数値計算屋さんの雑記，メモ．
HP：https://ssd.jpl.nasa.gov/horizons/
telnet:
$ telnet horizons.jpl.nasa.gov 6775
telnetでの使い方の例．太陽（@10）を原点としたときの地球（399）の位置と速度．座標系はICRFである．
JPL Horizons, version 4.97
Type '?' for brief help, '?!' for details,
'-' for previous prompt, 'x' to exit
System news updated August 26, 2023
Horizons> 399
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Revised: April 12, 2021 Earth 399
GEOPHYSICAL PROPERTIES (revised May 9, 2022):
Vol. Mean Radius (km) = 6371.01+-0.02 Mass x10^24 (kg)= 5.97219+-0.0006
Equ. radius, km = 6378.137 Mass layers:
Polar axis, km = 6356.752 Atmos = 5.1 x 10^18 kg
Flattening = 1/298.257223563 oceans = 1.4 x 10^21 kg
Density, g/cm^3 = 5.51 crust = 2.6 x 10^22 kg
J2 (IERS 2010) = 0.00108262545 mantle = 4.043 x 10^24 kg
g_p, m/s^2 (polar) = 9.8321863685 outer core = 1.835 x 10^24 kg
g_e, m/s^2 (equatorial) = 9.7803267715 inner core = 9.675 x 10^22 kg
g_o, m/s^2 = 9.82022 Fluid core rad = 3480 km
GM, km^3/s^2 = 398600.435436 Inner core rad = 1215 km
GM 1-sigma, km^3/s^2 = 0.0014 Escape velocity = 11.186 km/s
Rot. Rate (rad/s) = 0.00007292115 Surface area:
Mean sidereal day, hr = 23.9344695944 land = 1.48 x 10^8 km
Mean solar day 2000.0, s = 86400.002 sea = 3.62 x 10^8 km
Mean solar day 1820.0, s = 86400.0 Love no., k2 = 0.299
Moment of inertia = 0.3308 Atm. pressure = 1.0 bar
Mean surface temp (Ts), K= 287.6 Volume, km^3 = 1.08321 x 10^12
Mean effect. temp (Te), K= 255 Magnetic moment = 0.61 gauss Rp^3
Geometric albedo = 0.367 Vis. mag. V(1,0)= -3.86
Solar Constant (W/m^2) = 1367.6 (mean), 1414 (perihelion), 1322 (aphelion)
HELIOCENTRIC ORBIT CHARACTERISTICS:
Obliquity to orbit, deg = 23.4392911 Sidereal orb period = 1.0000174 y
Orbital speed, km/s = 29.79 Sidereal orb period = 365.25636 d
Mean daily motion, deg/d = 0.9856474 Hill's sphere radius = 234.9
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Select ... [E]phemeris, [F]tp, [M]ail, [R]edisplay, ?, <cr>: E
Observe, Elements, Vectors [o,e,v,?] : v
Coordinate center [ <id>,coord,geo ] : @10
Reference plane [eclip, frame, body ] : eclip
Starting TDB [>= 9999BC-Mar-21 00:01] : 2023-09-01
Ending TDB [<= 9999-Dec-30 12:00] : 2023-09-02
Output interval [ex: 10m, 1h, 1d, ? ] : 1d
Current output table defaults --
Ref. Frame = ICRF
Corrections = NONE
Units = AU-D
CSV format = NO
Output delta-T = NO
Table type = 3 (position, velocity, LT, range, range-rate)
Vector label = YES
Accept default output [ cr=(y), n, ?] : n
Output reference frame [ ICRF, B1950] : ICRF
Corrections [ 1=NONE, 2=LT, 3=LT+S ] : 1
Output units [1=KM-S, 2=AU-D, 3=KM-D] : 3
Spreadsheet CSV format [ YES, NO ] : YES
Output delta-T (TDB-UT) [ YES, NO ] : YES
Select output table type [ 1-6, ? ] : 3
Working ... -
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Ephemeris / PORT_LOGIN Thu Aug 31 22:00:37 2023 Pasadena, USA / Horizons
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Target body name: Earth (399) {source: DE441}
Center body name: Sun (10) {source: DE441}
Center-site name: BODY CENTER
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Start time : A.D. 2023-Sep-01 00:00:00.0000 TDB
Stop time : A.D. 2023-Sep-02 00:00:00.0000 TDB
Step-size : 1440 minutes
*******************************************************************************
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 : 696000.0, 696000.0, 696000.0 km {Equator_a, b, pole_c}
Output units : KM-D
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, Calendar Date (TDB), delta-T, X, Y, Z, VX, VY, VZ,
**************************************************************************************************************************************************************************************************************************
$$SOE
2460188.500000000, A.D. 2023-Sep-01 00:00:00.0000, 69.182648, 1.400066731258702E+08, -5.656864340673850E+07, 2.358117319162935E+03, 9.220286795888582E+05, 2.375474361150964E+06, -2.180159483080331E+02, 5.8297
2460189.500000000, A.D. 2023-Sep-02 00:00:00.0000, 69.182631, 1.409086515169136E+08, -5.418515162005703E+07, 2.133538944859058E+03, 8.818795576669943E+05, 2.391408949941805E+06, -2.301151491271014E+02, 5.8284
$$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 [1 day=86400.0 s]:
JDTDB Julian Day Number, Barycentric Dynamical Time
del_T Time-scale conversion difference TDB - UT (s)
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/day)
VY Y-component of velocity vector (km/day)
VZ Z-component of velocity vector (km/day)
LT One-way down-leg Newtonian light-time (day)
RG Range; distance from coordinate center (km)
RR Range-rate; radial velocity wrt coord. center (km/day)
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
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>>> Select... [A]gain, [N]ew-case, [F]tp, [M]ail, [R]edisplay, ? : ^[OB^[OB^[OB^[OB^[OB^[OB^[OB^[OB^[OB^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[B^[[Bq
>>> Select... [A]gain, [N]ew-case, [F]tp, [M]ail, [R]edisplay, ? : q
___ _____ ___
/_ /| /____/ \ /_ /| Horizons On-line Ephemeris System v4.97
| | | | __ \ /| | | | Solar System Dynamics Group
___| | | | |__) |/ | | |__ Jet Propulsion Laboratory
/___| | | | ___/ | |/__ /| Pasadena, CA, USA
|_____|/ |_|/ |_____|/
Connection closed by foreign host.