API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: Dec 09, 2024 James Webb Space Telescope / (E-S L2) -170 https://www.jwst.nasa.gov/index.html https://www.youtube.com/watch?v=bTxLAGchWnA The James Webb Space Telescope ("JWST" or "Webb") is a space-based infrared observatory and NASA's successor to the Hubble Space Telescope. Launched by Ariane 5 booster on 2021-Dec-25 @ 12:20 UTC from the ELA-3 launch complex near Korou, French Guiana. After launch, the telescope will deploy during its 30-day, 1.5 million km journey to halo orbit at the second Earth-Sun Lagrange point (E-S L2). Mission duration is nominally 5-10 years. GOALS - Search for the first galaxies or luminous objects formed after the Big Bang - Determine how galaxies evolved from their formation until now - Observe the formation of stars from the first stages to the formation of planetary systems - Measure the physical and chemical properties of planetary systems, including our own Solar System, investigating the potential for life in those systems. TELESCOPE * total launch mass : ~6200 kg (observatory, fuel, launch adaptor) * primary mirror : 25 m^2 mass : 705 kg material : beryllium coated w/48.25 grams gold (golf-ball size) segment mass : 20.1 kg, 39.48 kg for entire segment assembly No. of segments : 18 * focal length : 131.4 meters * optical resolution: 0.1 arcseconds * wavelength : 0.6 - 28.5 microns * size of sun shield: 21.197 m x 14.162 m * Sun shield layers : 1: Max temp 283K, 231 deg. F. 5: Max temp 221K, -80 F Min temp 36K, -394 F * Operating temp : < 50K (-370 deg. F) INSTRUMENTS - Near Infrared Camera (NIRCam) - Near Infrared Spectrograph (NIRSpec) - Mid Infrared Instrument (MIRI) - Fine Guidance Sensors/Near Infrared Imager & Slitless Spectrograph (FGS/NIRISS) TRAJECTORY MCC1A (65-minute engine burn) began 2021-Dec-26 12:50 UTC, completed 01:55 UTC. MCC1B (09:27 engine burn) began 2021-Dec-28 00:20 UTC, completed 00:29:27 UTC. MCC2 (04:57 engine burn) began 2022-Jan-24 19:00 UTC, completed 19:04:57 UTC. Concatenation of reconstructed trajectory solutions (as-flown) from Goddard Flight Dynamics Facility (FDF), based on tracking data through December 08, with prediction thereafter. Trajectory files Start (TDB) End (TDB) ---------------------------------------- ----------------- ----------------- DEFINITIVE_EPHEMERIS_202135913-2024336 2021-Dec-25 13:01 2024-Dec-09 00:01 28D_BURN_PREDICT_SK_2024344000000_06U 2024-Dec-09 00:01 2025-Jan-06 00:01 5Y_SCHEDULE_2024344000000_06U.V0.1 2025-Jan-06 00:01 2029-Dec-08 23:59 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Thu Dec 12 02:56:56 2024 Pasadena, USA / Horizons ******************************************************************************* Target body name: James Webb Space Telescope (spacecraft) (-170) {source: JWST_merged} Center body name: Earth (399) {source: DE441} 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: 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.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 .....< 2024-Nov-30 09:50 N 05 46 50.88 +13 47 40.9 73.438082 0.552290 n.a. n.a. 0.996684495780 -0.1958610 0.01118217473811 -0.3591229 159.2911 /L 20.4817 148.3/ 0.9319 n.a. n.a. 0.1350215 85.499923 -87.09071 2024-Nov-30 10:00 A 05 46 50.93 +13 47 41.0 72.119214 2.598630 n.a. n.a. 0.996683710288 -0.1958315 0.01118074036634 -0.3560409 159.2972 /L 20.4757 148.4/ 0.9159 n.a. n.a. 0.0092141 56.035374 -89.79960 2024-Nov-30 10:10 A 05 46 50.89 +13 47 41.0 70.774551 4.629981 n.a. n.a. 0.996682924915 -0.1958020 0.01117931980954 -0.3522348 159.3036 /L 20.4694 148.5/ 0.8998 n.a. n.a. 0.1182316 269.21627 -87.40290 2024-Nov-30 10:20 A 05 46 50.77 +13 47 41.0 69.400735 6.644891 n.a. n.a. 0.996682139659 -0.1957725 0.01117791595838 -0.3477115 159.3103 /L 20.4628 148.6/ 0.8837 n.a. n.a. 0.2429337 267.71428 -84.60723 2024-Nov-30 10:30 05 46 50.56 +13 47 40.8 67.994303 8.641801 n.a. n.a. 0.996681354523 -0.1957430 0.01117653167280 -0.3424794 159.3173 /L 20.4559 148.7/ 0.8677 n.a. n.a. 0.3661738 267.01747 -81.78075 2024-Nov-30 10:40 05 46 50.27 +13 47 40.6 66.551677 10.619033 n.a. n.a. 0.996680569504 -0.1957136 0.01117516977639 -0.3365483 159.3246 /L 20.4487 148.8/ 0.8516 n.a. n.a. 0.4877002 266.50968 -78.92443 2024-Nov-30 10:50 05 46 49.89 +13 47 40.2 65.069142 12.574776 n.a. n.a. 0.996679784604 -0.1956841 0.01117383305101 -0.3299292 159.3322 /L 20.4412 148.9/ 0.8356 n.a. n.a. 0.6072853 266.07349 -76.03892 2024-Nov-30 11:00 05 46 49.44 +13 47 39.7 63.542841 14.507068 n.a. n.a. 0.996678999822 -0.1956546 0.01117252423136 -0.3226346 159.3401 /L 20.4334 149.0/ 0.8196 n.a. n.a. 0.7247083 265.67034 -73.12498 2024-Nov-30 11:10 05 46 48.90 +13 47 39.1 61.968764 16.413787 n.a. n.a. 0.996678215158 -0.1956251 0.01117124599967 -0.3146782 159.3482 /L 20.4254 149.2/ 0.8037 n.a. n.a. 0.8397537 265.28366 -70.18353 2024-Nov-30 11:20 05 46 48.29 +13 47 38.3 60.342741 18.292628 n.a. n.a. 0.996677430612 -0.1955956 0.01117000098054 -0.3060750 159.3566 /L 20.4170 149.3/ 0.7879 n.a. n.a. 0.9522108 264.90502 -67.21568 2024-Nov-30 11:30 05 46 47.60 +13 47 37.3 58.660448 20.141089 n.a. n.a. 0.996676646185 -0.1955662 0.01116879173576 -0.2968412 159.3653 /L 20.4085 149.4/ 0.7721 n.a. n.a. 1.0618745 264.52954 -64.22272 2024-Nov-30 11:40 05 46 46.84 +13 47 36.2 56.917413 21.956455 n.a. n.a. 0.996675861876 -0.1955367 0.01116762075937 -0.2869945 159.3742 /L 20.3997 149.5/ 0.7565 n.a. n.a. 1.1685449 264.15415 -61.20615 2024-Nov-30 11:50 05 46 46.01 +13 47 34.9 55.109028 23.735774 n.a. n.a. 0.996675077685 -0.1955072 0.01116649047279 -0.2765534 159.3834 /L 20.3906 149.6/ 0.7409 n.a. n.a. 1.2720286 263.77668 -58.16765 2024-Nov-30 12:00 05 46 45.10 +13 47 33.4 53.230580 25.475843 n.a. n.a. 0.996674293612 -0.1954778 0.01116540322005 -0.2655380 159.3928 /L 20.3814 149.7/ 0.7255 n.a. n.a. 1.3721385 263.39551 -55.10911 2024-Nov-30 12:10 05 46 44.14 +13 47 31.7 51.277288 27.173191 n.a. n.a. 0.996673509657 -0.1954483 0.01116436126325 -0.2539691 159.4024 /L 20.3719 149.8/ 0.7101 n.a. n.a. 1.4686944 263.00934 -52.03258 2024-Nov-30 12:20 05 46 43.10 +13 47 29.7 49.244360 28.824060 n.a. n.a. 0.996672725821 -0.1954189 0.01116336677811 -0.2418688 159.4122 /L 20.3622 149.9/ 0.6950 n.a. n.a. 1.5615237 262.61705 -48.94034 2024-Nov-30 12:30 05 46 42.01 +13 47 27.6 47.127065 30.424394 n.a. n.a. 0.996671942102 -0.1953894 0.01116242184968 -0.2292603 159.4222 /L 20.3523 150.0/ 0.6799 n.a. n.a. 1.6504613 262.21763 -45.83479 2024-Nov-30 12:40 05 46 40.86 +13 47 25.2 44.920832 31.969829 n.a. n.a. 0.996671158502 -0.1953600 0.01116152846828 -0.2161677 159.4324 /L 20.3422 150.1/ 0.6651 n.a. n.a. 1.7353505 261.81013 -42.71850 2024-Nov-30 12:50 05 46 39.65 +13 47 22.5 42.621371 33.455692 n.a. n.a. 0.996670375020 -0.1953306 0.01116068852556 -0.2026161 159.4428 /L 20.3320 150.2/ 0.6504 n.a. n.a. 1.8160433 261.39362 -39.59418 2024-Nov-30 13:00 05 46 38.40 +13 47 19.7 40.224819 34.876999 n.a. n.a. 0.996669591656 -0.1953011 0.01115990381080 -0.1886313 159.4533 /L 20.3216 150.4/ 0.6358 n.a. n.a. 1.8924005 260.96718 -36.46464 2024-Nov-30 13:10 05 46 37.09 +13 47 16.5 37.727924 36.228477 n.a. n.a. 0.996668808410 -0.1952717 0.01115917600735 -0.1742404 159.4640 /L 20.3110 150.5/ 0.6215 n.a. n.a. 1.9642925 260.52986 -33.33277 2024-Nov-30 13:20 05 46 35.74 +13 47 13.1 35.128246 37.504588 n.a. n.a. 0.996668025282 -0.1952423 0.01115850668933 -0.1594708 159.4748 /L 20.3003 150.6/ 0.6073 n.a. n.a. 2.0315993 260.08069 -30.20154 2024-Nov-30 13:30 05 46 34.35 +13 47 09.4 32.424389 38.699571 n.a. n.a. 0.996667242273 -0.1952128 0.01115789731855 -0.1443510 159.4857 /L 20.2895 150.7/ 0.5934 n.a. n.a. 2.0942114 259.61863 -27.07394 2024-Nov-30 13:40 05 46 32.91 +13 47 05.4 29.616251 39.807507 n.a. n.a. 0.996666459381 -0.1951834 0.01115734924154 -0.1289100 159.4968 /L 20.2786 150.8/ 0.5796 n.a. n.a. 2.1520294 259.14259 -23.95297 2024-Nov-30 13:50 05 46 31.45 +13 47 01.2 26.705272 40.822398 n.a. n.a. 0.996665676607 -0.1951540 0.01115686368700 -0.1131776 159.5079 /L 20.2676 150.9/ 0.5661 n.a. n.a. 2.2049652 258.65142 -20.84161 2024-Nov-30 14:00 05 46 29.95 +13 46 56.6 23.694678 41.738268 n.a. n.a. 0.996664893951 -0.1951246 0.01115644176326 -0.0971841 159.5191 /L 20.2566 151.0/ 0.5528 n.a. n.a. 2.2529417 258.14386 -17.74281 2024-Nov-30 14:10 05 46 28.42 +13 46 51.8 20.589689 42.549292 n.a. n.a. 0.996664111414 -0.1950952 0.01115608445614 -0.0809601 159.5303 /L 20.2454 151.1/ 0.5398 n.a. n.a. 2.2958937 257.61857 -14.65943 2024-Nov-30 14:20 05 46 26.87 +13 46 46.7 17.397659 43.249930 n.a. n.a. 0.996663328994 -0.1950658 0.01115579262701 -0.0645371 159.5416 /L 20.2343 151.2/ 0.5269 n.a. n.a. 2.3337676 257.07407 -11.59427 2024-Nov-30 14:30 05 46 25.30 +13 46 41.3 14.128144 43.835087 n.a. n.a. 0.996662546692 -0.1950364 0.01115556701105 -0.0479466 159.5530 /L 20.2230 151.4/ 0.5144 n.a. n.a. 2.3665223 256.50879 -8.550009 2024-Nov-30 14:40 05 46 23.72 +13 46 35.5 10.792846 44.300269 n.a. n.a. 0.996661764509 -0.1950069 0.01115540821576 -0.0312207 159.5643 /L 20.2118 151.5/ 0.5020 n.a. n.a. 2.3941296 255.92098 -5.529203 2024-Nov-30 14:50 05 46 22.12 +13 46 29.5 7.405436 44.641739 n.a. n.a. 0.996660982443 -0.1949775 0.01115531671984 -0.0143915 159.5757 /L 20.2006 151.6/ 0.4900 n.a. n.a. 2.4165741 255.30873 -2.534291 2024-Nov-30 15:00 05 46 20.51 +13 46 23.2 3.981242 44.856657 n.a. n.a. 0.996660200496 -0.1949481 0.01115529287216 0.0025084 159.5871 /L 20.1893 151.7/ 0.4781 n.a. n.a. 2.4338540 254.66997 0.4324243 2024-Nov-30 15:10 05 46 18.90 +13 46 16.5 0.536815 44.943191 n.a. n.a. 0.996659418666 -0.1949187 0.01115533689107 0.0194464 159.5984 /L 20.1781 151.8/ 0.4666 n.a. n.a. 2.4459812 254.00239 3.3687760 2024-Nov-30 15:20 t 05 46 17.29 +13 46 09.6 357.089397 44.900593 n.a. n.a. 0.996658636954 -0.1948893 0.01115544886403 0.0363899 159.6097 /L 20.1669 151.9/ 0.4553 n.a. n.a. 2.4529823 253.30344 6.2727293 2024-Nov-30 15:30 05 46 15.68 +13 46 02.3 353.656333 44.729233 n.a. n.a. 0.996657855360 -0.1948599 0.01115562874737 0.0533061 159.6209 /L 20.1558 152.0/ 0.4443 n.a. n.a. 2.4548984 252.57033 9.1423741 2024-Nov-30 15:40 05 46 14.08 +13 45 54.7 350.254473 44.430581 n.a. n.a. 0.996657073885 -0.1948305 0.01115587636639 0.0701625 159.6321 /L 20.1447 152.1/ 0.4336 n.a. n.a. 2.4517863 251.79991 11.975913 2024-Nov-30 15:50 05 46 12.48 +13 45 46.9 346.899613 44.007145 n.a. n.a. 0.996656292527 -0.1948012 0.01115619141573 0.0869265 159.6432 /L 20.1338 152.2/ 0.4231 n.a. n.a. 2.4437187 250.98873 14.771647 2024-Nov-30 16:00 05 46 10.91 +13 45 38.7 343.606030 43.462372 n.a. n.a. 0.996655511287 -0.1947718 0.01115657345993 0.1035657 159.6542 /L 20.1229 152.3/ 0.4129 n.a. n.a. 2.4307848 250.13293 17.527955 2024-Nov-30 16:10 05 46 09.35 +13 45 30.2 340.386123 42.800515 n.a. n.a. 0.996654730165 -0.1947424 0.01115702193434 0.1200482 159.6651 /L 20.1121 152.4/ 0.4030 n.a. n.a. 2.4130917 249.22818 20.243267 2024-Nov-30 16:20 05 46 07.82 +13 45 21.5 337.250187 42.026484 n.a. n.a. 0.996653949160 -0.1947130 0.01115753614621 0.1363421 159.6758 /L 20.1014 152.5/ 0.3934 n.a. n.a. 2.3907650 248.26965 22.916044 2024-Nov-30 16:30 05 46 06.31 +13 45 12.4 334.206324 41.145686 n.a. n.a. 0.996653168274 -0.1946836 0.01115811527605 0.1524159 159.6865 /L 20.0909 152.6/ 0.3840 n.a. n.a. 2.3639498 247.25193 25.544736 2024-Nov-30 16:40 05 46 04.83 +13 45 03.1 331.260465 40.163866 n.a. n.a. 0.996652387505 -0.1946543 0.01115875837927 0.1682388 159.6970 /L 20.0805 152.7/ 0.3750 n.a. n.a. 2.3328122 246.16894 28.127751 2024-Nov-30 16:50 05 46 03.38 +13 44 53.5 328.416494 39.086964 n.a. n.a. 0.996651606855 -0.1946249 0.01115946438807 0.1837803 159.7073 /L 20.0703 152.8/ 0.3662 n.a. n.a. 2.2975410 245.01383 30.663414 2024-Nov-30 17:00 05 46 01.97 +13 44 43.6 325.676429 37.920983 n.a. n.a. 0.996650826322 -0.1945956 0.01116023211351 0.1990104 159.7174 /L 20.0603 152.9/ 0.3577 n.a. n.a. 2.2583494 243.77892 33.149915 2024-Nov-30 17:10 05 46 00.61 +13 44 33.4 323.040665 36.671880 n.a. n.a. 0.996650045907 -0.1945662 0.01116106024787 0.2138998 159.7274 /L 20.0504 153.0/ 0.3494 n.a. n.a. 2.2154775 242.45553 35.585258 2024-Nov-30 17:20 A 05 45 59.28 +13 44 23.0 320.508214 35.345479 n.a. n.a. 0.996649265609 -0.1945368 0.01116194736725 0.2284200 159.7371 /L 20.0407 153.1/ 0.3415 n.a. n.a. 2.1691947 241.03389 37.967199 2024-Nov-30 17:30 A 05 45 58.00 +13 44 12.3 318.076964 33.947399 n.a. n.a. 0.996648485430 -0.1945075 0.01116289193438 0.2425430 159.7467 /L 20.0313 153.1/ 0.3338 n.a. n.a. 2.1198033 239.50300 40.293177 2024-Nov-30 17:40 A 05 45 56.78 +13 44 01.4 315.743910 32.483010 n.a. n.a. 0.996647705368 -0.1944782 0.01116389230163 0.2562416 159.7560 /L 20.0220 153.2/ 0.3264 n.a. n.a. 2.0676419 237.85050 42.560231 2024-Nov-30 17:50 A 05 45 55.61 +13 43 50.2 313.505374 30.957395 n.a. n.a. 0.996646925423 -0.1944488 0.01116494671428 0.2694897 159.7651 /L 20.0130 153.3/ 0.3192 n.a. n.a. 2.0130905 236.06255 44.764914 2024-Nov-30 18:00 N 05 45 54.49 +13 43 38.8 311.357191 29.375335 n.a. n.a. 0.996646145597 -0.1944195 0.01116605331397 0.2822618 159.7739 /L 20.0042 153.4/ 0.3123 n.a. n.a. 1.9565751 234.12370 46.903192 2024-Nov-30 18:10 N 05 45 53.44 +13 43 27.2 309.294865 27.741302 n.a. n.a. 0.996645365888 -0.1943902 0.01116721014235 0.2945334 159.7826 /L 19.9957 153.5/ 0.3057 n.a. n.a. 1.8985745 232.01686 48.970323 2024-Nov-30 18:20 Nm 05 45 52.44 +13 43 15.4 307.313705 26.059457 n.a. n.a. 0.996644586297 -0.1943608 0.01116841514495 0.3062812 159.7909 /L 19.9874 153.6/ 0.2994 n.a. n.a. 1.8396263 229.72332 50.960740 2024-Nov-30 18:30 Cm 05 45 51.51 +13 43 03.4 305.408927 24.333657 n.a. n.a. 0.996643806823 -0.1943315 0.01116966617517 0.3174826 159.7990 /L 19.9794 153.6/ 0.2933 n.a. n.a. 1.7803349 227.22291 52.867917 2024-Nov-30 18:40 Cm 05 45 50.65 +13 42 51.1 303.575734 22.567471 n.a. n.a. 0.996643027467 -0.1943022 0.01117096099854 0.3281162 159.8068 /L 19.9717 153.7/ 0.2874 n.a. n.a. 1.7213786 224.49439 54.684238 >..... 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 ***************************************************************************************************************************************************************************************************************************************************