118 lines
5.5 KiB
Plaintext
118 lines
5.5 KiB
Plaintext
API VERSION: 1.2
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API SOURCE: NASA/JPL Horizons API
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Revised: Apr 22, 2021 Triton / (Neptune) 801
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SATELLITE PHYSICAL PROPERTIES:
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Mean radius (km) = 1352.6 +- 2.4 Mean dens (g cm^-3)= 2.065 +-0.011
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GM (km^3/s^2) = 1428.495 +- 0.62 Geometric Albedo = 0.7
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V(1,0) = -1.24
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SATELLITE ORBITAL DATA (mean values wrt Laplace plane):
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Semi-major axis, a (km) = 354800 Orbital period = 5.876994 d
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Eccentricity, e = 0.000 Rotational period = Synchronous
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Inclination, i (deg) = 157.3
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Fit to all reported measurements through 2020 (Voyager 2, ground, HST)
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Ephemeris / API_USER Thu Aug 14 16:19:50 2025 Pasadena, USA / Horizons
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Target body name: Triton (801) {source: nep097_merged}
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Center body name: Sun (10) {source: nep097_merged}
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Center-site name: BODY CENTER
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Start time : A.D. 2025-Jan-01 00:00:00.0000 TDB
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Stop time : A.D. 2025-Jan-01 00:01:00.0000 TDB
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Step-size : 1 minutes
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Center geodetic : 0.0, 0.0, 0.0 {E-lon(deg),Lat(deg),Alt(km)}
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Center cylindric: 0.0, 0.0, 0.0 {E-lon(deg),Dxy(km),Dz(km)}
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Center radii : 695700.0, 695700.0, 695700.0 km {Equator_a, b, pole_c}
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Output units : AU-D
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Calendar mode : Mixed Julian/Gregorian
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Output type : GEOMETRIC cartesian states
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Output format : 2 (position and velocity)
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Reference frame : Ecliptic of J2000.0
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JDTDB
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X Y Z
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VX VY VZ
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$$SOE
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2460676.500000000 = A.D. 2025-Jan-01 00:00:00.0000 TDB
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X = 2.987802053077272E+01 Y =-6.355569689698364E-01 Z =-6.751627943073906E-01
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VX=-6.787804924900204E-04 VY= 4.636375429506899E-03 VZ= 1.865945736548040E-03
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2460676.500694444 = A.D. 2025-Jan-01 00:01:00.0000 TDB
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X = 2.987802005992279E+01 Y =-6.355537488875286E-01 Z =-6.751614986047274E-01
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VX=-6.772672129266950E-04 VY= 4.637461481841197E-03 VZ= 1.865677756098451E-03
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$$EOE
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TIME
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Barycentric Dynamical Time ("TDB" or T_eph) output was requested. This
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continuous coordinate time is equivalent to the relativistic proper time
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of a clock at rest in a reference frame co-moving with the solar system
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barycenter but outside the system's gravity well. It is the independent
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variable in the solar system relativistic equations of motion.
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TDB runs at a uniform rate of one SI second per second and is independent
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of irregularities in Earth's rotation.
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CALENDAR SYSTEM
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Mixed calendar mode was active such that calendar dates after AD 1582-Oct-15
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(if any) are in the modern Gregorian system. Dates prior to 1582-Oct-5 (if any)
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are in the Julian calendar system, which is automatically extended for dates
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prior to its adoption on 45-Jan-1 BC. The Julian calendar is useful for
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matching historical dates. The Gregorian calendar more accurately corresponds
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to the Earth's orbital motion and seasons. A "Gregorian-only" calendar mode is
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available if such physical events are the primary interest.
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REFERENCE FRAME AND COORDINATES
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Ecliptic at the standard reference epoch
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Reference epoch: J2000.0
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X-Y plane: adopted Earth orbital plane at the reference epoch
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Note: IAU76 obliquity of 84381.448 arcseconds wrt ICRF X-Y plane
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X-axis : ICRF
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Z-axis : perpendicular to the X-Y plane in the directional (+ or -) sense
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of Earth's north pole at the reference epoch.
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Symbol meaning [1 au= 149597870.700 km, 1 day= 86400.0 s]:
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JDTDB Julian Day Number, Barycentric Dynamical Time
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X X-component of position vector (au)
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Y Y-component of position vector (au)
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Z Z-component of position vector (au)
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VX X-component of velocity vector (au/day)
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VY Y-component of velocity vector (au/day)
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VZ Z-component of velocity vector (au/day)
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ABERRATIONS AND CORRECTIONS
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Geometric state vectors have NO corrections or aberrations applied.
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Computations by ...
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Solar System Dynamics Group, Horizons On-Line Ephemeris System
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4800 Oak Grove Drive, Jet Propulsion Laboratory
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Pasadena, CA 91109 USA
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General site: https://ssd.jpl.nasa.gov/
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Mailing list: https://ssd.jpl.nasa.gov/email_list.html
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System news : https://ssd.jpl.nasa.gov/horizons/news.html
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User Guide : https://ssd.jpl.nasa.gov/horizons/manual.html
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Connect : browser https://ssd.jpl.nasa.gov/horizons/app.html#/x
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API https://ssd-api.jpl.nasa.gov/doc/horizons.html
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command-line telnet ssd.jpl.nasa.gov 6775
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e-mail/batch https://ssd.jpl.nasa.gov/ftp/ssd/horizons_batch.txt
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scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS
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Author : Jon.D.Giorgini@jpl.nasa.gov
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