TEST/DEMO FUNCTION: App_Geocent_T_List_Ephem()
App_Geocent_T_List_Ephem (BodyID,TList,TimeZone,TimeScale,DSSTYN,DEGorHMS)
This function returns an apparent geocentric ephemeris for a series of Julian
Dates.
Refresh page for a new random Body ID selection.
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NASA/JPL Body ID = 301
Time Scale = UT
Time Zone = UT-05:00 (Ignored when using TT Scale)
Daylight/Summer Time ? = No
Output DEG or HMS ? = HMS
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List of Julian Dates to be processed:
'2433056.5'
'2437892.184365723'
'2441505.322565431'
'2442133.739790178'
'2449031.573128554'
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API VERSION: 1.2
API SOURCE: NASA/JPL Horizons API
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Revised: July 31, 2013 Moon / (Earth) 301
GEOPHYSICAL DATA (updated 2018-Aug-15):
Vol. mean radius, km = 1737.53+-0.03 Mass, x10^22 kg = 7.349
Radius (gravity), km = 1738.0 Surface emissivity = 0.92
Radius (IAU), km = 1737.4 GM, km^3/s^2 = 4902.800066
Density, g/cm^3 = 3.3437 GM 1-sigma, km^3/s^2 = +-0.0001
V(1,0) = +0.21 Surface accel., m/s^2 = 1.62
Earth/Moon mass ratio = 81.3005690769 Farside crust. thick. = ~80 - 90 km
Mean crustal density = 2.97+-.07 g/cm^3 Nearside crust. thick.= 58+-8 km
Heat flow, Apollo 15 = 3.1+-.6 mW/m^2 Mean angular diameter = 31'05.2"
Heat flow, Apollo 17 = 2.2+-.5 mW/m^2 Sid. rot. rate, rad/s = 0.0000026617
Geometric Albedo = 0.12 Mean solar day = 29.5306 d
Obliquity to orbit = 6.67 deg Orbit period = 27.321582 d
Semi-major axis, a = 384400 km Eccentricity = 0.05490
Mean motion, rad/s = 2.6616995x10^-6 Inclination = 5.145 deg
Apsidal period = 3231.50 d Nodal period = 6798.38 d
Perihelion Aphelion Mean
Solar Constant (W/m^2) 1414+-7 1323+-7 1368+-7
Maximum Planetary IR (W/m^2) 1314 1226 1268
Minimum Planetary IR (W/m^2) 5.2 5.2 5.2
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Ephemeris / API_USER Sat Apr 26 13:25:42 2025 Pasadena, USA / Horizons
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Target body name: Moon (301) {source: DE441}
Center body name: Earth (399) {source: DE441}
Center-site name: GEOCENTRIC
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Start time : A.D. 1949-May-20 00:00:00.0000 UT-05:00
Stop time : A.D. 1993-Feb-13 01:45:18.3071 UT-05:00
Step-size : 0 steps
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Target pole/equ : MOON_ME {East-longitude positive}
Target radii : 1737.4, 1737.4, 1737.4 km {Equator_a, b, pole_c}
Center geodetic : 0.0, 0.0, -6378.137 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.0, 0.0, 0.0 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : ITRF93 {East-longitude positive}
Center radii : 6378.137, 6378.137, 6356.752 km {Equator_a, b, pole_c}
Target primary : Earth
Vis. interferer : MOON (R_eq= 1737.400) km {source: DE441}
Rel. light bend : Sun {source: DE441}
Rel. lght bnd GM: 1.3271E+11 km^3/s^2
Atmos refraction: NO (AIRLESS)
RA format : HMS
Time format : BOTH
Calendar mode : Mixed Julian/Gregorian
Time zone : UT-05:00
EOP file : eop.250425.p250722
EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-APR-25. PREDICTS-> 2025-JUL-21
Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass (>38.000=NO), Daylight (NO )
Table cut-offs 2: Solar elongation ( 0.0,180.0=NO ),Local Hour Angle( 0.0=NO )
Table cut-offs 3: RA/DEC angular rate ( 0.0=NO )
Table format : Comma Separated Values (spreadsheet)
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Date_(ZONE)_HR:MN:SC.fff, Date_________JDUT, , , R.A.____(a-app), DEC_____(a-app), delta, Ang-diam, APmag, S-brt, S-O-T,/r
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$$SOE
1949-May-20 00:00:00.000, 2433056.708333333, , , 22 27 00.762683, -14 07 54.02826, 4.0154961168E+05, 1784.913, -9.833, 5.326, 85.5638,/L
1962-Aug-15 11:25:29.198, 2437892.184365723, , , 21 31 47.570080, -15 43 44.92041, 3.6272705792E+05, 1975.953, -12.752, 3.464, 177.6190,/T
1972-Jul-06 14:44:29.653, 2441505.322565431, , , 03 07 29.628090, +22 32 29.88575, 3.6579710177E+05, 1959.369, -8.533, 5.965, 54.2632,/L
1974-Mar-27 00:45:17.871, 2442133.739790178, , , 02 55 00.916716, +19 44 00.83810, 3.7936653606E+05, 1889.285, -7.658, 6.188, 40.9966,/T
1993-Feb-12 20:45:18.307, 2449031.573128554, , , 14 57 04.070058, -19 37 12.83509, 3.7716181481E+05, 1900.329, -10.440, 5.063, 96.8348,/L
$$EOE
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Column meaning:
TIME
Times PRIOR to 1962 are UT1, a mean-solar time closely related to the
prior but now-deprecated GMT. Times AFTER 1962 are in UTC, the current
civil or "wall-clock" time-scale. UTC is kept within 0.9 seconds of UT1
using integer leap-seconds for 1972 and later years.
Conversion from the internal Barycentric Dynamical Time (TDB) of solar
system dynamics to the non-uniform civil UT time-scale requested for output
has not been determined for UTC times after the next July or January 1st.
Therefore, the last known leap-second is used as a constant over future
intervals.
Time tags refer to the UT time-scale conversion from TDB on Earth
regardless of observer location within the solar system, although clock
rates may differ due to the local gravity field and no analog to "UT"
may be defined for that location.
Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank
(" ") denotes an A.D. date.
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.
NOTE: A time-zone correction has been requested. See header.
NOTE: "n.a." in output means quantity "not available" at the print-time.
'R.A.____(a-app), DEC_____(a-app),' =
Airless apparent right ascension and declination of the target center
with respect to an instantaneous reference frame defined by the Earth equator
of-date (z-axis) and meridian containing the Earth equinox of-date (x-axis
EOP-corrected IAU76/80). Compensated for down-leg light-time delay
gravitational deflection of light, stellar aberration, precession & nutation.
Note: equinox (RA origin) is offset -53 mas from the of-date frame defined
by the IAU06/00a P & N system.
Units: RA in hours-minutes-seconds of time, HH MM SS.ff{ffff}
DEC in degrees-minutes-seconds of arc, sDD MN SC.f{ffff}
'delta,' =
Apparent range ("delta", light-time aberrated) of the target center relative
to the observer. Units: KM
'Ang-diam,' =
The equatorial angular width of the target body full disk, if it were fully
illuminated and visible to the observer. If the target body diameter is unknown
"n.a." is output.
Units: ARCSECONDS
'APmag, S-brt,' =
Moon's approximate apparent visual magnitude and surface brightness. When
phase angle < 7 deg (within ~1 day of full Moon), computed magnitude tends to
be about 0.12 too small.
For Earth-based observers, the estimated dimming due to atmospheric
absorption (extinction) is available as a separate, requestable quantity.
Surface brightness is the average airless visual magnitude of a
square-arcsecond of the illuminated portion of the apparent disk.
Units: MAGNITUDES & MAGNITUDES PER SQUARE ARCSECOND
'S-O-T,/r,' =
Sun-Observer-Target apparent SOLAR ELONGATION ANGLE seen from the observers'
location at print-time.
The '/r' column provides a code indicating the targets' apparent position
relative to the Sun in the observers' sky, as described below:
Case A: For an observing location on the surface of a rotating body, that
body rotational sense is considered:
/T indicates target TRAILS Sun (evening sky: rises and sets AFTER Sun)
/L indicates target LEADS Sun (morning sky: rises and sets BEFORE Sun)
Case B: For an observing point that does not have a rotational model (such
as a spacecraft), the "leading" and "trailing" condition is defined by the
observers' heliocentric ORBITAL motion:
* If continuing in the observers' current direction of heliocentric
motion would encounter the targets' apparent longitude first, followed
by the Sun's, the target LEADS the Sun as seen by the observer.
* If the Sun's apparent longitude would be encountered first, followed
by the targets', the target TRAILS the Sun.
Two other codes can be output:
/* indicates observer is Sun-centered (undefined)
/? Target is aligned with Sun center (no lead or trail)
The S-O-T solar elongation angle is numerically the minimum separation
angle of the Sun and target in the sky in any direction. It does NOT indicate
the amount of separation in the leading or trailing directions, which would
be defined along the equator of a spherical coordinate system.
Units: DEGREES
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/horizons_batch.txt
scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS
Author : Jon.D.Giorgini@jpl.nasa.gov
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