Basic Planetocentric Ephemeris Calculator and Data Query Portal Built Around The NASA/JPL Horizons API v1.0 - by Jay Tanner

NASA/JPL Target Body ID # or Record # of Body Being Observed or Enter a Special Data Query or Command Directive INFO

NASA/JPL Central Body ID# Where Observer is Located This Could Be Earth or Another Planet (Excluding Asteroids)

Output DEG or HMS

Daylight/Summer Time?

Reference System

START: Calendar Date and Time             Time Zone :          Time Scale

STOP: Calendar Date and Time

Step Size

View/Copy PHP Source Code

Double-Click Within Text Area to Select ALL Text ################################################################################ ################################################################################ BASIC PLANETOCENTRIC EPHEMERIS CALCULATOR Built Around The NASA/JPL Horizons API ------------------------------------------------------------------------------ NASA/JPL CENTRAL BODY ID# WHERE OBSERVER IS LOCATED or SPECIAL DIRECTIVE 399 ------------------------------------------------------------------------------ NASA/JPL BODY ID# OF BODY BEING OBSERVED FROM THE BODY SPECIFIED ABOVE Moon (301) {source: DE441} ------------------------------------------------------------------------------ OBSERVER LOCATION / CALENDAR DATE RANGE / TIME / ZONE / STEP SIZE Base Time Scale = UT Time Zone Offset = UT-05:00 +Positive = East Daylight / Summer Time = No Start Date/Time = AD 2025-Jan-01 00:00:00 Stop Date/Time = AD 2025-Jan-15 00:00:01 Ephemeris Step Size = 1 day ------------------------------------------------------------------------------ Angular Output Mode = HMS Reference System = ICRF ################################################################################ ################################################################################ THIS IS THE CENTRAL BODY FROM WHICH THE OBSERVATION IS BEING MADE API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* 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 ******************************************************************************* ################################################################################ ################################################################################ THIS IS THE PLANETOCENTRIC EPHEMERIS FOR THE TARGET BODY BEING OBSERVED OR THE RESULT RETURNED FOR A SPECIAL QUERY OR DIRECTIVE: API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* 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 ******************************************************************************** ******************************************************************************* Ephemeris / API_USER Sat Jan 4 15:13:58 2025 Pasadena, USA / Horizons ******************************************************************************* Target body name: Moon (301) {source: DE441} Center body name: Earth (399) {source: DE441} Center-site name: GEOCENTRIC ******************************************************************************* Start time : A.D. 2025-Jan-01 00:00:00.0000 UT-05:00 Stop time : A.D. 2025-Jan-15 00:00:01.0000 UT-05:00 Step-size : 1440 minutes ******************************************************************************* 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 : CAL Calendar mode : Gregorian Time zone : UT-05:00 EOP file : eop.250103.p250401 EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-JAN-03. PREDICTS-> 2025-MAR-31 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) ********************************************************************************************************************************************* Date_(ZONE)_HR:MN:SS, , , R.A.____(a-app), DEC_____(a-app), delta, deldot, Ang-diam, APmag, S-brt, Cnst, S-O-T,/r ********************************************************************************************************************************************* $$SOE 2025-Jan-01 00:00:00, , , 19 58 48.773975, -25 14 02.44431, 3.8104383947E+05, -0.0383530, 1880.968, -5.659, 6.217, Sgr, 16.3121,/T 2025-Jan-02 00:00:00, , , 20 55 28.461699, -21 22 54.12523, 3.7798194660E+05, -0.0323965, 1896.206, -6.758, 6.330, Cap, 28.4958,/T 2025-Jan-03 00:00:00, , , 21 49 31.630573, -16 20 04.79138, 3.7545559408E+05, -0.0260808, 1908.965, -7.716, 6.155, Cap, 41.0613,/T 2025-Jan-04 00:00:00, , , 22 41 10.015512, -10 24 35.11012, 3.7346727508E+05, -0.0200181, 1919.128, -8.536, 5.901, Aqr, 53.8284,/T 2025-Jan-05 00:00:00, , , 23 31 10.525127, -03 56 15.46144, 3.7198068836E+05, -0.0144812, 1926.798, -9.234, 5.634, Aqr, 66.7260,/T 2025-Jan-06 00:00:00, , , 00 20 40.064628, +02 45 19.29584, 3.7095191137E+05, -0.0093781, 1932.141, -9.829, 5.376, Psc, 79.7114,/T 2025-Jan-07 00:00:00, , , 01 10 54.029872, +09 20 37.34303, 3.7035836688E+05, -0.0043271, 1935.238, -10.343, 5.130, Psc, 92.7543,/T 2025-Jan-08 00:00:00, , , 02 03 06.689969, +15 29 19.62407, 3.7021740116E+05, 0.0011829, 1935.975, -10.792, 4.891, Ari, 105.8281,/T 2025-Jan-09 00:00:00, , , 02 58 18.630600, +20 49 40.52096, 3.7058897343E+05, 0.0075930, 1934.034, -11.193, 4.654, Ari, 118.9020,/T 2025-Jan-10 00:00:00, , , 03 56 57.332429, +24 59 00.67791, 3.7156108380E+05, 0.0150836, 1928.974, -11.559, 4.409, Tau, 131.9334,/T 2025-Jan-11 00:00:00, , , 04 58 34.127329, +27 36 33.79356, 3.7322122301E+05, 0.0234495, 1920.393, -11.899, 4.152, Tau, 144.8588,/T 2025-Jan-12 00:00:00, , , 06 01 34.312897, +28 28 27.11656, 3.7562124004E+05, 0.0320773, 1908.123, -12.219, 3.880, Tau, 157.5656,/T 2025-Jan-13 00:00:00, , , 07 03 41.349296, +27 32 32.96446, 3.7874530420E+05, 0.0400381, 1892.384, -12.515, 3.599, Gem, 169.6608,/T 2025-Jan-14 00:00:00, , , 08 02 49.752872, +24 59 28.15964, 3.8248998395E+05, 0.0462677, 1873.857, -12.617, 3.482, Cnc, 174.4067,/L 2025-Jan-15 00:00:00, , , 08 57 48.833013, +21 08 35.48336, 3.8666180005E+05, 0.0497804, 1853.639, -12.322, 3.734, Cnc, 163.9584,/L $$EOE ********************************************************************************************************************************************* 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 Calendar dates are given in the modern Gregorian system, extended prior to its 1582-Oct-15 adoption. The Gregorian calendar more closely corresponds to physical Earth seasons and orbital motion, but can differ by up to 10 days with historical records made under the prior Julian calendar, more if the Julian calendar was extended prior to its 45-Jan-1 BC adoption to label the historical event. Select "mixed" calendar mode if correlation with historical dates prior to A.D. 1582 is important. 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, deldot,' = Apparent range ("delta", light-time aberrated) and range-rate ("delta-dot") of the target center relative to the observer. A positive "deldot" means the target center is moving away from the observer, negative indicates movement toward the observer. Units: KM and KM/S '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 'Cnst,' = Constellation ID; the 3-letter abbreviation for the name of the constellation containing the target centers' astrometric position as defined by IAU (1930) boundary delineation. See documentation for list of abbreviations. '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/hrzn_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov *********************************************************************************************************************************************

Double-Click Within Text Area to Select ALL Text ############################################################################## Planetocentric Ephemeris Calculator + Basic NASA/JPL Data Query Portal Built Around the NASA/JPL Horizons API AUTHOR : Jay Tanner - 2025 LANGUAGE : PHP v7.4.9 This program allows you to move around the solar system and get an idea of what it looks like (numerically) from other perspectives. The numbers it returns can be used in extended computations beyond Horizons. For example, the program can help to answer questions like: If we were on Mars, where would Earth appear to be among the stars? If we were on Pluto, how much fainter would the sun appear from there as opposed to as viewed from Earth? etc. Generally, what the program does, is simply generate a basic planetocentric ephemeris as viewed from the central body. In the case of the Earth, it would generate an apparent geocentric ephemeris. If the central body was Mars (499), then it would be called an areocentric ephemeris, or an ephem- eris as computed for the center of Mars instead of Earth. To accomodate any planet in general, the generic term 'planetocentric' may be used. We can easily move around the solar system and view it numerically from many different perspectives very quickly and easily with this program. ================================ USAGE AS A JPL DATA QUERY PORTAL The program can also be used to look up physical data on the all the planets and their moons and thousands of asteroids and comets. It can also look up data on past, present, future proposed missions and also data on the space telescopes, numerous spacecraft and vehicles such as Rovers. The program interface emulates some of the features of the NASA/JPL TelNet connection (telnet://horizons.jpl.nasa.gov:6775) but not all of them. However, students of NASA/JPL can use this program as a quick solar system traveling ephemeris calculator and general data lookup tool and learn how to access the Horizons API via PHP by examining the source code. And, since it is entirely public domain and the PHP source code is available on demand and it is a single PHP script, it can also be modified in any way you wish, depending on your PHP programming skills. Most of the source code is well-documented to explain its inner workings to anyone wishing to modify it. ##############################################################################

PHP Program by Jay Tanner v1.0 - Revised: 1970-Jan-01-Thu at Local Time 12:00:00 AM (UTC−05:00)