API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: May 14, 2025 SPHEREx Spacecraft / Sun -163182 https://www.jpl.nasa.gov/missions/spherex/ https://d2pn8kiwq2w21t.cloudfront.net/documents/spherex-press-kit.pdf https://www.youtube.com/watch?v=eOfoWtt0TP8 Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer ("SPHEREx") is a NASA/JPL mission launched to Earth orbit March 12 @ 03:10 UTC from Space Launch Complex 4 East (SLC-4E), Vandenberg Space Force Base, via a Falcon 9. There will then be a 30-day checkout phase to prepare for operations. BACKGROUND: During its nominally 25-month mission, it will use a single instrument (spectrophotometer) with a single observing mode and no moving parts to map the entire sky every 6 months (four times during the two year mission), in 102 different color bands, with much greater color resolution than prior all-sky maps. From an Earth-polar 98-minute orbit ~650 km above the terminator line (thereby keeping pointing at least 91 degrees away from the Sun), SPHEREx will collect data on more than 450 million galaxies along with more than 100 million stars in the Milky Way in order to characterize the origin of the universe. PHYSICAL CHARACTERISTICS: Dimensions : 2.6 m tall, 3.2 m wide and deep solar panels: 2.67 x 1.02 m, produce 750 Watts Total mass : 502 kg Detectors passively cooled to -350 deg. F (-210 C) Three cone-shaped photon shields protect from ambient heat SCIENCE INSTRUMENT: Spectrophotometer has three mirrors (effective diameter, 20 cm) 11 x 3.5 degree field of view Six linear variable filters image each section of the sky in 102 wavelengths of near-infrared TRAJECTORY: Concatenated TLEs from Space-Track, with prediction 30 days into the future. Name Start (TDB) Stop (TDB) ------------------------------------------------------ ----------- ----------- SPHEREx (Concatenated TLEs) 2025-Mar-11 latest+ 30d ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Wed May 14 22:48:48 2025 Pasadena, USA / Horizons ******************************************************************************* Target body name: SPHEREx (spacecraft) (-163182) {source: SPHEREx} Center body name: Earth (399) {source: DE441} Center-site name: Swan Reach Imaging, Glenalta ******************************************************************************* Start time : A.D. 2025-Apr-19 00:00:00.0000 UT Stop time : A.D. 2025-May-01 00:00:00.0000 UT Step-size : 10 minutes ******************************************************************************* Target pole/equ : undefined Target radii : undefined Center geodetic : 139.5701, -34.5440227, .056888 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 139.5701,5259.32258,-3596.34777 {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 : Mixed Julian/Gregorian RTS-only print : NO EOP file : eop.250514.p250810 EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-MAY-14. PREDICTS-> 2025-AUG-09 Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s Table cut-offs 1: Elevation ( 0.0deg=YES),Airmass (>38.000=NO), Daylight (YES) Table cut-offs 2: Solar elongation ( 12.0,180.0=YES),Local Hour Angle( 0.0=NO ) Table cut-offs 3: RA/DEC angular rate ( 0.0=NO ) *************************************************************************************************************************************************************************************************************************************************** Date__(UT)__HR:MN R.A._____(ICRF)_____DEC Azi____(a-app)___Elev APmag S-brt r rdot delta deldot S-O-T /r S-T-O T-O-M/MN_Illu% RA_3sigma DEC_3sigma Sky_motion Sky_mot_PA RelVel-ANG *************************************************************************************************************************************************************************************************************************************************** $$SOE >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2025-Apr-19 09:40 r 01 28 31.73 -34 35 21.8 231.116077 5.143495 n.a. n.a. 1.004401108538 0.7957179 0.00001663972814 4.2237130 46.0396 /L 133.9608 82.8/ 66.4233 n.a. n.a. 30763.221 236.70377 34.320982 >..... Elevation Cut-off Requested .....< 2025-Apr-19 19:50 Ar 02 59 43.18 -41 13 30.0 139.145450 3.635227 n.a. n.a. 1.004520336907 0.1888741 0.00001766549352 -5.1707317 54.9564 /T 125.0416 90.6/ 62.6835 n.a. n.a. 25380.302 290.02969 -43.65139 2025-Apr-19 20:00 Ae 22 08 38.37 +44 29 06.9 30.042674 1.081125 n.a. n.a. 1.004520736522 0.0369164 0.00001910902692 5.4942626 57.6648 /L 122.3355 82.8/ 62.6432 n.a. n.a. 22534.048 336.54821 46.546755 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-20 08:20 Cr 08 32 23.21 +54 04 09.8 8.942310 0.481537 n.a. n.a. 1.004664759096 0.9610950 0.00001943361840 -6.8725116 86.4739 /T 93.5237 149.7/ 57.4448 n.a. n.a. 13781.161 200.70881 -64.77749 2025-Apr-20 08:30 Ct 22 55 10.29 -66 43 33.0 198.182735 17.654515 n.a. n.a. 1.004668373117 0.8123728 0.00001097895479 6.5001353 84.6252 /L 95.3755 51.1/ 57.3465 n.a. n.a. 29303.510 304.96484 59.109803 >..... Elevation Cut-off Requested .....< 2025-Apr-20 20:20 Nr 01 34 23.90 -40 45 10.3 125.293393 21.578687 n.a. n.a. 1.004806124906 0.0960944 0.00000983024937 -4.2338957 52.6473 /L 127.3513 68.6/ 52.2920 n.a. n.a. 52523.557 307.53886 -34.14968 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-21 08:50 Nt 06 30 46.10 +40 45 26.9 341.944638 11.636740 n.a. n.a. 1.004950604295 0.9790338 0.00001306384139 -5.9628826 66.1843 /T 113.8138 148.4/ 46.8631 n.a. n.a. 29636.730 207.65369 -51.87313 2025-Apr-21 09:00 Ne 22 50 16.06 -50 30 54.9 203.495196 1.531436 n.a. n.a. 1.004954166464 0.7694319 0.00001907342306 6.4874203 74.3403 /L 105.6599 38.9/ 46.7618 n.a. n.a. 16538.205 290.42761 59.556044 >..... Elevation Cut-off Requested .....< 2025-Apr-21 19:10 r 01 09 00.42 -17 28 29.7 110.069475 1.567170 n.a. n.a. 1.005071399412 0.0508456 0.00001898497787 -1.8487776 31.8485 /L 148.1502 59.0/ 41.9369 n.a. n.a. 31530.950 318.73912 -14.33017 >..... Elevation Cut-off Requested .....< 2025-Apr-21 20:50 Cr 21 25 51.62 -04 22 15.8 35.277993 54.708672 n.a. n.a. 1.005090311777 0.0048186 0.00000536086826 2.7098071 69.5646 /L 110.4357 17.4/ 41.4616 n.a. n.a. 109250.03 338.02776 20.944392 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-22 09:20 Ar 04 24 52.74 +08 35 15.2 292.778753 15.995452 n.a. n.a. 1.005234827767 0.9767054 0.00001142603011 -2.0080940 35.8149 /T 144.1841 106.4/ 36.0881 n.a. n.a. 52668.629 209.75635 -15.42894 >..... Elevation Cut-off Requested .....< 2025-Apr-22 19:40 r 00 09 50.89 +01 39 44.6 81.106988 9.555888 n.a. n.a. 1.005353806621 -0.0428546 0.00001417203205 0.8218464 29.6552 /L 150.3446 38.2/ 31.1539 n.a. n.a. 43643.557 328.93994 6.2735685 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-23 08:10 Cr 08 58 32.12 +07 58 19.0 29.463374 43.050508 n.a. n.a. 1.005497470667 1.0003742 0.00000620400525 -4.8273289 101.5474 /T 78.4513 160.7/ 26.5548 n.a. n.a. 78300.569 183.48755 -39.42272 >..... Elevation Cut-off Requested .....< 2025-Apr-23 09:50 r 03 00 53.35 -16 58 56.1 254.217016 6.887992 n.a. n.a. 1.005516993225 0.9522179 0.00001559109691 1.7694137 32.7463 /T 147.2539 67.9/ 25.6434 n.a. n.a. 38660.970 219.54917 13.654519 >..... Elevation Cut-off Requested .....< 2025-Apr-23 20:10 Ar 22 38 14.35 +31 55 10.5 38.104233 10.783703 n.a. n.a. 1.005633823286 -0.1292854 0.00001350633587 4.7593215 51.0505 /L 128.9501 41.4/ 20.9813 n.a. n.a. 35995.857 332.62854 39.001071 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-24 08:40 Nt 03 26 02.04 -51 28 03.5 228.231724 37.916321 n.a. n.a. 1.005777338426 0.9682350 0.00000680528511 4.2487738 66.5795 /T 113.4211 69.9/ 16.9395 n.a. n.a. 76141.089 230.82171 34.154461 >..... Elevation Cut-off Requested .....< 2025-Apr-24 20:30 Nr 04 18 18.93 -55 07 19.7 151.229256 11.390897 n.a. n.a. 1.005911526119 -0.0012080 0.00001342907740 -6.2489305 73.3895 /T 106.6085 76.7/ 12.1570 n.a. n.a. 26043.393 265.04905 -55.91890 2025-Apr-24 20:40 Ne 20 41 10.72 +52 33 08.3 4.716455 2.555867 n.a. n.a. 1.005911032864 -0.2040905 0.00001804259129 6.6166959 74.8351 /L 105.1652 66.3/ 12.1142 n.a. n.a. 17021.005 334.54543 60.704806 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-25 09:00 Nt 06 46 58.27 +51 13 57.7 344.075015 1.258672 n.a. n.a. 1.006050081852 1.1498961 0.00001891890035 -6.2289020 66.6175 /T 113.3803 96.6/ 8.9886 n.a. n.a. 18900.257 205.08764 -55.24344 2025-Apr-25 09:10 Ae 00 50 06.28 -47 11 20.5 217.538346 8.769404 n.a. n.a. 1.006054298092 0.9122930 0.00001466992230 5.6445089 63.0590 /L 116.9414 49.6/ 8.9309 n.a. n.a. 28037.247 255.79928 48.627881 >..... Elevation Cut-off Requested .....< 2025-Apr-25 19:20 r 02 30 00.26 -31 26 41.7 128.787169 0.408691 n.a. n.a. 1.006167779647 -0.0476090 0.00001985344852 -3.8460270 44.9832 /T 135.0149 46.1/ 5.6667 n.a. n.a. 26634.882 303.78265 -31.03248 >..... Elevation Cut-off Requested .....< 2025-Apr-25 21:00 Cr 23 03 53.31 -72 57 25.5 164.564852 47.243458 n.a. n.a. 1.006185899918 -0.1162653 0.00000589155253 -4.6826441 91.5804 /L 88.4184 78.9/ 5.3198 n.a. n.a. 83830.209 316.29883 -38.10602 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-26 09:30 Ar 05 13 46.81 +28 37 37.7 311.595736 6.458277 n.a. n.a. 1.006323897071 1.1464834 0.00001570303036 -4.0803141 44.0582 /T 135.9401 64.3/ 3.2608 n.a. n.a. 33481.911 205.92889 -32.70024 >..... Elevation Cut-off Requested .....< 2025-Apr-26 19:50 Ar 01 26 44.43 -21 57 28.0 108.181321 12.288245 n.a. n.a. 1.006438912990 -0.1653886 0.00001295897951 -2.3176514 37.6721 /L 142.3266 33.4/ 1.3488 n.a. n.a. 45640.722 318.77059 -17.95894 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-27 08:20 Cr 08 38 14.99 +37 17 49.7 8.198626 17.665900 n.a. n.a. 1.006575342791 1.1690606 0.00001083483536 -6.5247827 85.4926 /T 94.5055 91.2/ 0.5044 n.a. n.a. 29658.237 196.61049 -59.23427 2025-Apr-27 08:30 Ct 21 40 44.66 -54 22 48.7 193.176433 0.991987 n.a. n.a. 1.006579428130 0.8294962 0.00001949271465 6.8486838 89.7726 /L 90.2276 86.4/ 0.4936 n.a. n.a. 13611.708 334.71950 64.906796 >..... Elevation Cut-off Requested .....< 2025-Apr-27 10:00 r 04 07 28.21 +02 23 28.1 275.994563 4.338046 n.a. n.a. 1.006594164314 1.1181332 0.00001705432478 -0.7847042 29.1882 /T 150.8111 36.3/ 0.3952 n.a. n.a. 36218.344 210.59235 -5.995704 >..... Elevation Cut-off Requested .....< 2025-Apr-27 20:20 Nr 23 24 48.43 +09 14 06.5 57.527478 24.862776 n.a. n.a. 1.006706228427 -0.2744096 0.00000892538043 2.6271806 43.2170 /L 136.7833 43.6/ 0.1182 n.a. n.a. 65706.006 330.59647 20.334536 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-28 08:50 Nt 05 29 36.39 -01 31 39.9 297.412869 35.986114 n.a. n.a. 1.006842133281 1.1336449 0.00000702370124 -1.7676852 48.9287 /T 131.0706 46.0/ 0.5745 n.a. n.a. 86642.500 209.27935 -13.50879 >..... Elevation Cut-off Requested .....< 2025-Apr-28 19:10 r 00 29 05.17 +07 04 12.8 80.391190 1.211091 n.a. n.a. 1.006952442011 -0.3246070 0.00001910029254 1.3320411 29.1283 /L 150.8716 43.6/ 1.8148 n.a. n.a. 31996.153 331.41840 10.221705 >..... Elevation Cut-off Requested .....< 2025-Apr-28 20:40 Nr 06 21 51.11 -54 15 37.3 162.450289 2.770078 n.a. n.a. 1.006970557587 -0.0610792 0.00001823775932 -6.7597204 84.9839 /T 95.0138 86.5/ 2.0639 n.a. n.a. 15259.274 225.93369 -63.54160 2025-Apr-28 20:50 Ce 20 44 46.91 +42 06 25.8 1.732309 13.234226 n.a. n.a. 1.006969599957 -0.3696029 0.00001240361866 6.5091226 76.7059 /L 103.2946 81.3/ 2.0913 n.a. n.a. 26030.824 336.36130 59.051834 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-29 09:20 Ar 02 52 57.26 -31 27 42.0 241.662829 14.488056 n.a. n.a. 1.007105088580 1.0719061 0.00001209775322 3.4903119 46.3895 /T 133.6109 58.6/ 3.7828 n.a. n.a. 45562.266 227.53594 27.651694 >..... Elevation Cut-off Requested .....< 2025-Apr-29 19:40 r 23 35 06.49 +30 57 57.2 48.870154 2.498085 n.a. n.a. 1.007212209293 -0.4185758 0.00001811235351 4.1480931 42.7283 /L 137.2720 62.2/ 6.5107 n.a. n.a. 28827.414 335.94943 33.312960 >..... Elevation Cut-off Requested .....< 2025-Apr-29 21:10 Cr 08 10 05.14 -74 11 02.9 176.373314 19.139955 n.a. n.a. 1.007230447002 -0.2015916 0.00001052416818 -6.4069319 102.8453 /T 77.1529 107.4/ 6.9736 n.a. n.a. 32085.660 172.03239 -57.49783 >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Apr-30 08:10 Cr 12 24 33.20 -86 58 13.8 176.749189 35.665262 n.a. n.a. 1.007346245970 1.0781122 0.00000712253641 5.3527500 107.3581 /T 72.6426 119.6/ 9.3878 n.a. n.a. 62608.920 136.33926 44.801949 >..... Elevation Cut-off Requested .....< 2025-Apr-30 09:50 r 01 45 18.00 -36 25 48.8 224.785267 0.757519 n.a. n.a. 1.007364236591 0.9840385 0.00001962430816 4.5774378 52.3141 /L 127.6861 78.8/ 9.7648 n.a. n.a. 24867.310 243.93237 37.813824 >..... Elevation Cut-off Requested .....< 2025-Apr-30 20:00 Ar 03 11 19.57 -40 32 27.6 133.390490 9.139788 n.a. n.a. 1.007469753491 -0.2502260 0.00001444975916 -4.8581621 56.2232 /T 123.7750 76.2/ 13.6036 n.a. n.a. 32819.645 297.96776 -40.27822 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< $$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 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: "n.a." in output means quantity "not available" at the print-time. SOLAR PRESENCE (OBSERVING SITE) Time tag is followed by a blank, then a solar-presence condition code: '*' Daylight (refracted solar upper-limb on or above apparent horizon) 'C' Civil twilight/dawn 'N' Nautical twilight/dawn 'A' Astronomical twilight/dawn ' ' Night OR geocentric ephemeris LUNAR PRESENCE WITH TARGET RISE/TRANSIT/SET EVENT MARKER (OBSERVING SITE) The solar-presence code column is immediately followed by another marker: 'm' Refracted upper-limb of Moon on or above apparent horizon ' ' Refracted upper-limb of Moon below apparent horizon OR geocentric The lunar presence marker (an ongoing state) can be over-ridden by a target event marker if an event has occurred since the last output step: 'r' Rise (target body on or went above cut-off RTS elevation) 'e' Elevation max (target body maximum elevation angle has occurred) 't' Transit (target body at or passed through observer meridian) 's' Set (target body on or went below cut-off RTS elevation) RTS MARKERS (TVH) Rise and set are with respect to the reference ellipsoid true visual horizon defined by the elevation cut-off angle. Horizon dip and yellow-light refraction (Earth only) are considered. Accuracy is < or = to twice the requested search step-size. 'R.A._____(ICRF)_____DEC' = Astrometric right ascension and declination of the target center with respect to the observing site (coordinate origin) in the reference frame of the planetary ephemeris (ICRF). Compensated for down-leg light-time delay aberration. 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} 'Azi____(a-app)___Elev' = Airless apparent azimuth and elevation of target center. Compensated for light-time, the gravitational deflection of light, stellar aberration, precession and nutation. Azimuth is measured clockwise from north: North(0) -> East(90) -> South(180) -> West(270) -> North (360) Elevation angle is with respect to a plane perpendicular to the reference surface local zenith direction. TOPOCENTRIC ONLY. Units: DEGREES '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 'r rdot' = The Sun's apparent range ("r", light-time aberrated) and range-rate ("rdot") relative to the target center, as seen by the observer. A positive "rdot" means the target center was moving away from the Sun, negative means moving toward the Sun. Units: AU and KM/S '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: AU and KM/S '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 'S-T-O' = The Sun-Target-Observer angle; the interior vertex angle at target center formed by a vector from the target to the apparent center of the Sun (at reflection time on the target) and the apparent vector from target to the observer at print-time. Slightly different from true PHASE ANGLE (requestable separately) at the few arcsecond level in that it includes stellar aberration on the down-leg from target to observer. Units: DEGREES 'T-O-M/MN_Illu%' = Target-Observer-Moon LUNAR ELONGATION angle and illuminated percentage. The apparent lunar elongation angle between target body center and Moon center, seen from the observing site, along with fraction of the lunar disk illuminated by the Sun. A negative lunar elongation angle indicates the target center is behind the Moon. Units: DEGREES & PERCENT 'RA_3sigma DEC_3sigma' = Uncertainty in Right-Ascension and Declination. Output values are the formal +/- 3 standard-deviations (sigmas) around nominal position. Units: ARCSECONDS 'Sky_motion Sky_mot_PA RelVel-ANG' = Total apparent angular rate of the target in the plane-of-sky. "Sky_mot_PA" is the position angle of the target's direction of motion in the plane-of-sky, measured counter-clockwise from the apparent of-date north pole direction. "RelVel-ANG" is the flight path angle of the target's relative motion with respect to the observer's line-of-sight, in the range [-90,+90], where positive values indicate motion away from the observer, negative values are toward the observer: -90 = target is moving directly toward the observer 0 = target is moving at right angles to the observer's line-of-sight +90 = target is moving directly away from the observer UNITS: ARCSECONDS/MINUTE, DEGREES, 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 ***************************************************************************************************************************************************************************************************************************************************