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 03:03:41 2024 Pasadena, USA / Horizons ******************************************************************************* Target body name: TESS (spacecraft) (-95) {source: TESS_merged} Center body name: Earth (399) {source: TESS_merged} Center-site name: iTelescope Obs., Siding Spring ******************************************************************************* 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 : 149.0644, -31.2733577, 1.16499 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 149.0644,5457.31536,-3292.4397 {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 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Nov-30 09:00 C 02 21 36.50 -27 31 51.0 94.873487 53.495602 n.a. n.a. 0.987325909851 0.2879139 0.00207573509652 -0.4877718 122.3066 /T 57.5914 126.2/ 1.0117 n.a. n.a. 24.402420 28.809937 -38.54129 2024-Nov-30 09:10 C 02 21 45.15 -27 28 15.6 93.713782 55.584600 n.a. n.a. 0.987327062431 0.2868297 0.00207379866948 -0.4777164 122.3693 /T 57.5289 126.2/ 0.9958 n.a. n.a. 24.449422 27.591656 -37.93354 2024-Nov-30 09:20 C 02 21 53.48 -27 24 37.2 92.498316 57.677503 n.a. n.a. 0.987328210655 0.2857414 0.00207190344502 -0.4672303 122.4320 /T 57.4663 126.2/ 0.9799 n.a. n.a. 24.524140 26.415652 -37.25968 2024-Nov-30 09:30 N 02 22 01.49 -27 20 55.9 91.213178 59.773342 n.a. n.a. 0.987329354505 0.2846489 0.00207005110966 -0.4563340 122.4948 /T 57.4038 126.2/ 0.9640 n.a. n.a. 24.625431 25.287364 -36.52185 2024-Nov-30 09:40 N 02 22 09.22 -27 17 11.6 89.840490 61.870978 n.a. n.a. 0.987330493965 0.2835523 0.00206824326695 -0.4450485 122.5576 /T 57.3411 126.3/ 0.9480 n.a. n.a. 24.752038 24.211665 -35.72261 2024-Nov-30 09:50 N 02 22 16.68 -27 13 24.1 88.356824 63.969032 n.a. n.a. 0.987331629018 0.2824514 0.00206648143390 -0.4333959 122.6206 /T 57.2783 126.3/ 0.9319 n.a. n.a. 24.902603 23.192818 -34.86498 2024-Nov-30 10:00 A 02 22 23.88 -27 09 33.5 86.730813 66.065772 n.a. n.a. 0.987332759648 0.2813463 0.00206476703776 -0.4213989 122.6838 /T 57.2153 126.3/ 0.9159 n.a. n.a. 25.075703 22.234460 -33.95233 2024-Nov-30 10:10 A 02 22 30.85 -27 05 39.6 84.919453 68.158944 n.a. n.a. 0.987333885837 0.2802371 0.00206310141282 -0.4090811 122.7472 /T 57.1520 126.3/ 0.8998 n.a. n.a. 25.269863 21.339592 -32.98840 2024-Nov-30 10:20 A 02 22 37.61 -27 01 42.4 82.862170 70.245488 n.a. n.a. 0.987335007568 0.2791236 0.00206148579755 -0.3964667 122.8109 /T 57.0884 126.3/ 0.8837 n.a. n.a. 25.483587 20.510594 -31.97722 2024-Nov-30 10:30 02 22 44.17 -26 57 41.9 80.471004 72.321072 n.a. n.a. 0.987336124825 0.2780058 0.00205992133176 -0.3835806 122.8750 /T 57.0245 126.3/ 0.8677 n.a. n.a. 25.715375 19.749252 -30.92311 2024-Nov-30 10:40 02 22 50.56 -26 53 38.1 77.613709 74.379260 n.a. n.a. 0.987337237590 0.2768838 0.00205840905413 -0.3704484 122.9395 /T 56.9602 126.4/ 0.8516 n.a. n.a. 25.963743 19.056786 -29.83056 2024-Nov-30 10:50 02 22 56.80 -26 49 30.9 74.083455 76.409978 n.a. n.a. 0.987338345846 0.2757575 0.00205694989975 -0.3570961 123.0044 /T 56.8954 126.4/ 0.8356 n.a. n.a. 26.227243 18.433902 -28.70428 2024-Nov-30 11:00 02 23 02.90 -26 45 20.2 69.542443 78.396490 n.a. n.a. 0.987339449577 0.2746269 0.00205554469807 -0.3435504 123.0698 /T 56.8301 126.4/ 0.8196 n.a. n.a. 26.504473 17.880830 -27.54906 2024-Nov-30 11:10 02 23 08.90 -26 41 06.1 63.414603 80.309090 n.a. n.a. 0.987340548764 0.2734920 0.00205419417089 -0.3298383 123.1358 /T 56.7642 126.4/ 0.8037 n.a. n.a. 26.794091 17.397379 -26.36979 2024-Nov-30 11:20 02 23 14.81 -26 36 48.6 54.689854 82.091254 n.a. n.a. 0.987341643391 0.2723528 0.00205289893078 -0.3159872 123.2024 /T 56.6978 126.4/ 0.7879 n.a. n.a. 27.094826 16.982984 -25.17136 2024-Nov-30 11:30 02 23 20.65 -26 32 27.6 41.670537 83.629567 n.a. n.a. 0.987342733440 0.2712093 0.00205165947941 -0.3020249 123.2697 /T 56.6307 126.5/ 0.7721 n.a. n.a. 27.405486 16.636756 -23.95867 2024-Nov-30 11:40 02 23 26.45 -26 28 03.2 22.326947 84.703929 n.a. n.a. 0.987343818894 0.2700615 0.00205047620657 -0.2879796 123.3376 /T 56.5629 126.5/ 0.7565 n.a. n.a. 27.724960 16.357524 -22.73656 2024-Nov-30 11:50 t 02 23 32.23 -26 23 35.3 357.528994 85.002690 n.a. n.a. 0.987344899736 0.2689092 0.00204934938895 -0.2738794 123.4063 /T 56.4943 126.5/ 0.7409 n.a. n.a. 28.052227 16.143882 -21.50977 2024-Nov-30 12:00 02 23 38.01 -26 19 04.0 334.111659 84.398349 n.a. n.a. 0.987345975947 0.2677526 0.00204827918953 -0.2597528 123.4757 /T 56.4250 126.5/ 0.7255 n.a. n.a. 28.386353 15.994222 -20.28292 2024-Nov-30 12:10 02 23 43.81 -26 14 29.4 317.130316 83.123862 n.a. n.a. 0.987347047511 0.2665917 0.00204726565697 -0.2456283 123.5460 /T 56.3549 126.5/ 0.7101 n.a. n.a. 28.726495 15.906774 -19.06047 2024-Nov-30 12:20 02 23 49.65 -26 09 51.3 305.844310 81.473976 n.a. n.a. 0.987348114409 0.2654263 0.00204630872547 -0.2315345 123.6171 /T 56.2839 126.5/ 0.6950 n.a. n.a. 29.071897 15.879630 -17.84669 2024-Nov-30 12:30 02 23 55.57 -26 05 09.9 298.179027 79.625973 n.a. n.a. 0.987349176625 0.2642565 0.00204540821466 -0.2175000 123.6892 /T 56.2120 126.6/ 0.6799 n.a. n.a. 29.421892 15.910777 -16.64566 2024-Nov-30 12:40 02 24 01.57 -26 00 25.2 292.696024 77.668545 n.a. n.a. 0.987350234140 0.2630823 0.00204456382986 -0.2035531 123.7621 /T 56.1391 126.6/ 0.6651 n.a. n.a. 29.775896 15.998114 -15.46122 2024-Nov-30 12:50 02 24 07.69 -25 55 37.2 288.564652 75.646519 n.a. n.a. 0.987351286936 0.2619036 0.00204377516261 -0.1897222 123.8361 /T 56.0653 126.6/ 0.6504 n.a. n.a. 30.133405 16.139476 -14.29696 2024-Nov-30 13:00 02 24 13.93 -25 50 46.0 285.308366 73.584016 n.a. n.a. 0.987352334996 0.2607205 0.00204304169137 -0.1760353 123.9111 /T 55.9904 126.6/ 0.6358 n.a. n.a. 30.493991 16.332644 -13.15624 2024-Nov-30 13:10 02 24 20.33 -25 45 51.7 282.643672 71.494943 n.a. n.a. 0.987353378302 0.2595329 0.00204236278246 -0.1625204 123.9871 /T 55.9145 126.6/ 0.6215 n.a. n.a. 30.857294 16.575366 -12.04215 2024-Nov-30 13:20 02 24 26.91 -25 40 54.3 280.394311 69.387844 n.a. n.a. 0.987354416836 0.2583408 0.00204173769138 -0.1492047 124.0642 /T 55.8376 126.6/ 0.6073 n.a. n.a. 31.223023 16.865363 -10.95752 2024-Nov-30 13:30 02 24 33.68 -25 35 53.8 278.445975 67.268269 n.a. n.a. 0.987355450579 0.2571443 0.00204116556420 -0.1361154 124.1424 /T 55.7595 126.7/ 0.5934 n.a. n.a. 31.590943 17.200340 -9.904901 2024-Nov-30 13:40 02 24 40.66 -25 30 50.5 276.721678 65.140009 n.a. n.a. 0.987356479515 0.2559432 0.00204064543927 -0.1232792 124.2217 /T 55.6803 126.7/ 0.5796 n.a. n.a. 31.960873 17.577996 -8.886610 2024-Nov-30 13:50 02 24 47.87 -25 25 44.2 275.167818 63.005771 n.a. n.a. 0.987357503623 0.2547375 0.00204017624913 -0.1107221 124.3022 /T 55.5999 126.7/ 0.5661 n.a. n.a. 32.332680 17.996027 -7.904691 2024-Nov-30 14:00 02 24 55.34 -25 20 35.2 273.745971 60.867568 n.a. n.a. 0.987358522888 0.2535274 0.00203975682271 -0.0984697 124.3838 /T 55.5184 126.7/ 0.5528 n.a. n.a. 32.706268 18.452133 -6.960940 2024-Nov-30 14:10 02 25 03.08 -25 15 23.4 272.427874 58.726955 n.a. n.a. 0.987359537289 0.2523126 0.00203938588767 -0.0865469 124.4667 /T 55.4356 126.7/ 0.5398 n.a. n.a. 33.081577 18.944027 -6.056913 2024-Nov-30 14:20 02 25 11.11 -25 10 09.1 271.192257 56.585175 n.a. n.a. 0.987360546809 0.2510933 0.00203906207291 -0.0749780 124.5508 /T 55.3516 126.8/ 0.5269 n.a. n.a. 33.458574 19.469432 -5.193937 2024-Nov-30 14:30 02 25 19.45 -25 04 52.2 270.022779 54.443255 n.a. n.a. 0.987361551429 0.2498694 0.00203878391150 -0.0637866 124.6361 /T 55.2664 126.8/ 0.5144 n.a. n.a. 33.837247 20.026091 -4.373116 2024-Nov-30 14:40 02 25 28.11 -24 59 32.9 268.906646 52.302067 n.a. n.a. 0.987362551132 0.2486409 0.00203854984351 -0.0529954 124.7227 /T 55.1800 126.8/ 0.5020 n.a. n.a. 34.217598 20.611769 -3.595347 2024-Nov-30 14:50 02 25 37.10 -24 54 11.3 267.833666 50.162377 n.a. n.a. 0.987363545897 0.2474077 0.00203835821928 -0.0426264 124.8105 /T 55.0922 126.8/ 0.4900 n.a. n.a. 34.599639 21.224257 -2.861330 2024-Nov-30 15:00 02 25 46.45 -24 48 47.5 266.795586 48.024868 n.a. n.a. 0.987364535708 0.2461699 0.00203820730268 -0.0327008 124.8997 /T 55.0032 126.8/ 0.4781 n.a. n.a. 34.983384 21.861373 -2.171583 2024-Nov-30 15:10 02 25 56.17 -24 43 21.6 265.785621 45.890170 n.a. n.a. 0.987365520545 0.2449275 0.00203809527469 -0.0232387 124.9901 /T 54.9129 126.9/ 0.4666 n.a. n.a. 35.368843 22.520969 -1.526452 2024-Nov-30 15:20 02 26 06.27 -24 37 53.7 264.798108 43.758868 n.a. n.a. 0.987366500389 0.2436804 0.00203802023700 -0.0142594 125.0818 /T 54.8214 126.9/ 0.4553 n.a. n.a. 35.756022 23.200934 -0.926123 2024-Nov-30 15:30 02 26 16.76 -24 32 24.0 263.828252 41.631523 n.a. n.a. 0.987367475222 0.2424286 0.00203798021590 -0.0057813 125.1748 /T 54.7285 126.9/ 0.4443 n.a. n.a. 36.144911 23.899195 -0.370638 2024-Nov-30 15:40 02 26 27.66 -24 26 52.4 262.871935 39.508673 n.a. n.a. 0.987368445025 0.2411721 0.00203797316615 0.0021783 125.2691 /T 54.6343 126.9/ 0.4336 n.a. n.a. 36.535485 24.613724 0.1400973 2024-Nov-30 15:50 02 26 38.98 -24 21 19.2 261.925574 37.390849 n.a. n.a. 0.987369409778 0.2399109 0.00203799697515 0.0096032 125.3646 /T 54.5388 127.0/ 0.4231 n.a. n.a. 36.927699 25.342538 0.6062982 2024-Nov-30 16:00 02 26 50.73 -24 15 44.5 260.986006 35.278574 n.a. n.a. 0.987370369464 0.2386449 0.00203804946707 0.0164780 125.4615 /T 54.4420 127.0/ 0.4129 n.a. n.a. 37.321481 26.083705 1.0282928 2024-Nov-30 16:10 02 27 02.91 -24 10 08.4 260.050400 33.172373 n.a. n.a. 0.987371324063 0.2373742 0.00203812840721 0.0227888 125.5597 /T 54.3440 127.0/ 0.4030 n.a. n.a. 37.716735 26.835347 1.4065100 2024-Nov-30 16:20 02 27 15.54 -24 04 30.9 259.116192 31.072774 n.a. n.a. 0.987372273556 0.2360987 0.00203823150633 0.0285224 125.6592 /T 54.2446 127.1/ 0.3934 n.a. n.a. 38.113333 27.595643 1.7414695 2024-Nov-30 16:30 02 27 28.62 -23 58 52.3 258.181024 28.980317 n.a. n.a. 0.987373217923 0.2348184 0.00203835642522 0.0336669 125.7599 /T 54.1440 127.1/ 0.3840 n.a. n.a. 38.511116 28.362831 2.0337722 2024-Nov-30 16:40 02 27 42.16 -23 53 12.6 257.242705 26.895553 n.a. n.a. 0.987374157146 0.2335334 0.00203850077918 0.0382116 125.8619 /T 54.0421 127.1/ 0.3750 n.a. n.a. 38.909890 29.135209 2.2840916 2024-Nov-30 16:50 02 27 56.17 -23 47 32.0 256.299169 24.819049 n.a. n.a. 0.987375091205 0.2322435 0.00203866214267 0.0421469 125.9652 /T 53.9390 127.2/ 0.3662 n.a. n.a. 39.309430 29.911145 2.4931644 2024-Nov-30 17:00 02 28 10.65 -23 41 50.6 255.348448 22.751392 n.a. n.a. 0.987376020082 0.2309488 0.00203883805401 0.0454643 126.0697 /T 53.8346 127.2/ 0.3577 n.a. n.a. 39.709472 30.689068 2.6617832 2024-Nov-30 17:10 02 28 25.61 -23 36 08.5 254.388644 20.693195 n.a. n.a. 0.987376943755 0.2296492 0.00203902602005 0.0481566 126.1754 /T 53.7290 127.2/ 0.3494 n.a. n.a. 40.109718 31.467481 2.7907887 2024-Nov-30 17:20 A 02 28 41.04 -23 30 25.8 253.417909 18.645096 n.a. n.a. 0.987377862207 0.2283447 0.00203922352091 0.0502178 126.2823 /T 53.6222 127.3/ 0.3415 n.a. n.a. 40.509835 32.244952 2.8810625 2024-Nov-30 17:30 A 02 28 56.96 -23 24 42.6 252.434426 16.607763 n.a. n.a. 0.987378775417 0.2270354 0.00203942801477 0.0516429 126.3904 /T 53.5142 127.3/ 0.3338 n.a. n.a. 40.909454 33.020123 2.9335207 2024-Nov-30 17:40 A 02 29 13.36 -23 18 59.1 251.436390 14.581899 n.a. n.a. 0.987379683365 0.2257212 0.00203963694263 0.0524282 126.4997 /T 53.4051 127.3/ 0.3264 n.a. n.a. 41.308173 33.791707 2.9491078 2024-Nov-30 17:50 A 02 29 30.24 -23 13 15.4 250.421999 12.568247 n.a. n.a. 0.987380586033 0.2244020 0.00203984773306 0.0525713 126.6101 /T 53.2948 127.4/ 0.3192 n.a. n.a. 41.705558 34.558486 2.9287910 2024-Nov-30 18:00 N 02 29 47.60 -23 07 31.5 249.389433 10.567591 n.a. n.a. 0.987381483400 0.2230779 0.00204005780700 0.0520708 126.7216 /T 53.1834 127.4/ 0.3123 n.a. n.a. 42.101142 35.319317 2.8735552 2024-Nov-30 18:10 N 02 30 05.45 -23 01 47.6 248.336851 8.580762 n.a. n.a. 0.987382375447 0.2217489 0.00204026458247 0.0509266 126.8342 /T 53.0709 127.5/ 0.3057 n.a. n.a. 42.494430 36.073125 2.7843975 2024-Nov-30 18:20 Nm 02 30 23.78 -22 56 03.8 247.262375 6.608643 n.a. n.a. 0.987383262153 0.2204149 0.00204046547930 0.0491398 126.9479 /T 52.9574 127.5/ 0.2994 n.a. n.a. 42.884899 36.818905 2.6623238 2024-Nov-30 18:30 Cm 02 30 42.58 -22 50 20.3 246.164084 4.652176 n.a. n.a. 0.987384143499 0.2190759 0.00204065792378 0.0467125 127.0625 /T 52.8428 127.6/ 0.2933 n.a. n.a. 43.272003 37.555720 2.5083441 2024-Nov-30 18:40 Cm 02 31 01.86 -22 44 37.0 245.040001 2.712364 n.a. n.a. 0.987385019464 0.2177319 0.00204083935336 0.0436481 127.1782 /T 52.7273 127.6/ 0.2874 n.a. n.a. 43.655170 38.282699 2.3234688 >..... 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/hrzn_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov ***************************************************************************************************************************************************************************************************************************************************