac or Air Almanac 10 An ephemeris is usually only correct for a particular location on the Earth In many cases the differences are too small to matter However for nearby asteroids or the Moon they can be quite important Other modern ephemerides recently created are the EPM Ephemerides of Planets and the Moon from the Russian Institute for Applied Astronomy of the Russian Academy of Sciences 11 and the INPOP Integrateur numerique planetaire de l Observatoire de Paris by the French IMCCE 12 13 See also editAlmanac American Ephemeris and Nautical Almanac The Astronomical Almanac new name Ephemera Ephemeris time Epoch astronomy Epoch reference date Fundamental ephemeris January 0 or March 0 Keplerian elements Nautical almanac Osculating orbit Ptolemy s table of chords Two line elements William of Saint CloudNotes edit ἐfhmeris Liddell Henry George Scott Robert A Greek English Lexicon at the Perseus Project ephemeris Merriam Webster ephemeris Dictionnaire Gaffiot latin francais Gingerich Owen 2017 Arias Elisa Felicitas Combrinck Ludwig Gabor Pavel Hohenkerk Catherine Seidelmann P Kenneth eds The Role of Ephemerides from Ptolemy to Kepler The Science of Time 2016 Astrophysics and Space Science Proceedings Cham Springer International Publishing 50 17 24 Bibcode 2017ASSP 50 17G doi 10 1007 978 3 319 59909 0 3 ISBN 978 3 319 59909 0 Jones S S D Howard John William May Logsdon Tom Anderson Edward Richey Michael Navigation Encyclopedia Britannica Encyclopaedia Britannica inc Retrieved 13 March 2019 Hoskin Michael 28 November 1996 The Cambridge Illustrated History of Astronomy Cambridge University Press p 89 ISBN 9780521411585 Gingerich Owen 1975 Crisis versus Aesthetic in the Copernican Revolution PDF Vistas in Astronomy Elsevier BV 17 1 85 95 Bibcode 1975VA 17 85G doi 10 1016 0083 6656 75 90050 1 S2CID 20888261 Retrieved 23 June 2016 Georgij A Krasinsky and Victor A Brumberg Secular Increase of Astronomical Unit from Analysis of the Major Planet Motions and its Interpretation Celestial Mechanics and Dynamical Astronomy 90 267 288 2004 American Practical Navigator An Epitiome of Navigation Bethesda MD National Imagery and Mapping Agency 2002 p 270 Almanacs and Other Publications Naval Oceanography Portal United States Naval Observatory Archived from the original on 27 January 2022 Retrieved 11 November 2016 Pitjeva Elena V August 2006 The dynamical model of the planet motions and EPM ephemerides Highlights of Astronomy 2 14 470 Bibcode 2007HiA 14 470P doi 10 1017 S1743921307011453 INPOP10e a 4 D planetary ephemeris IMCCE Retrieved 2 May 2013 Viswanathan V Fienga A Gastineau M Laskar J 1 August 2017 INPOP17a planetary ephemerides Notes Scientifiques et Techniques de l Institut de Mecanique Celeste 108 108 Bibcode 2017NSTIM 108 V doi 10 13140 RG 2 2 24384 43521 References editDuffett Smith Peter 1990 Astronomy With Your Personal Computer Cambridge University Press ISBN 0 521 38995 X ephemeris American Heritage Dictionary of the English Language 3rd ed Boston Houghton Mifflin 1992 MacCraig Hugh 1949 The 200 Year Ephemeris Macoy Publishing Company Meeus Jean 1991 Astronomical Algorithms Willmann Bell ISBN 0 943396 35 2 Michelsen Neil F 1990 Tables of Planetary Phenomena ACS Publications Inc ISBN 0 935127 08 9 Michelsen Neil F 1982 The American Ephemeris for the 21st Century 2001 to 2100 at Midnight Astro Computing Services ISBN 0 917086 50 3 Montenbruck Oliver 1989 Practical Ephemeris Calculations Springer Verlag ISBN 0 387 50704 3 Seidelmann Kenneth 2006 Explanatory supplement to the astronomical almanac University Science Books ISBN 1 891389 45 9 External links edit nbsp Wikimedia Commons has media related to Ephemeris The JPL HORIZONS online ephemeris Introduction to the JPL ephemerides archived 26 February 2005 Ephemerides IMCEE Portals nbsp Astronomy nbsp Stars nbsp Spaceflight nbsp Outer space nbsp Solar System Retrieved from https en wikipedia org w index php title Ephemeris amp oldid 1195708809, wikipedia, wiki, book, books, library,

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