API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: Dec 06, 2024 Gaia Observatory -139479 http://sci.esa.int/gaia/ NOTE: Science observations to end 2025-Jan-25 due to decreasing attitude control propellant. After a few weeks of engineering tests, Gaia will leave its orbit around L2 and be placed in a heliocentric disposal orbit. BACKGROUND: Gaia is designed and operated by the European Space Agency. It launched December 19, 2013 @ 09:12 UTC on a Soyuz launcher from Kourou, French Guiana. On 2014-Jan-08, it arrived at its operational Lissajous orbit around the gravitationally stable Earth-Sun Lagrange-point L2, roughly 1.5 million km from Earth in the direction opposite the Sun. The orbit is not shadowed by Earth eclipses. The orbit period is about 180 days; the size of the orbit is typically 340,000 x 90,000 km. MISSION: Gaia's 5-year primary mission is to ... * Measure the positions of ~1 billion stars both in our Galaxy and other members of the Local Group, with an accuracy down to 24 uas * Perform spectral and photometric measurements of all objects * Derive space velocities of the Galaxy's constituent stars using the stellar distances and motions * Create a three-dimensional structural map of the Galaxy Additional expected results include extrasolar planet detection, brown dwarf detection, solar system asteroid discoveries, supernova early detection, and testing of Einstein's general relativity. GAIA SPACECRAFT: Spacecraft dry mass total 1392 kg Propellant 237 kg Total launch mass 2029 kg Power: 12.8 m^2 solar array provides up to 1910 Watts SCIENCE INSTRUMENTS: Single integrated instrument that comprises three major functions: astrometry, photometry (320-1000 nm) and spectrometry (846-874 nm). The three functions use two common telescopes and a shared focal plane, with each function having a dedicated area on the large 0.5m x 1m CCD detector array. SPACECRAFT TRAJECTORY (from ESA 2024-Dec-03, predicts thereafter) Trajectory name Start Stop -------------------------------------------- ----------- ----------- ORB1_20241203_000001 2013-Dec-19 2026-Sep-14 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Thu Dec 12 04:16:58 2024 Pasadena, USA / Horizons ******************************************************************************* Target body name: Gaia (spacecraft) (-139479) {source: gaia_merged} Center body name: Earth (399) {source: gaia_merged} Center-site name: VdS Remote Observatory, Hakos ******************************************************************************* 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 : 16.3613, -23.2365766, 1.8515 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 16.3613,5865.52307,-2501.54567 {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: gaia_merged} Rel. light bend : Sun {source: gaia_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 03 33 29.60 +20 26 36.9 322.034296 36.268366 n.a. n.a. 0.995685671709 -0.3225316 0.00958978023931 0.1608453 168.0274 /T 11.8581 177.1/ 1.5713 n.a. n.a. 0.5527070 194.77416 68.280692 2024-Nov-30 00:10 03 33 29.53 +20 26 31.4 319.766414 34.816475 n.a. n.a. 0.995684378230 -0.3224746 0.00959045483705 0.1754719 168.0198 /T 11.8656 177.2/ 1.5488 n.a. n.a. 0.5840129 185.13697 68.901338 2024-Nov-30 00:20 03 33 29.53 +20 26 25.3 317.606259 33.296842 n.a. n.a. 0.995683084979 -0.3224176 0.00959118723918 0.1896648 168.0124 /T 11.8728 177.3/ 1.5266 n.a. n.a. 0.6288927 176.15566 68.971881 2024-Nov-30 00:30 03 33 29.59 +20 26 18.8 315.549644 31.714833 n.a. n.a. 0.995681791957 -0.3223606 0.00959197565116 0.2033968 168.0054 /T 11.8798 177.4/ 1.5048 n.a. n.a. 0.6866692 168.04533 68.622816 2024-Nov-30 00:40 03 33 29.73 +20 26 11.9 313.591927 30.075464 n.a. n.a. 0.995680499164 -0.3223036 0.00959281817179 0.2166417 167.9985 /T 11.8866 177.4/ 1.4834 n.a. n.a. 0.7562060 160.87760 67.964137 2024-Nov-30 00:50 03 33 29.95 +20 26 04.5 311.728190 28.383386 n.a. n.a. 0.995679206599 -0.3222466 0.00959371279686 0.2293744 167.9920 /T 11.8930 177.5/ 1.4623 n.a. n.a. 0.8362135 154.61960 67.082813 2024-Nov-30 01:00 03 33 30.25 +20 25 56.8 309.953384 26.642899 n.a. n.a. 0.995677914263 -0.3221896 0.00959465742317 0.2415708 167.9858 /T 11.8992 177.6/ 1.4416 n.a. n.a. 0.9254453 149.18210 66.044277 2024-Nov-30 01:10 03 33 30.63 +20 25 48.7 308.262433 24.857963 n.a. n.a. 0.995676622156 -0.3221326 0.00959564985259 0.2532076 167.9798 /T 11.9051 177.6/ 1.4213 n.a. n.a. 1.0227880 144.45592 64.896139 2024-Nov-30 01:20 03 33 31.10 +20 25 40.2 306.650329 23.032212 n.a. n.a. 0.995675330277 -0.3220755 0.00959668779642 0.2642629 167.9742 /T 11.9106 177.7/ 1.4014 n.a. n.a. 1.1272817 140.33321 63.672343 2024-Nov-30 01:30 03 33 31.65 +20 25 31.4 305.112187 21.168976 n.a. n.a. 0.995674038628 -0.3220185 0.00959776887985 0.2747157 167.9689 /T 11.9158 177.7/ 1.3819 n.a. n.a. 1.2381089 136.71718 62.396830 2024-Nov-30 01:40 03 33 32.31 +20 25 22.2 303.643292 19.271299 n.a. n.a. 0.995672747207 -0.3219614 0.00959889064660 0.2845464 167.9640 /T 11.9207 177.7/ 1.3628 n.a. n.a. 1.3545706 133.52510 61.086410 2024-Nov-30 01:50 03 33 33.06 +20 25 12.7 302.239129 17.341965 n.a. n.a. 0.995671456015 -0.3219044 0.00960005056374 0.2937364 167.9595 /T 11.9252 177.8/ 1.3441 n.a. n.a. 1.4760614 130.68812 59.752868 2024-Nov-30 02:00 03 33 33.90 +20 25 03.0 300.895399 15.383513 n.a. n.a. 0.995670165052 -0.3218473 0.00960124602660 0.3022685 167.9553 /T 11.9293 177.8/ 1.3258 n.a. n.a. 1.6020484 128.14959 58.404476 2024-Nov-30 02:10 03 33 34.85 +20 24 53.0 299.608028 13.398264 n.a. n.a. 0.995668874317 -0.3217903 0.00960247436390 0.3101266 167.9515 /T 11.9330 177.8/ 1.3079 n.a. n.a. 1.7320532 125.86318 57.047044 2024-Nov-30 02:20 03 33 35.90 +20 24 42.8 298.373168 11.388334 n.a. n.a. 0.995667583812 -0.3217332 0.00960373284287 0.3172962 167.9481 /T 11.9364 177.8/ 1.2904 n.a. n.a. 1.8656392 123.79097 55.684650 2024-Nov-30 02:30 03 33 37.06 +20 24 32.3 297.187195 9.355655 n.a. n.a. 0.995666293536 -0.3216761 0.00960501867456 0.3237639 167.9451 /T 11.9393 177.8/ 1.2733 n.a. n.a. 2.0024007 121.90183 54.320158 2024-Nov-30 02:40 A 03 33 38.33 +20 24 21.7 296.046701 7.301993 n.a. n.a. 0.995665003488 -0.3216191 0.00960632901933 0.3295177 167.9425 /T 11.9419 177.8/ 1.2566 n.a. n.a. 2.1419560 120.17013 52.955564 2024-Nov-30 02:50 A 03 33 39.70 +20 24 10.9 294.948484 5.228961 n.a. n.a. 0.995663713670 -0.3215620 0.00960766099216 0.3345471 167.9403 /T 11.9440 177.8/ 1.2404 n.a. n.a. 2.2839410 118.57464 51.592254 2024-Nov-30 03:00 Am 03 33 41.18 +20 23 59.9 293.889539 3.138036 n.a. n.a. 0.995662424081 -0.3215049 0.00960901166842 0.3388427 167.9386 /T 11.9458 177.8/ 1.2245 n.a. n.a. 2.4280055 117.09766 50.231173 2024-Nov-30 03:10 Nm 03 33 42.78 +20 23 48.9 292.867040 1.030567 n.a. n.a. 0.995661134720 -0.3214478 0.00961037808932 0.3423969 167.9372 /T 11.9471 177.8/ 1.2090 n.a. n.a. 2.5738100 115.72435 48.872954 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Nov-30 17:40 C 03 38 40.86 +20 27 17.5 59.874355 14.140804 n.a. n.a. 0.995549839438 -0.3164581 0.00958344767510 -0.4060969 168.4915 /T 11.3983 174.5/ 0.4853 n.a. n.a. 1.8886013 46.858600 -61.68565 2024-Nov-30 17:50 C 03 38 41.79 +20 27 30.3 58.565401 16.114906 n.a. n.a. 0.995548570316 -0.3164005 0.00958183494986 -0.3979744 168.4885 /T 11.4013 174.4/ 0.4752 n.a. n.a. 1.7687343 44.314504 -62.76138 2024-Nov-30 18:00 N 03 38 42.61 +20 27 42.9 57.198576 18.061297 n.a. n.a. 0.995547301426 -0.3163429 0.00958025614681 -0.3891843 168.4852 /T 11.4046 174.4/ 0.4650 n.a. n.a. 1.6534216 41.543943 -63.80247 2024-Nov-30 18:10 N 03 38 43.34 +20 27 55.1 55.769727 19.977576 n.a. n.a. 0.995546032767 -0.3162853 0.00957871391052 -0.3797432 168.4815 /T 11.4083 174.3/ 0.4548 n.a. n.a. 1.5431124 38.520826 -64.80200 2024-Nov-30 18:20 N 03 38 43.98 +20 28 07.0 54.274481 21.861110 n.a. n.a. 0.995544764339 -0.3162277 0.00957721081700 -0.3696689 168.4774 /T 11.4124 174.2/ 0.4446 n.a. n.a. 1.4382729 35.217418 -65.75159 2024-Nov-30 18:30 A 03 38 44.52 +20 28 18.6 52.708254 23.709019 n.a. n.a. 0.995543496142 -0.3161700 0.00957574936846 -0.3589803 168.4729 /T 11.4168 174.1/ 0.4344 n.a. n.a. 1.3393843 31.605274 -66.64114 2024-Nov-30 18:40 A 03 38 44.97 +20 28 29.9 51.066278 25.518149 n.a. n.a. 0.995542228177 -0.3161124 0.00957433198864 -0.3476975 168.4681 /T 11.4216 174.1/ 0.4242 n.a. n.a. 1.2469371 27.656851 -67.45856 2024-Nov-30 18:50 A 03 38 45.34 +20 28 40.8 49.343628 27.285057 n.a. n.a. 0.995540960442 -0.3160548 0.00957296101795 -0.3358420 168.4629 /T 11.4268 174.0/ 0.4141 n.a. n.a. 1.1614200 23.347975 -68.18950 2024-Nov-30 19:00 03 38 45.63 +20 28 51.2 47.535282 29.005988 n.a. n.a. 0.995539692939 -0.3159971 0.00957163870895 -0.3234363 168.4574 /T 11.4323 173.9/ 0.4040 n.a. n.a. 1.0833017 18.661326 -68.81718 2024-Nov-30 19:10 03 38 45.83 +20 29 01.3 45.636184 30.676857 n.a. n.a. 0.995538425667 -0.3159395 0.00957036722190 -0.3105037 168.4515 /T 11.4381 173.8/ 0.3940 n.a. n.a. 1.0130028 13.590876 -69.32232 2024-Nov-30 19:20 03 38 45.97 +20 29 10.9 43.641343 32.293231 n.a. n.a. 0.995537158627 -0.3158818 0.00956914862054 -0.2970690 168.4453 /T 11.4442 173.7/ 0.3840 n.a. n.a. 0.9508575 8.1468657 -69.68331 2024-Nov-30 19:30 03 38 46.02 +20 29 20.1 41.545955 33.850325 n.a. n.a. 0.995535891818 -0.3158241 0.00956798486804 -0.2831577 168.4389 /T 11.4506 173.6/ 0.3741 n.a. n.a. 0.8970657 2.3603431 -69.87657 2024-Nov-30 19:40 03 38 46.02 +20 29 28.8 39.345559 35.342994 n.a. n.a. 0.995534625240 -0.3157665 0.00956687782309 -0.2687963 168.4321 /T 11.4573 173.5/ 0.3643 n.a. n.a. 0.8516414 356.28577 -69.87718 2024-Nov-30 19:50 03 38 45.94 +20 29 37.1 37.036229 36.765745 n.a. n.a. 0.995533358893 -0.3157088 0.00956582923633 -0.2540123 168.4251 /T 11.4643 173.4/ 0.3546 n.a. n.a. 0.8143666 350.00002 -69.65960 2024-Nov-30 20:00 03 38 45.81 +20 29 44.9 34.614798 38.112754 n.a. n.a. 0.995532092778 -0.3156511 0.00956484074679 -0.2388337 168.4178 /T 11.4715 173.3/ 0.3450 n.a. n.a. 0.7847645 343.59676 -69.19820 2024-Nov-30 20:10 03 38 45.63 +20 29 52.1 32.079121 39.377908 n.a. n.a. 0.995530826894 -0.3155934 0.00956391387875 -0.2232896 168.4103 /T 11.4790 173.2/ 0.3355 n.a. n.a. 0.7621018 337.17661 -68.46720 2024-Nov-30 20:20 03 38 45.39 +20 29 58.9 29.428366 40.554858 n.a. n.a. 0.995529561242 -0.3155358 0.00956305003869 -0.2074099 168.4026 /T 11.4866 173.1/ 0.3261 n.a. n.a. 0.7454253 330.83529 -67.43972 2024-Nov-30 20:30 03 38 45.11 +20 30 05.1 26.663321 41.637107 n.a. n.a. 0.995528295821 -0.3154781 0.00956225051249 -0.1912247 168.3947 /T 11.4945 173.0/ 0.3169 n.a. n.a. 0.7336271 324.65271 -66.08567 2024-Nov-30 20:40 03 38 44.79 +20 30 10.9 23.786698 42.618109 n.a. n.a. 0.995527030632 -0.3154203 0.00956151646291 -0.1747652 168.3866 /T 11.5025 172.9/ 0.3078 n.a. n.a. 0.7255235 318.68574 -64.36819 2024-Nov-30 20:50 03 38 44.43 +20 30 16.0 20.803413 43.491408 n.a. n.a. 0.995525765674 -0.3153626 0.00956084892727 -0.1580629 168.3783 /T 11.5107 172.8/ 0.2989 n.a. n.a. 0.7199338 312.96550 -62.23880 2024-Nov-30 21:00 03 38 44.04 +20 30 20.6 17.720809 44.250792 n.a. n.a. 0.995524500947 -0.3153049 0.00956024881539 -0.1411498 168.3699 /T 11.5191 172.7/ 0.2901 n.a. n.a. 0.7157444 307.49868 -59.63072 2024-Nov-30 21:10 03 38 43.62 +20 30 24.7 14.548778 44.890469 n.a. n.a. 0.995523236453 -0.3152472 0.00955971690782 -0.1240583 168.3613 /T 11.5276 172.6/ 0.2815 n.a. n.a. 0.7119544 302.27121 -56.45036 2024-Nov-30 21:20 03 38 43.18 +20 30 28.2 11.299767 45.405256 n.a. n.a. 0.995521972190 -0.3151895 0.00955925385423 -0.1068213 168.3527 /T 11.5361 172.5/ 0.2731 n.a. n.a. 0.7077031 297.25267 -52.56622 2024-Nov-30 21:30 03 38 42.73 +20 30 31.2 7.988621 45.790764 n.a. n.a. 0.995520708158 -0.3151317 0.00955886017218 -0.0894718 168.3439 /T 11.5448 172.4/ 0.2649 n.a. n.a. 0.7022829 292.40030 -47.79580 2024-Nov-30 21:40 03 38 42.26 +20 30 33.5 4.632259 46.043573 n.a. n.a. 0.995519444358 -0.3150740 0.00955853624606 -0.0720432 168.3351 /T 11.5535 172.3/ 0.2568 n.a. n.a. 0.6951440 287.66191 -41.89385 2024-Nov-30 21:50 03 38 41.78 +20 30 35.4 1.249191 46.161375 n.a. n.a. 0.995518180790 -0.3150163 0.00955828232634 -0.0545688 168.3263 /T 11.5623 172.2/ 0.2490 n.a. n.a. 0.6858944 282.97757 -34.55424 2024-Nov-30 22:00 t 03 38 41.31 +20 30 36.6 357.858903 46.143076 n.a. n.a. 0.995516917453 -0.3149585 0.00955809852909 -0.0370823 168.3174 /T 11.5711 172.1/ 0.2414 n.a. n.a. 0.6743018 278.28011 -25.45800 2024-Nov-30 22:10 03 38 40.84 +20 30 37.3 354.481143 45.988847 n.a. n.a. 0.995515654348 -0.3149007 0.00955798483571 -0.0196172 168.3085 /T 11.5800 172.0/ 0.2340 n.a. n.a. 0.6602987 273.49472 -14.42611 2024-Nov-30 22:20 03 38 40.37 +20 30 37.4 351.135202 45.700115 n.a. n.a. 0.995514391475 -0.3148430 0.00955794109300 -0.0022070 168.2996 /T 11.5888 171.8/ 0.2268 n.a. n.a. 0.6439947 268.53781 -1.704658 2024-Nov-30 22:30 03 38 39.92 +20 30 36.9 347.839218 45.279501 n.a. n.a. 0.995513128834 -0.3147852 0.00955796701342 0.0151147 168.2907 /T 11.5976 171.7/ 0.2198 n.a. n.a. 0.6256977 263.31592 11.804061 2024-Nov-30 22:40 03 38 39.49 +20 30 35.9 344.609594 44.730702 n.a. n.a. 0.995511866424 -0.3147274 0.00955806217574 0.0323148 168.2819 /T 11.6063 171.6/ 0.2131 n.a. n.a. 0.6059465 257.72520 24.772473 2024-Nov-30 22:50 03 38 39.08 +20 30 34.3 341.460555 44.058337 n.a. n.a. 0.995510604247 -0.3146697 0.00955822602578 0.0493603 168.2731 /T 11.6150 171.5/ 0.2066 n.a. n.a. 0.5855544 251.65325 36.110731 2024-Nov-30 23:00 03 38 38.70 +20 30 32.2 338.403868 43.267773 n.a. n.a. 0.995509342301 -0.3146119 0.00955845787761 0.0662184 168.2644 /T 11.6236 171.4/ 0.2003 n.a. n.a. 0.5656613 244.98590 45.372264 2024-Nov-30 23:10 03 38 38.35 +20 30 29.5 335.448736 42.364933 n.a. n.a. 0.995508080587 -0.3145541 0.00955875691482 0.0828569 168.2559 /T 11.6320 171.3/ 0.1943 n.a. n.a. 0.5477800 237.62266 52.622331 2024-Nov-30 23:20 03 38 38.04 +20 30 26.3 332.601830 41.356111 n.a. n.a. 0.995506819104 -0.3144963 0.00955912219224 0.0992437 168.2474 /T 11.6404 171.1/ 0.1885 n.a. n.a. 0.5338111 229.50471 58.137018 2024-Nov-30 23:30 03 38 37.78 +20 30 22.6 329.867451 40.247803 n.a. n.a. 0.995505557854 -0.3144385 0.00955955263774 0.1153477 168.2391 /T 11.6486 171.0/ 0.1830 n.a. n.a. 0.5259775 220.65486 62.213336 2024-Nov-30 23:40 03 38 37.56 +20 30 18.3 327.247765 39.046553 n.a. n.a. 0.995504296835 -0.3143807 0.00956004705441 0.1311378 168.2310 /T 11.6567 170.9/ 0.1777 n.a. n.a. 0.5266307 211.21752 65.104494 2024-Nov-30 23:50 03 38 37.39 +20 30 13.5 324.743093 37.758828 n.a. n.a. 0.995503036049 -0.3143229 0.00956060412285 0.1465839 168.2231 /T 11.6645 170.8/ 0.1726 n.a. n.a. 0.5379171 201.47107 67.017934 2024-Dec-01 00:00 03 38 37.28 +20 30 08.3 322.352220 36.390921 n.a. n.a. 0.995501775494 -0.3142651 0.00956122240392 0.1616565 168.2153 /T 11.6722 170.7/ 0.1679 n.a. n.a. 0.5613980 191.78589 68.130835 $$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 ***************************************************************************************************************************************************************************************************************************************************