API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: Dec 06, 2024 TESS / (Earth) -95 https://tess.gsfc.nasa.gov/index.html http://spaceflight101.com/tess/tess-orbit-design/ BACKGROUND: The NASA Transiting Exoplanet Survey Satellite (TESS) mission is to detect exoplanets transiting nearby bright stars, targets for followup characterization with large ground telescopes such as the Hubble Space Telescope and the future James Webb Space Telescope. Launched : 2018-Apr-18 22:51 UTC Launch vehicle : Falcon 9 Block 4 Launch site : SLC-40, Cape Canaveral Payload mass : 362 kg Ascent duration : 49 minutes, then TESS deployment A SpaceX Falcon 9 launched the 362-kilogram TESS spacecraft into a Suprasynchronous Transfer Orbit of 200 by 270,000 kilometers at an inclination of 28.5 degrees. The operational orbit chosen for TESS is a highly eccentric, 2:1 lunar resonance orbit of 108,400 by 376,300 kilometers at an inclination of 37 degrees, timed so that the spacecraft reaches apogee with the moon at a phasing of 90 degrees. 11 maneuvering engine burns, 3.5 phasing loops, and a lunar flyby will be used during the first 60 days to go from the inital transfer orbit to the operational orbit. TESS is designed to: - Monitor 200,000 nearby stars for planets - Detect and characterize Earth and Super-Earth size planets - Cover 400X larger sky area than Kepler - Span stellar spectral types of F5 to M5 Transiting exoplanets allow determination of the following: - Fundamental properties: mass, radius, orbit - Dynamics: planet-planet interactions, mutual inclinations, moons, tides - Atmospheric composition & structure: transmission spectrum, emission spectrum, MISSION OVERVIEW: All-sky, two year photometric exoplanet discovery mission. TESS will tile the sky with 26 observation sectors: - At least 27 days staring at each 24 deg. x 96 deg. sector - Brightest 100,000 stars at 1-minute cadence - Full frame images with 30-minute cadence - Map Northern hemisphere in first year - Map Southern hemisphere in second year - Sectors overlap at ecliptic poles for sensitivity to smaller and longer period planets in JWST Continuous Viewing Zone (CVZ) TESS observes from unique High Earth Orbit (HEO): - Unobstructed view for continuous observation - Two 13.7 day orbits per observation sector - Stable 2:1 resonance with Moon's orbit (P/2) - Thermally stable, low-radiation SPACECRAFT: Designed for photometric stability. Heritage Orbital LEOStar-2 spacecraft bus: - 3-axis stabilized pointing, with <= 3 arcsecong performance - Two-headed star tracker; 4 wheel zero-momentum system - 400W single-axis articulating solar array - Passive thermal control - Mono-propellant propulsion system - Ka-band 100 Mbps science downlink - Hexagonal 3.9 x 1.2 x 1.5 meter dimensions when fully deployed - Two 1.1 x 0.89 m solar panels SCIENCE INSTRUMENT: Four wide field-of-view CCD cameras. Each of the four cameras has: - 24 deg. x 24 deg. Field-of-View - 100 mm effective pupil diameter - Lens assembly with 7 optical elements - Athermal design - 600nm - 1000nm bandpass - 16.8 Megapixel, low-noise, low-power, MIT Lincoln Lab CCID-80 detector Trajectory: Post-launch trajectory (starts after launch ascent, L+00:49 min.). Concatenated short-term tag-up predictions, each covering ~3-4 days: Last tracking data used is 2024-Dec-01, predicts thereafter. Trajectory name Start (TDB) Stop (TDB) ------------------------------------ ----------------- ----------------- Concatenated trajectory files (615) 2018-Apr-18 23:37 2026-Jun-03 13:00 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Thu Dec 12 02:49:01 2024 Pasadena, USA / Horizons ******************************************************************************* Target body name: TESS (spacecraft) (-95) {source: TESS_merged} Center body name: Earth (399) {source: TESS_merged} Center-site name: El Berrueco ******************************************************************************* Start time : A.D. 2024-Nov-30 00:00:00.0000 UT Stop time : A.D. 2024-Dec-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: DE441} Rel. light bend : Sun {source: TESS_merged} 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.241211.p250309 EOP coverage : DATA-BASED 1962-JAN-20 TO 2024-DEC-11. PREDICTS-> 2025-MAR-08 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-Nov-30 00:00 02 00 25.11 -32 25 02.5 209.790770 9.862770 n.a. n.a. 0.987257643797 0.3406280 0.00215347069047 -0.0549535 115.9106 /T 63.9769 121.6/ 1.6352 n.a. n.a. 30.160268 23.528541 -4.003346 2024-Nov-30 00:10 02 00 34.72 -32 20 24.5 211.707145 8.977880 n.a. n.a. 0.987259008214 0.3397505 0.00215326908669 -0.0456216 115.9876 /T 63.9000 121.6/ 1.6129 n.a. n.a. 30.539297 23.924707 -3.284189 2024-Nov-30 00:20 02 00 44.60 -32 15 43.9 213.593878 8.040400 n.a. n.a. 0.987260369104 0.3388695 0.00215310430136 -0.0365979 116.0659 /T 63.8218 121.7/ 1.5909 n.a. n.a. 30.919087 24.351095 -2.603326 2024-Nov-30 00:30 02 00 54.77 -32 11 00.8 215.450509 7.052244 n.a. n.a. 0.987261726453 0.3379849 0.00215297506069 -0.0279011 116.1452 /T 63.7425 121.7/ 1.5691 n.a. n.a. 31.299399 24.805682 -1.961075 2024-Nov-30 00:40 02 01 05.23 -32 06 15.3 217.276792 6.015338 n.a. n.a. 0.987263080247 0.3370968 0.00215288001715 -0.0195492 116.2258 /T 63.6620 121.7/ 1.5475 n.a. n.a. 31.680013 25.286486 -1.357617 2024-Nov-30 00:50 02 01 16.01 -32 01 27.6 219.072688 4.931611 n.a. n.a. 0.987264430471 0.3362050 0.00215281775207 -0.0115597 116.3076 /T 63.5803 121.7/ 1.5263 n.a. n.a. 32.060719 25.791569 -0.793006 2024-Nov-30 01:00 02 01 27.11 -31 56 37.7 220.838347 3.802987 n.a. n.a. 0.987265777112 0.3353097 0.00215278677844 -0.0039492 116.3906 /T 63.4974 121.7/ 1.5053 n.a. n.a. 32.441315 26.319038 -0.267184 2024-Nov-30 01:10 02 01 38.55 -31 51 45.7 222.574096 2.631371 n.a. n.a. 0.987267120155 0.3344108 0.00215278554369 0.0032664 116.4747 /T 63.4133 121.8/ 1.4846 n.a. n.a. 32.821604 26.867048 0.2200069 2024-Nov-30 01:20 02 01 50.34 -31 46 51.7 224.280427 1.418642 n.a. n.a. 0.987268459586 0.3335083 0.00215281243281 0.0100717 116.5601 /T 63.3281 121.8/ 1.4642 n.a. n.a. 33.201390 27.433805 0.6688152 2024-Nov-30 01:30 02 02 02.49 -31 41 55.9 225.957976 0.166650 n.a. n.a. 0.987269795389 0.3326022 0.00215286577146 0.0164525 116.6467 /T 63.2416 121.8/ 1.4441 n.a. n.a. 33.580475 28.017563 1.0795669 >..... Elevation Cut-off Requested .....< 2024-Nov-30 17:50 N 02 37 33.95 -24 38 10.3 124.001217 0.666678 n.a. n.a. 0.987380586027 0.2244020 0.00204847690404 -0.6034850 126.4483 /T 53.4559 126.5/ 0.5120 n.a. n.a. 28.839619 38.595579 -40.19886 2024-Nov-30 18:00 A 02 37 46.93 -24 34 23.8 125.590627 2.235415 n.a. n.a. 0.987381483396 0.2230779 0.00204606519408 -0.5989843 126.5232 /T 53.3812 126.5/ 0.5035 n.a. n.a. 28.649115 37.558742 -40.20793 2024-Nov-30 18:10 A 02 37 59.51 -24 30 35.5 127.212619 3.776053 n.a. n.a. 0.987382375444 0.2217489 0.00204367258783 -0.5939608 126.5978 /T 53.3068 126.5/ 0.4950 n.a. n.a. 28.481590 36.513483 -40.16878 2024-Nov-30 18:20 A 02 38 11.71 -24 26 45.4 128.869033 5.286737 n.a. n.a. 0.987383262153 0.2204149 0.00204130116325 -0.5884241 126.6720 /T 53.2328 126.6/ 0.4864 n.a. n.a. 28.337479 35.463873 -40.08040 2024-Nov-30 18:30 02 38 23.54 -24 22 53.3 130.561661 6.765520 n.a. n.a. 0.987384143500 0.2190759 0.00203895295812 -0.5823847 126.7459 /T 53.1591 126.6/ 0.4779 n.a. n.a. 28.217084 34.414152 -39.94196 2024-Nov-30 18:40 02 38 35.00 -24 18 59.2 132.292226 8.210363 n.a. n.a. 0.987385019467 0.2177319 0.00203662996598 -0.5758542 126.8196 /T 53.0857 126.6/ 0.4693 n.a. n.a. 28.120572 33.368678 -39.75285 2024-Nov-30 18:50 02 38 46.11 -24 15 03.1 134.062368 9.619136 n.a. n.a. 0.987385890034 0.2163828 0.00203433413212 -0.5688449 126.8930 /T 53.0124 126.7/ 0.4607 n.a. n.a. 28.047972 32.331877 -39.51269 2024-Nov-30 19:00 02 38 56.89 -24 11 04.7 135.873626 10.989617 n.a. n.a. 0.987386755180 0.2150287 0.00203206734970 -0.5613705 126.9663 /T 52.9393 126.7/ 0.4520 n.a. n.a. 27.999174 31.308184 -39.22135 2024-Nov-30 19:10 02 39 07.33 -24 07 04.1 137.727413 12.319494 n.a. n.a. 0.987387614884 0.2136696 0.00202983145586 -0.5534454 127.0395 /T 52.8663 126.7/ 0.4434 n.a. n.a. 27.973939 30.301992 -38.87896 2024-Nov-30 19:20 02 39 17.45 -24 03 01.2 139.624993 13.606369 n.a. n.a. 0.987388469128 0.2123054 0.00202762822805 -0.5450849 127.1125 /T 52.7935 126.8/ 0.4349 n.a. n.a. 27.971898 29.317589 -38.48588 2024-Nov-30 19:30 02 39 27.27 -23 58 55.9 141.567449 14.847765 n.a. n.a. 0.987389317889 0.2109361 0.00202545938027 -0.5363052 127.1856 /T 52.7206 126.8/ 0.4263 n.a. n.a. 27.992563 28.359113 -38.04276 2024-Nov-30 19:40 02 39 36.80 -23 54 48.1 143.555657 16.041132 n.a. n.a. 0.987390161148 0.2095616 0.00202332655957 -0.5271235 127.2586 /T 52.6478 126.8/ 0.4178 n.a. n.a. 28.035338 27.430503 -37.55051 2024-Nov-30 19:50 02 39 46.05 -23 50 37.8 145.590249 17.183859 n.a. n.a. 0.987390998885 0.2081821 0.00202123134257 -0.5175579 127.3317 /T 52.5749 126.9/ 0.4093 n.a. n.a. 28.099526 26.535453 -37.01028 2024-Nov-30 20:00 02 39 55.05 -23 46 24.9 147.671579 18.273287 n.a. n.a. 0.987391831078 0.2067973 0.00201917523220 -0.5076269 127.4048 /T 52.5019 126.9/ 0.4008 n.a. n.a. 28.184346 25.677382 -36.42350 2024-Nov-30 20:10 02 40 03.79 -23 42 09.3 149.799689 19.306722 n.a. n.a. 0.987392657707 0.2054074 0.00201715965441 -0.4973503 127.4781 /T 52.4288 126.9/ 0.3924 n.a. n.a. 28.288942 24.859402 -35.79181 2024-Nov-30 20:20 02 40 12.31 -23 37 51.1 151.974271 20.281456 n.a. n.a. 0.987393478750 0.2040124 0.00201518595523 -0.4867484 127.5516 /T 52.3556 127.0/ 0.3841 n.a. n.a. 28.412399 24.084299 -35.11712 2024-Nov-30 20:30 02 40 20.61 -23 33 30.2 154.194637 21.194789 n.a. n.a. 0.987394294188 0.2026121 0.00201325539781 -0.4758420 127.6252 /T 52.2821 127.0/ 0.3758 n.a. n.a. 28.553756 23.354522 -34.40152 2024-Nov-30 20:40 02 40 28.72 -23 29 06.5 156.459684 22.044052 n.a. n.a. 0.987395104000 0.2012066 0.00201136915966 -0.4646530 127.6991 /T 52.2084 127.0/ 0.3677 n.a. n.a. 28.712021 22.672174 -33.64734 2024-Nov-30 20:50 02 40 36.64 -23 24 39.9 158.767871 22.826633 n.a. n.a. 0.987395908163 0.1997958 0.00200952833017 -0.4532036 127.7734 /T 52.1343 127.0/ 0.3596 n.a. n.a. 28.886184 22.039014 -32.85705 2024-Nov-30 21:00 02 40 44.41 -23 20 10.6 161.117201 23.540013 n.a. n.a. 0.987396706658 0.1983798 0.00200773390809 -0.4415166 127.8479 /T 52.0599 127.1/ 0.3516 n.a. n.a. 29.075225 21.456464 -32.03334 2024-Nov-30 21:10 02 40 52.03 -23 15 38.4 163.505206 24.181790 n.a. n.a. 0.987397499463 0.1969585 0.00200598679941 -0.4296155 127.9229 /T 51.9852 127.1/ 0.3437 n.a. n.a. 29.278134 20.925618 -31.17900 2024-Nov-30 21:20 02 40 59.53 -23 11 03.3 165.928951 24.749713 n.a. n.a. 0.987398286557 0.1955319 0.00200428781524 -0.4175242 127.9982 /T 51.9100 127.1/ 0.3359 n.a. n.a. 29.493915 20.447260 -30.29697 2024-Nov-30 21:30 02 41 06.92 -23 06 25.3 168.385040 25.241721 n.a. n.a. 0.987399067918 0.1940999 0.00200263767003 -0.4052669 128.0741 /T 51.8343 127.1/ 0.3283 n.a. n.a. 29.721599 20.021879 -29.39030 2024-Nov-30 21:40 02 41 14.22 -23 01 44.5 170.869644 25.655968 n.a. n.a. 0.987399843525 0.1926627 0.00200103697995 -0.3928684 128.1504 /T 51.7581 127.2/ 0.3208 n.a. n.a. 29.960251 19.649691 -28.46212 2024-Nov-30 21:50 02 41 21.45 -22 57 00.7 173.378536 25.990857 n.a. n.a. 0.987400613357 0.1912200 0.00199948626136 -0.3803537 128.2273 /T 51.6814 127.2/ 0.3134 n.a. n.a. 30.208976 19.330658 -27.51561 2024-Nov-30 22:00 02 41 28.64 -22 52 14.0 175.907140 26.245070 n.a. n.a. 0.987401377392 0.1897720 0.00199798592967 -0.3677481 128.3047 /T 51.6041 127.2/ 0.3062 n.a. n.a. 30.466927 19.064509 -26.55404 2024-Nov-30 22:10 02 41 35.79 -22 47 24.4 178.450592 26.417588 n.a. n.a. 0.987402135609 0.1883186 0.00199653629832 -0.3550771 128.3828 /T 51.5262 127.2/ 0.2991 n.a. n.a. 30.733309 18.850764 -25.58064 2024-Nov-30 22:20 t 02 41 42.93 -22 42 32.0 181.003815 26.507712 n.a. n.a. 0.987402887985 0.1868598 0.00199513757793 -0.3423665 128.4616 /T 51.4476 127.3/ 0.2922 n.a. n.a. 31.007384 18.688754 -24.59871 2024-Nov-30 22:30 e 02 41 50.09 -22 37 36.7 183.561597 26.515077 n.a. n.a. 0.987403634500 0.1853955 0.00199378987576 -0.3296421 128.5410 /T 51.3684 127.3/ 0.2854 n.a. n.a. 31.288469 18.577640 -23.61148 2024-Nov-30 22:40 02 41 57.27 -22 32 38.5 186.118679 26.439660 n.a. n.a. 0.987404375131 0.1839258 0.00199249319535 -0.3169297 128.6211 /T 51.2884 127.3/ 0.2788 n.a. n.a. 31.575941 18.516430 -22.62219 2024-Nov-30 22:50 02 42 04.50 -22 27 37.5 188.669839 26.281780 n.a. n.a. 0.987405109856 0.1824506 0.00199124743639 -0.3042553 128.7021 /T 51.2076 127.3/ 0.2724 n.a. n.a. 31.869238 18.504001 -21.63400 2024-Nov-30 23:00 02 42 11.80 -22 22 33.8 191.209983 26.042090 n.a. n.a. 0.987405838653 0.1809698 0.00199005239481 -0.2916447 128.7838 /T 51.1261 127.4/ 0.2662 n.a. n.a. 32.167855 18.539111 -20.65001 2024-Nov-30 23:10 02 42 19.18 -22 17 27.2 193.734222 25.721568 n.a. n.a. 0.987406561500 0.1794836 0.00198890776306 -0.2791236 128.8663 /T 51.0437 127.4/ 0.2602 n.a. n.a. 32.471347 18.620417 -19.67323 2024-Nov-30 23:20 02 42 26.67 -22 12 18.0 196.237951 25.321498 n.a. n.a. 0.987407278375 0.1779918 0.00198781313072 -0.2667176 128.9497 /T 50.9605 127.4/ 0.2543 n.a. n.a. 32.779324 18.746484 -18.70657 2024-Nov-30 23:30 02 42 34.29 -22 07 06.1 198.716908 24.843446 n.a. n.a. 0.987407989256 0.1764945 0.00198676798518 -0.2544520 129.0340 /T 50.8763 127.4/ 0.2487 n.a. n.a. 33.091449 18.915801 -17.75286 2024-Nov-30 23:40 02 42 42.04 -22 01 51.6 201.167230 24.289235 n.a. n.a. 0.987408694120 0.1749916 0.00198577171265 -0.2423520 129.1192 /T 50.7913 127.5/ 0.2433 n.a. n.a. 33.407436 19.126790 -16.81475 2024-Nov-30 23:50 02 42 49.96 -21 56 34.5 203.585491 23.660910 n.a. n.a. 0.987409392945 0.1734830 0.00198482359934 -0.2304424 129.2053 /T 50.7053 127.5/ 0.2380 n.a. n.a. 33.727046 19.377814 -15.89479 2024-Dec-01 00:00 02 42 58.06 -21 51 14.9 205.968726 22.960714 n.a. n.a. 0.987410085709 0.1719689 0.00198392283293 -0.2187474 129.2924 /T 50.6184 127.5/ 0.2330 n.a. n.a. 34.050083 19.667189 -14.99538 $$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/hrzn_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov ***************************************************************************************************************************************************************************************************************************************************