Ephemeris
ephemerides /ˌɛfəˈmɛrɪˌdiːz/; from Latin ephemeris 'diary', from Ancient Greek ἐφημερίς (ephēmerís) 'diary, journal')[1][2][3] is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position (and possibly velocity) over time.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.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.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.[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.
Efimerisastronomycelestial navigationAncient Greektrajectoryastronomical objectsartificial satellitespositionvelocityfirst applicationsmechanical computersspherical polar coordinate systemright ascensiondeclinationeclipsesapparent retrograde motionsidereal timenodes of the moonphases of the Mooncelestial bodiesChironastrologersGPS signalsal-KhwārizmīCorpus Christi CollegeAlfonsine tablesBabylonian astronomyPtolemyIbrāhīm al-FazārīMuḥammad ibn Mūsā al-KhwārizmīIbn YunusTables of ToledoIslamic astronomyGerard of CremonaZīj-i ĪlkhānīMaragheh observatoryPrutenic TablesDresden CodexChinesePepysian LibraryRegiomontanusAbraão ben Samuel Zacutomovable typeprinting pressPortugalChristopher ColumbusJohannes StöfflerErasmus ReinholdCopernicusJohannes Stadiusheliocentric modelequantepicyclesTycho BraheRudolphine TablesJohannes KeplerConnaissance des TempsJean PicardOwen GingerichMaestlinMaginiOriganusasteroidscometsnumerical integrationJet Propulsion Laboratory Development EphemerisEphemeride Lunaire Parisiennecelestial mechanicssecular phenomenapublished ephemeridesSolar Systemspacecraftplanetsnatural satellitesgalaxiesequinoxJ2000.0B1950.0Saturnsatellite navigationNautical AlmanacRussian Academy of SciencesObservatoire de ParisAlmanacAmerican Ephemeris and Nautical AlmanacAstronomical AlmanacEphemeraEphemeris timeEpoch (astronomy)Epoch (reference date)Fundamental ephemerisJanuary 0March 0Keplerian elementsOsculating orbitPtolemy's table of chordsTwo-line elementsWilliam of Saint-CloudLiddell, Henry GeorgeScott, RobertA Greek–English LexiconPerseus ProjectMerriam-Webster.com DictionaryBibcodeElsevier BVGeorgij A. KrasinskyVictor A. BrumbergUnited States Naval ObservatoryCambridge University PressHoughton MifflinSpringer-VerlagChronologyArchaeologyGeologyHistoryBig HistoryPaleontologyPeriodsEpochsCalendar erasHuman EraAb urbe conditaAnno DominiCommon EraAnno MundiBosporan era