Planetary Orbits & Ephemerides

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class="fixed-content-margin"></div> </div>  <div id="main_content" tabindex="-1" class="container-fluid hide-tabindex">   <noscript> <div class="alert alert-danger"> <h4>Please enable JavaScript for this website.</h4> <p> This website makes extensive use of JavaScript. The top menus will not function without it and most tools will also not work. </p> <p> If you do not know how to enable JavaScript in your web browser, you should be able find instructions by searching the web for "enable javascript in my browser" (or similar). </p> </div> </noscript> <h1 class="no-top-margin">Planetary Orbits & Ephemerides</h1> <h2>Horizons</h2> <p>The <a href="/horizons/">Horizons</a> service offers comprehensive access to the positions and other information on solar system objects, including the Sun, planets, planetary barycenters, planetary satellites, asteroids, comets, Lagrange Points, selected spacecraft, in a variety of forms and formats. It is the suggested means of obtaining such information for a wide range of analyses. Note that information on Pluto may be found on the <a href="/sats/orbits.html">Planetary Satellites/Orbits</a> page, and that information for known Kuiper Belt Objects (KBOs), such as 486958 Arrokoth (the object investigated by the New Horizons mission, and originally and informally called “Ultima Thule”) may be found by specifying the minor planet designation (which for Arrokoth is 486958) in the <a href="/horizons/">Horizons</a> system.</p> <h2 id="formulae-for-approximate-positions">Formulae for Approximate Positions</h2> <p><a href="/planets/approx_pos.html">Lower accuracy formulae for planetary positions</a> have a number of important applications when one doesn’t need the full accuracy of an integrated ephemeris. Using these formulae with Keplerian elements for the planets provide suitable positions for such applications. Details for using this method are provided on the <a href="/planets/approx_pos.html">Approximate Positions of the Planets</a> page.</p> <h2 id="ephemerides">Ephemerides</h2> <p>The JPL planetary and lunar ephemerides Development Ephemeris (DE) series includes the positions of the Sun, the barycenters of eight planetary systems, the Moon, the Pluto system barycenter, and lunar libration angles, as well as their associated velocities. Ephemerides are generally created to support spacecraft missions to the planets. New ephemerides are generated periodically to include new data and refine the dynamical models.</p> <p>The <a href="eph_export.html">JPL planetary and lunar ephemerides export information</a> file contains a detailed description of the different ephemeris versions available as well as the links from which the ephemeris files can be downloaded. The use of these ephemeris files is recommended only for professionals whose needs are not readily met by the <a href="/horizons/">Horizons system</a>. Alternatively, you may use the <a href="http://naif.jpl.nasa.gov/naif/toolkit.html">NAIF SPICE toolkit</a> and <a href="https://naif.jpl.nasa.gov/naif/data.html">planetary ephemerides</a> in SPK format from JPL’s <a href="http://naif.jpl.nasa.gov/">NAIF website</a>.</p>  <div id="footer" class="container-fluid footer"> <div class="row"> <div class="col-sm-5 col-xs-12"> <img class="ssd-logo" src="/images/ssd_logo.png" alt="SSD Logo" /> </div> <div class="col-sm-3 col-xs-12"> <div class="link-inv"> <a href="/sitemap.html"><i class="fa-fw fa fa-list-alt"></i> Site Map</a> </div> <div class="link-inv"> <a href="https://www.jpl.nasa.gov/caltechjpl-privacy-policies-and-important-notices"><i class="fa-fw fa fa-user-secret"></i> Privacy</a> </div> <div class="link-inv"> <a href="https://www.jpl.nasa.gov/jpl-image-use-policy"><i class="fa-fw fa fa-picture-o"></i> Image Policy</a> </div> </div> <div class="col-sm-4 col-xs-12"> <div class=" link-inv"> <a href="/contact/"><i class="fa-fw fa fa-envelope"></i> Contact Us</a> </div> <div class="text-smaller"> <span class="footer-label text-nowrap">Site Manager:</span> <span class="text-nowrap">Ryan Park</span> </div> <div class="text-smaller2"> <span class="footer-label text-nowrap">Site Design:</span> <span class="text-nowrap">Alan B. 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Planetary Orbits & Ephemerides