API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: April 12, 2021 Earth Barycenter 3 Dynamical point: --------------- The common point about which the Earth and Moon revolve (center of mass). This is approximately 4671 km from the center of the Earth, or about 3/4 of the way to the surface. See 399 for Earth center, or 301 for Moon center ephemeris. ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Fri May 10 20:37:15 2024 Pasadena, USA / Horizons ******************************************************************************* Target body name: Earth-Moon Barycenter (3) {source: DE441} Center body name: Solar System Barycenter (0) {source: DE441} Center-site name: BODY CENTER ******************************************************************************* Start time : A.D. 2023-Feb-06 00:00:00.0000 TDB Stop time : A.D. 2023-Feb-06 00:00:00.0000 TDB Step-size : DISCRETE TIME-LIST ******************************************************************************* Center geodetic : 0.0, 0.0, 0.0 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 0.0, 0.0, 0.0 {E-lon(deg),Dxy(km),Dz(km)} Center radii : (undefined) Output units : KM-S Calendar mode : Mixed Julian/Gregorian Output type : GEOMETRIC cartesian states Output format : 3 (position, velocity, LT, range, range-rate) Reference frame : Ecliptic of J2000.0 ******************************************************************************* JDTDB X Y Z VX VY VZ LT RG RR ******************************************************************************* $$SOE 2459981.500000000 = A.D. 2023-Feb-06 00:00:00.0000 TDB X =-1.085163786984627E+08 Y = 1.013179988055772E+08 Z = 2.700260926970094E+04 VX=-2.094954957400336E+01 VY=-2.177165376161352E+01 VZ= 1.309956439897064E-03 LT= 4.952179110768877E+02 RG= 1.484625948073656E+08 RR= 4.547199298247665E-01 $$EOE ******************************************************************************* TIME Barycentric Dynamical Time ("TDB" or T_eph) output was requested. This continuous coordinate time is equivalent to the relativistic proper time of a clock at rest in a reference frame co-moving with the solar system barycenter but outside the system's gravity well. It is the independent variable in the solar system relativistic equations of motion. TDB runs at a uniform rate of one SI second per second and is independent of irregularities in Earth's rotation. CALENDAR SYSTEM Mixed calendar mode was active such that calendar dates after AD 1582-Oct-15 (if any) are in the modern Gregorian system. Dates prior to 1582-Oct-5 (if any) are in the Julian calendar system, which is automatically extended for dates prior to its adoption on 45-Jan-1 BC. The Julian calendar is useful for matching historical dates. The Gregorian calendar more accurately corresponds to the Earth's orbital motion and seasons. A "Gregorian-only" calendar mode is available if such physical events are the primary interest. REFERENCE FRAME AND COORDINATES Ecliptic at the standard reference epoch Reference epoch: J2000.0 X-Y plane: adopted Earth orbital plane at the reference epoch Note: IAU76 obliquity of 84381.448 arcseconds wrt ICRF X-Y plane X-axis : ICRF Z-axis : perpendicular to the X-Y plane in the directional (+ or -) sense of Earth's north pole at the reference epoch. Symbol meaning: JDTDB Julian Day Number, Barycentric Dynamical Time X X-component of position vector (km) Y Y-component of position vector (km) Z Z-component of position vector (km) VX X-component of velocity vector (km/sec) VY Y-component of velocity vector (km/sec) VZ Z-component of velocity vector (km/sec) LT One-way down-leg Newtonian light-time (sec) RG Range; distance from coordinate center (km) RR Range-rate; radial velocity wrt coord. center (km/sec) ABERRATIONS AND CORRECTIONS Geometric state vectors have NO corrections or aberrations applied. Computations by ... Solar System Dynamics Group, Horizons On-Line Ephemeris System 4800 Oak Grove Drive, Jet Propulsion Laboratory Pasadena, CA 91109 USA General site: https://ssd.jpl.nasa.gov/ Mailing list: https://ssd.jpl.nasa.gov/email_list.html System news : https://ssd.jpl.nasa.gov/horizons/news.html User Guide : https://ssd.jpl.nasa.gov/horizons/manual.html Connect : browser https://ssd.jpl.nasa.gov/horizons/app.html#/x API https://ssd-api.jpl.nasa.gov/doc/horizons.html command-line telnet ssd.jpl.nasa.gov 6775 e-mail/batch https://ssd.jpl.nasa.gov/ftp/ssd/hrzn_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov *******************************************************************************