API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: May 07, 2025 Europa Clipper (Spacecraft) / (Sun, Jupiter) -159 https://science.nasa.gov/mission/europa-clipper/ https://europa.nasa.gov/ BACKGROUND: NASA's Europa Clipper spacecraft will carry a suite of science instruments to assess habitability of Jupiter's ice-covered moon Europa (502) while confirming the existence and nature of an expected sub-surface ocean. Launched : 2024-Oct-14 16:06 UTC (SpaceX Falcon Heavy, KSC LC-39A) Mars gravity assist : 2025-Mar-01 Earth gravity assist: 2026-Dec-03 Arrival : 2030-Apr-11 (5.50 year time-of-flight) Mission length : 4.12 years (prime mission, JOI to E49) End-of-mission : 2034-Sep (directed to Ganymede impact ~30d after E49) The spacecraft is expected to orbit Jupiter 75 times and conduct 49 flybys of Europa at altitudes as low as 25 km. This will reduce exposure to the high levels of radiation Europa moves within. Gravity-assists from Europa (49), Ganymede (7), and Callisto (9) will be used to target different Europa close approach points on each flyby. SPACECRAFT: Considering solar arrays and radar antennas, Europa Clipper will be the largest spacecraft NASA has developed to-date for an interplanetary mission. When arrays are deployed, the spacecraft will span 30.5 meters. Main body (bus): 3 x 4.7 x 4 meters Dry mass (no propellant): 3241 kg Propellant: 2750 kg Solar power arrays: 2 x 14.2 x 4.1 meters SCIENCE INSTRUMENTS Europa Imaging System (EIS) Europa Thermal Emission Imaging System (E-THEMIS) Europa Ultraviolet Spectrograph (Europa-UVS) Mapping Imaging Spectrometer for Europa (MISE) Europa Clipper Magnetometer (ECM) Plasma Instrument for Magnetic Sounding (PIMS) Gravity/Radio Science Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) MAss Spectrometer for Planetary EXploration/Europa (MASPEX) SUrface Dust Analyzer (SUDA) SPACECRAFT TRAJECTORY (from JPL navigation): Segments marked by '*' below are pre-launch predictions. Based on tracking data through 2025-Apr-15. Data thereafter is predicted: Trajectory files (JPL mission design/nav) Start End ---------------------------------------------------- ----------- ----------- *21F31_MEGA_L241014_A300411_LP05_V7 (16:13 - 17:08) 2024-Oct-14 2024-Oct-14 trj_241014-241103-dco2410142047-postLaunch-OD001-v1 2024-Oct-14 2024-Oct-18 trj_241018-250130-dco2411082133-cru002-fin-OD018-v14 2024-Oct-18 2024-Nov-23 trj_241123-250315-dco2412031638-cru003-fin-OD020-v1 2024-Nov-23 2024-Dec-04 trj_241204-250311-dco2501221611-MGATRGa-OD034-v1 2024-Dec-04 2025-Jan-04 trj_250104-250614-dco2502250958-cru005-fin-OD042-v1 2025-Jan-04 2025-Feb-15 trj_250215-250726-dco2504160749-cruise006-final-OD055 2025-Feb-15 2025-Jul-26 *21F31_MEGA_L241014_A300411_LP05_V7 2025-Jul-26 2031-Feb-07 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Tue May 13 10:11:27 2025 Pasadena, USA / Horizons ******************************************************************************* Target body name: Europa Clipper (spacecraft) (-159) {source: Europa_Clipper_merged} Center body name: Earth (399) {source: Europa_Clipper_merged} Center-site name: El Berrueco ******************************************************************************* Start time : A.D. 2024-Oct-31 00:00:00.0000 UT Stop time : A.D. 2024-Nov-01 00:00:00.0000 UT Step-size : 10 minutes ******************************************************************************* Target pole/equ : undefined Target radii : undefined Center geodetic : 356.4134, 40.8833094, 1.06361 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 356.4134,4829.88693,4153.33056 {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: Europa_Clipper_merge Rel. light bend : Sun {source: Europa_Clipper_merge 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.250512.p250808 EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-MAY-12. PREDICTS-> 2025-AUG-07 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 2024-Oct-31 00:00 08 35 57.54 +30 25 21.8 64.389204 17.128423 n.a. n.a. 0.998809714239 2.1016576 0.05952767972537 5.8064586 94.0199 /L 82.5729 78.4/ 2.0496 n.a. n.a. 0.2613361 3.2493113 88.145071 2024-Oct-31 00:10 08 35 57.54 +30 25 24.5 65.770212 18.847650 n.a. n.a. 0.998818146552 2.1032771 0.05955096373109 5.8058017 94.0269 /L 82.5646 78.5/ 2.0248 n.a. n.a. 0.2611887 358.53047 88.145183 2024-Oct-31 00:20 08 35 57.53 +30 25 27.1 67.139202 20.585581 n.a. n.a. 0.998826585360 2.1048966 0.05957424626893 5.8057266 94.0340 /L 82.5562 78.6/ 2.0002 n.a. n.a. 0.2623362 353.83009 88.136287 2024-Oct-31 00:30 08 35 57.50 +30 25 29.7 68.498221 22.341079 n.a. n.a. 0.998835030662 2.1065159 0.05959752967173 5.8062330 94.0412 /L 82.5478 78.7/ 1.9759 n.a. n.a. 0.2647533 349.19400 88.118557 2024-Oct-31 00:40 08 35 57.45 +30 25 32.3 69.849411 24.113046 n.a. n.a. 0.998843482459 2.1081352 0.05962081626934 5.8073196 94.0484 /L 82.5393 78.8/ 1.9518 n.a. n.a. 0.2683873 344.66392 88.092364 2024-Oct-31 00:50 08 35 57.39 +30 25 34.8 71.195030 25.900417 n.a. n.a. 0.998851940751 2.1097545 0.05964410838388 5.8089838 94.0556 /L 82.5307 78.9/ 1.9279 n.a. n.a. 0.2731623 340.27522 88.058248 2024-Oct-31 01:00 08 35 57.31 +30 25 37.4 72.537468 27.702158 n.a. n.a. 0.998860405536 2.1113736 0.05966740832506 5.8112222 94.0630 /L 82.5221 79.0/ 1.9044 n.a. n.a. 0.2789842 336.05553 88.016886 2024-Oct-31 01:10 08 35 57.21 +30 25 39.9 73.879274 29.517258 n.a. n.a. 0.998868876816 2.1129927 0.05969071838633 5.8140300 94.0703 /L 82.5135 79.1/ 1.8811 n.a. n.a. 0.2857456 332.02427 87.969051 2024-Oct-31 01:20 08 35 57.10 +30 25 42.4 75.223186 31.344729 n.a. n.a. 0.998877354588 2.1146117 0.05971404084025 5.8174015 94.0778 /L 82.5048 79.2/ 1.8580 n.a. n.a. 0.2933315 328.19306 87.915574 2024-Oct-31 01:30 08 35 56.97 +30 25 44.9 76.572162 33.183596 n.a. n.a. 0.998885838854 2.1162307 0.05973737793433 5.8213300 94.0853 /L 82.4960 79.3/ 1.8353 n.a. n.a. 0.3016238 324.56659 87.857312 2024-Oct-31 01:40 08 35 56.83 +30 25 47.3 77.929427 35.032892 n.a. n.a. 0.998894329613 2.1178495 0.05976073188627 5.8258075 94.0928 /L 82.4872 79.4/ 1.8128 n.a. n.a. 0.3105047 321.14392 87.795117 2024-Oct-31 01:50 08 35 56.67 +30 25 49.7 79.298524 36.891652 n.a. n.a. 0.998902826863 2.1194683 0.05978410487998 5.8308249 94.1004 /L 82.4783 79.5/ 1.7907 n.a. n.a. 0.3198598 317.91971 87.729821 2024-Oct-31 02:00 08 35 56.49 +30 25 52.1 80.683375 38.758901 n.a. n.a. 0.998911330607 2.1210871 0.05980749906142 5.8363725 94.1080 /L 82.4694 79.6/ 1.7688 n.a. n.a. 0.3295799 314.88554 87.662217 2024-Oct-31 02:10 08 35 56.31 +30 25 54.4 82.088363 40.633651 n.a. n.a. 0.998919840842 2.1227057 0.05983091653463 5.8424390 94.1157 /L 82.4605 79.7/ 1.7473 n.a. n.a. 0.3395623 312.03091 87.593049 2024-Oct-31 02:20 08 35 56.10 +30 25 56.6 83.518424 42.514884 n.a. n.a. 0.998928357568 2.1243243 0.05985435935710 5.8490125 94.1234 /L 82.4515 79.8/ 1.7261 n.a. n.a. 0.3497108 309.34414 87.523013 2024-Oct-31 02:30 08 35 55.89 +30 25 58.8 84.979168 44.401541 n.a. n.a. 0.998936880786 2.1259428 0.05987782953645 5.8560801 94.1312 /L 82.4424 79.9/ 1.7052 n.a. n.a. 0.3599369 306.81303 87.452753 2024-Oct-31 02:40 08 35 55.66 +30 26 00.9 86.477026 46.292503 n.a. n.a. 0.998945410495 2.1275612 0.05990132902629 5.8636278 94.1390 /L 82.4333 80.0/ 1.6846 n.a. n.a. 0.3701586 304.42534 87.382856 2024-Oct-31 02:50 08 35 55.42 +30 26 03.0 88.019435 48.186576 n.a. n.a. 0.998953946694 2.1291796 0.05992485972260 5.8716407 94.1469 /L 82.4242 80.1/ 1.6644 n.a. n.a. 0.3803008 302.16912 87.313862 2024-Oct-31 03:00 08 35 55.16 +30 26 04.9 89.615079 50.082460 n.a. n.a. 0.998962489384 2.1307979 0.05994842345992 5.8801032 94.1547 /L 82.4150 80.2/ 1.6445 n.a. n.a. 0.3902946 300.03292 87.246261 2024-Oct-31 03:10 08 35 54.89 +30 26 06.9 91.274185 51.978719 n.a. n.a. 0.998971038563 2.1324161 0.05997202200828 5.8889987 94.1627 /L 82.4058 80.3/ 1.6249 n.a. n.a. 0.4000771 298.00596 87.180500 2024-Oct-31 03:20 08 35 54.61 +30 26 08.7 93.008914 53.873738 n.a. n.a. 0.998979594233 2.1340342 0.05999565706886 5.8983096 94.1706 /L 82.3966 80.4/ 1.6056 n.a. n.a. 0.4095908 296.07814 87.116980 2024-Oct-31 03:30 08 35 54.32 +30 26 10.4 94.833864 55.765671 n.a. n.a. 0.998988156392 2.1356523 0.06001933027157 5.9080178 94.1786 /L 82.3873 80.5/ 1.5867 n.a. n.a. 0.4187832 294.24007 87.056066 2024-Oct-31 03:40 08 35 54.02 +30 26 12.1 96.766724 57.652363 n.a. n.a. 0.998996725040 2.1372703 0.06004304317161 5.9181042 94.1866 /L 82.3780 80.6/ 1.5682 n.a. n.a. 0.4276064 292.48310 86.998084 2024-Oct-31 03:50 08 35 53.71 +30 26 13.7 98.829150 59.531259 n.a. n.a. 0.999005300176 2.1388882 0.06006679724660 5.9285491 94.1947 /L 82.3686 80.7/ 1.5500 n.a. n.a. 0.4360167 290.79924 86.943328 2024-Oct-31 04:00 08 35 53.39 +30 26 15.2 101.047908 61.399269 n.a. n.a. 0.999013881802 2.1405060 0.06009059389375 5.9393322 94.2027 /L 82.3593 80.8/ 1.5321 n.a. n.a. 0.4439746 289.18112 86.892060 2024-Oct-31 04:10 08 35 53.06 +30 26 16.6 103.456409 63.252583 n.a. n.a. 0.999022469915 2.1421238 0.06011443442686 5.9504323 94.2108 /L 82.3499 80.9/ 1.5146 n.a. n.a. 0.4514440 287.62199 86.844511 2024-Oct-31 04:20 08 35 52.73 +30 26 17.9 106.096759 65.086422 n.a. n.a. 0.999031064516 2.1437415 0.06013832007405 5.9618277 94.2189 /L 82.3405 81.0/ 1.4974 n.a. n.a. 0.4583926 286.11559 86.800886 2024-Oct-31 04:30 08 35 52.38 +30 26 19.1 109.022481 66.894679 n.a. n.a. 0.999039665605 2.1453591 0.06016225197537 5.9734963 94.2271 /L 82.3310 81.0/ 1.4805 n.a. n.a. 0.4647909 284.65616 86.761364 2024-Oct-31 04:40 08 35 52.03 +30 26 20.2 112.302088 68.669406 n.a. n.a. 0.999048273181 2.1469767 0.06018623118087 5.9854153 94.2352 /L 82.3216 81.1/ 1.4640 n.a. n.a. 0.4706128 283.23836 86.726099 2024-Oct-31 04:50 08 35 51.67 +30 26 21.3 116.023614 70.400086 n.a. n.a. 0.999056887245 2.1485942 0.06021025864788 5.9975613 94.2434 /L 82.3121 81.2/ 1.4479 n.a. n.a. 0.4758350 281.85722 86.695223 2024-Oct-31 05:00 08 35 51.31 +30 26 22.2 120.299939 72.072592 n.a. n.a. 0.999065507795 2.1502116 0.06023433523979 6.0099108 94.2515 /L 82.3027 81.3/ 1.4321 n.a. n.a. 0.4804370 280.50810 86.668846 2024-Oct-31 05:10 08 35 50.94 +30 26 23.0 125.273946 73.667729 n.a. n.a. 0.999074134831 2.1518289 0.06025846172414 6.0224395 94.2597 /L 82.2932 81.4/ 1.4166 n.a. n.a. 0.4844008 279.18665 86.647057 2024-Oct-31 05:20 A 08 35 50.57 +30 26 23.7 131.120562 75.159278 n.a. n.a. 0.999082768353 2.1534462 0.06028263877133 6.0351232 94.2679 /L 82.2837 81.5/ 1.4014 n.a. n.a. 0.4877113 277.88876 86.629925 2024-Oct-31 05:30 A 08 35 50.20 +30 26 24.3 138.038528 76.511668 n.a. n.a. 0.999091408361 2.1550634 0.06030686695309 6.0479371 94.2761 /L 82.2742 81.6/ 1.3866 n.a. n.a. 0.4903556 276.61053 86.617502 2024-Oct-31 05:40 Am 08 35 49.82 +30 26 24.8 146.217803 77.677952 n.a. n.a. 0.999100054855 2.1566805 0.06033114674155 6.0608563 94.2842 /L 82.2647 81.6/ 1.3721 n.a. n.a. 0.4923233 275.34820 86.609821 2024-Oct-31 05:50 Nm 08 35 49.44 +30 26 25.2 155.763232 78.599986 n.a. n.a. 0.999108707834 2.1582975 0.06035547850848 6.0738555 94.2924 /L 82.2552 81.7/ 1.3579 n.a. n.a. 0.4936066 274.09818 86.606898 2024-Oct-31 06:00 Nm 08 35 49.06 +30 26 25.5 166.570339 79.214273 n.a. n.a. 0.999117367297 2.1599145 0.06037986252390 6.0869093 94.3006 /L 82.2457 81.8/ 1.3441 n.a. n.a. 0.4941997 272.85695 86.608733 2024-Oct-31 06:10 Nm 08 35 48.67 +30 26 25.7 178.212572 79.466403 n.a. n.a. 0.999126033246 2.1615314 0.06040429895622 6.0999925 94.3087 /L 82.2362 81.9/ 1.3305 n.a. n.a. 0.4940994 271.62107 86.615309 2024-Oct-31 06:20 Ct 08 35 48.29 +30 26 25.7 189.974701 79.330507 n.a. n.a. 0.999134705678 2.1631482 0.06042878787183 6.1130794 94.3169 /L 82.2267 82.0/ 1.3173 n.a. n.a. 0.4933046 270.38713 86.626595 2024-Oct-31 06:30 Cm 08 35 47.91 +30 26 25.7 201.094869 78.820812 n.a. n.a. 0.999143384595 2.1647649 0.06045332923472 6.1261447 94.3250 /L 82.2172 82.0/ 1.3044 n.a. n.a. 0.4918165 269.15173 86.642544 >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2024-Oct-31 22:10 08 35 54.52 +30 25 18.5 48.536447 0.390693 n.a. n.a. 0.999988112139 2.3164012 0.06279114518061 5.8171447 94.9350 /L 81.4794 88.9/ 0.4031 n.a. n.a. 0.3013866 42.851701 87.748040 2024-Oct-31 22:20 08 35 54.67 +30 25 20.7 50.152638 1.828640 n.a. n.a. 0.999997405697 2.3180107 0.06281446023220 5.8105844 94.9415 /L 81.4717 89.0/ 0.3927 n.a. n.a. 0.2930236 39.621912 87.807184 2024-Oct-31 22:30 08 35 54.81 +30 25 23.0 51.739285 3.300556 n.a. n.a. 1.000006705711 2.3196201 0.06283775000752 5.8045410 94.9480 /L 81.4639 89.1/ 0.3824 n.a. n.a. 0.2850912 36.199202 87.863479 2024-Oct-31 22:40 08 35 54.93 +30 25 25.3 53.297731 4.804712 n.a. n.a. 1.000016012180 2.3212294 0.06286101660256 5.7990257 94.9546 /L 81.4560 89.2/ 0.3722 n.a. n.a. 0.2776967 32.579050 87.916097 2024-Oct-31 22:50 08 35 55.04 +30 25 27.7 54.829395 6.339445 n.a. n.a. 1.000025325103 2.3228387 0.06288426215608 5.7940488 94.9613 /L 81.4481 89.3/ 0.3622 n.a. n.a. 0.2709503 28.761259 87.964183 2024-Oct-31 23:00 08 35 55.13 +30 25 30.1 56.335764 7.903152 n.a. n.a. 1.000034644481 2.3244478 0.06290748884561 5.7896193 94.9680 /L 81.4401 89.4/ 0.3523 n.a. n.a. 0.2649627 24.751186 88.006878 2024-Oct-31 23:10 08 35 55.21 +30 25 32.5 57.818387 9.494295 n.a. n.a. 1.000043970312 2.3260569 0.06293069888321 5.7857454 94.9747 /L 81.4321 89.5/ 0.3425 n.a. n.a. 0.2598412 20.560853 88.043345 2024-Oct-31 23:20 08 35 55.27 +30 25 34.9 59.278871 11.111397 n.a. n.a. 1.000053302597 2.3276659 0.06295389451103 5.7824340 94.9816 /L 81.4240 89.6/ 0.3329 n.a. n.a. 0.2556859 16.209777 88.072800 2024-Oct-31 23:30 08 35 55.32 +30 25 37.4 60.718881 12.753041 n.a. n.a. 1.000062641335 2.3292749 0.06297707799729 5.7796911 94.9884 /L 81.4159 89.7/ 0.3234 n.a. n.a. 0.2525848 11.725214 88.094553 2024-Oct-31 23:40 08 35 55.35 +30 25 39.9 62.140139 14.417866 n.a. n.a. 1.000071986525 2.3308837 0.06300025163204 5.7775215 94.9954 /L 81.4077 89.8/ 0.3141 n.a. n.a. 0.2506089 7.1416694 88.108043 2024-Oct-31 23:50 08 35 55.37 +30 25 42.4 63.544426 16.104565 n.a. n.a. 1.000081338169 2.3324925 0.06302341772253 5.7759291 95.0023 /L 81.3995 89.9/ 0.3050 n.a. n.a. 0.2498080 2.4995284 88.112872 2024-Nov-01 00:00 08 35 55.37 +30 25 44.9 64.933585 17.811884 n.a. n.a. 1.000090696264 2.3341012 0.06304657858889 5.7749165 95.0094 /L 81.3912 90.0/ 0.2960 n.a. n.a. 0.2502072 357.84288 88.108833 $$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 ***************************************************************************************************************************************************************************************************************************************************