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 = 499
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: June 21, 2016 Mars 499 / 4
PHYSICAL DATA (updated 2019-Oct-29):
Vol. mean radius (km) = 3389.92+-0.04 Density (g/cm^3) = 3.933(5+-4)
Mass x10^23 (kg) = 6.4171 Flattening, f = 1/169.779
Volume (x10^10 km^3) = 16.318 Equatorial radius (km)= 3396.19
Sidereal rot. period = 24.622962 hr Sid. rot. rate, rad/s = 0.0000708822
Mean solar day (sol) = 88775.24415 s Polar gravity m/s^2 = 3.758
Core radius (km) = ~1700 Equ. gravity m/s^2 = 3.71
Geometric Albedo = 0.150
GM (km^3/s^2) = 42828.375214 Mass ratio (Sun/Mars) = 3098703.59
GM 1-sigma (km^3/s^2) = +- 0.00028 Mass of atmosphere, kg= ~ 2.5 x 10^16
Mean temperature (K) = 210 Atmos. pressure (bar) = 0.0056
Obliquity to orbit = 25.19 deg Max. angular diam. = 17.9"
Mean sidereal orb per = 1.88081578 y Visual mag. V(1,0) = -1.52
Mean sidereal orb per = 686.98 d Orbital speed, km/s = 24.13
Hill's sphere rad. Rp = 319.8 Escape speed, km/s = 5.027
Perihelion Aphelion Mean
Solar Constant (W/m^2) 717 493 589
Maximum Planetary IR (W/m^2) 470 315 390
Minimum Planetary IR (W/m^2) 30 30 30
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Ephemeris / API_USER Thu May 22 13:29:47 2025 Pasadena, USA / Horizons
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Target body name: Mars (499) {source: mar097}
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 : IAU_MARS {West-longitude positive}
Target radii : 3396.19, 3396.19, 3376.2 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 : Sun
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.250521.p250817
EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-MAY-21. PREDICTS-> 2025-AUG-16
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
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$$SOE
1949-May-20 00:00:00.000, 2433056.708333333, , , 02 50 08.471401, +16 03 44.29141, 2.40493549719993, 3.894200, 1.334, 4.015
1962-Aug-15 11:25:29.198, 2437892.184365723, , , 05 40 44.303057, +23 24 11.95084, 1.76268557371133, 5.313086, 1.094, 4.355
1972-Jul-06 14:44:29.653, 2441505.322565431, , , 08 31 17.495700, +20 08 13.16099, 2.57226408786053, 3.640878, 1.824, 4.354
1974-Mar-27 00:45:17.871, 2442133.739790178, , , 04 57 36.854042, +24 15 31.80997, 1.66790426977500, 5.615011, 1.204, 4.584
1993-Feb-12 20:45:18.307, 2449031.573128554, , , 06 38 59.537729, +26 50 42.56689, 0.79180130229816, 11.82784, -0.526, 4.522
$$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: AU
'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,' =
The targets' approximate apparent visual magnitude and surface brightness.
For planets and natural satellites, output is restricted to solar phase angles
covered by observational data. Outside the observed phase angle range, "n.a."
may be output to avoid extrapolation beyond the limit of model validity.
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. It is
computed only if the target radius is known.
Units: MAGNITUDES & MAGNITUDES PER SQUARE ARCSECOND
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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