API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: Apr 08, 2025 Euclid Observatory (spacecraft) -680 https://www.esa.int/Science_Exploration/Space_Science/Euclid BACKGROUND: Euclid was built and operated by the European Space Agency with contributions from NASA. It launched July 01, 2023 @ 15:12 UTC on a SpaceX Falcon 9 from Cape Canaveral, Florida, USA. After a one-month transit, its operational orbit will halo around the Earth-Sun Lagrange point 2 (L2), at an average distance of 1.5 million km from Earth. This location keeps pace with Earth as it orbits the Sun (and also hosts ESA's Gaia and NASA's James Webb space telescopes, among others). Nominal mission lifetime is six years, with the possibility of extension (limited by the amount of cold gas used for propulsion). MISSION: Euclid is a cosmology survey mission, optimised to determine the properties of dark energy and dark matter on universal scales to address key questions: - What is the structure and history of the cosmic web? - What is the nature of dark matter? - How has the expansion of the Universe changed over time? - What is the nature of dark energy? - Is our understanding of gravity complete? In addition, Euclid will perform near-infrared spectroscopy of hundreds of millions of galaxies and stars. This will allow investigation of the chemical and kinematical properties of many targets in detail. Euclid's image quality will be at least four times sharper than that achieved by ground-based sky surveys. SPACECRAFT: 4.7m tall, 3.7 m diameter Two major components: service and payload modules Service module 850 kg Payload module 800 kg Propellant 210 kg Balancing mass 40 kg Service module contains: electric power generation and distribution attitude control data processing electronics propulsion telecommand and telemetry thermal control SCIENCE INSTRUMENTS (payload module): - 1.2-m diameter telescope - Visible-wavelength camera (the VISible instrument, VIS) - Near-Infrared Spectrometer and Photometer, NISP) SPACECRAFT TRAJECTORY Tracking-data based from ESA 2025-Mar-18, predicts thereafter: Trajectory name Start Stop -------------------------------------------- ----------- ----------- euclid_flp_00066_20230701_20310907_v01 2023-Jul-01 2031-Sep-07 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Fri Apr 18 19:49:55 2025 Pasadena, USA / Horizons ******************************************************************************* Target body name: Euclid (spacecraft) (-680) {source: Euclid_current} Center body name: Earth (399) {source: DE441} Center-site name: VdS Remote Observatory, Hakos ******************************************************************************* Start time : A.D. 2024-Oct-31 00:00:00.0000 UT Stop time : A.D. 2024-Nov-01 00:00:00.0000 UT Step-size : 10 minutes ******************************************************************************* Target pole/equ : undefined Target radii : undefined Center geodetic : 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: 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.250418.p250715 EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-APR-18. PREDICTS-> 2025-JUL-14 Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s Table cut-offs 1: Elevation ( 0.0deg=YES),Airmass (>38.000=NO), Daylight (YES) Table cut-offs 2: Solar elongation ( 12.0,180.0=YES),Local Hour Angle( 0.0=NO ) Table cut-offs 3: RA/DEC angular rate ( 0.0=NO ) *************************************************************************************************************************************************************************************************************************************************** Date__(UT)__HR:MN R.A._____(ICRF)_____DEC Azi____(a-app)___Elev APmag S-brt r rdot delta deldot S-O-T /r S-T-O T-O-M/MN_Illu% RA_3sigma DEC_3sigma Sky_motion Sky_mot_PA RelVel-ANG *************************************************************************************************************************************************************************************************************************************************** $$SOE 2024-Oct-31 00:00 03 49 20.30 +09 10 17.8 2.802150 57.479748 n.a. n.a. 1.000756805545 -0.4280995 0.00851868258695 0.0782032 157.9239 /L 21.8929 142.6/ 2.0498 n.a. n.a. 2.1905062 9.2123321 19.123719 2024-Oct-31 00:10 t 03 49 20.53 +09 10 39.3 358.199872 57.493925 n.a. n.a. 1.000755088632 -0.4280561 0.00851903314381 0.0966113 157.9307 /L 21.8862 142.7/ 2.0246 n.a. n.a. 2.1613771 9.3028515 23.466111 2024-Oct-31 00:20 03 49 20.77 +09 11 00.5 353.618308 57.323684 n.a. n.a. 1.000753371892 -0.4280127 0.00851945751071 0.1150046 157.9374 /L 21.8795 142.8/ 1.9998 n.a. n.a. 2.1335347 9.6063151 27.630549 2024-Oct-31 00:30 03 49 21.01 +09 11 21.4 349.104781 56.971887 n.a. n.a. 1.000751655327 -0.4279693 0.00851995555761 0.1333478 157.9440 /L 21.8729 142.9/ 1.9753 n.a. n.a. 2.1071604 10.129898 31.571313 2024-Oct-31 00:40 03 49 21.26 +09 11 42.0 344.702208 56.444268 n.a. n.a. 1.000749938936 -0.4279259 0.00852052701333 0.1516059 157.9506 /L 21.8663 143.0/ 1.9512 n.a. n.a. 2.0825255 10.879666 35.255182 2024-Oct-31 00:50 03 49 21.53 +09 12 02.3 340.446748 55.748988 n.a. n.a. 1.000748222720 -0.4278824 0.00852117146599 0.1697438 157.9572 /L 21.8598 143.1/ 1.9275 n.a. n.a. 2.0599937 11.860169 38.660713 2024-Oct-31 01:00 03 49 21.83 +09 12 22.3 336.366411 54.896057 n.a. n.a. 1.000746506678 -0.4278390 0.00852188836391 0.1877268 157.9635 /L 21.8535 143.2/ 1.9041 n.a. n.a. 2.0400195 13.073917 41.776541 2024-Oct-31 01:10 03 49 22.15 +09 12 42.1 332.480666 53.896707 n.a. n.a. 1.000744790810 -0.4277955 0.00852267701668 0.2055205 157.9698 /L 21.8473 143.3/ 1.8811 n.a. n.a. 2.0231452 14.520739 44.599243 2024-Oct-31 01:20 03 49 22.51 +09 13 01.5 328.800888 52.762795 n.a. n.a. 1.000743075117 -0.4277520 0.00852353659653 0.2230908 157.9759 /L 21.8412 143.4/ 1.8585 n.a. n.a. 2.0099925 16.197061 47.131241 2024-Oct-31 01:30 03 49 22.91 +09 13 20.7 325.331375 51.506291 n.a. n.a. 1.000741359598 -0.4277085 0.00852446614005 0.2404041 157.9818 /L 21.8353 143.4/ 1.8362 n.a. n.a. 2.0012501 18.095170 49.378982 2024-Oct-31 01:40 03 49 23.35 +09 13 39.6 322.070672 50.138877 n.a. n.a. 1.000739644253 -0.4276650 0.00852546455004 0.2574273 157.9875 /L 21.8296 143.5/ 1.8144 n.a. n.a. 1.9976558 20.202547 51.351552 2024-Oct-31 01:50 03 49 23.84 +09 13 58.2 319.012951 48.671656 n.a. n.a. 1.000737929084 -0.4276215 0.00852653059772 0.2741279 157.9931 /L 21.8241 143.6/ 1.7929 n.a. n.a. 1.9999728 22.501387 53.059699 2024-Oct-31 02:00 03 49 24.38 +09 14 16.6 316.149294 47.114978 n.a. n.a. 1.000736214088 -0.4275780 0.00852766292524 0.2904742 157.9983 /L 21.8189 143.7/ 1.7719 n.a. n.a. 2.0089621 24.968447 54.515229 2024-Oct-31 02:10 03 49 24.98 +09 14 34.7 313.468791 45.478337 n.a. n.a. 1.000734499268 -0.4275345 0.00852886004829 0.3064347 158.0034 /L 21.8139 143.8/ 1.7512 n.a. n.a. 2.0253507 27.575340 55.730678 2024-Oct-31 02:20 03 49 25.64 +09 14 52.5 310.959423 43.770343 n.a. n.a. 1.000732784622 -0.4274909 0.00853012035912 0.3219793 158.0081 /L 21.8091 143.9/ 1.7310 n.a. n.a. 2.0497996 30.289325 56.719152 2024-Oct-31 02:30 03 49 26.37 +09 15 10.1 308.608725 41.998736 n.a. n.a. 1.000731070151 -0.4274474 0.00853144212971 0.3370784 158.0126 /L 21.8047 144.0/ 1.7111 n.a. n.a. 2.0828731 33.074603 57.494260 2024-Oct-31 02:40 03 49 27.17 +09 15 27.5 306.404270 40.170432 n.a. n.a. 1.000729355855 -0.4274038 0.00853282351519 0.3517031 158.0167 /L 21.8005 144.1/ 1.6917 n.a. n.a. 2.1250141 35.893995 58.070054 2024-Oct-31 02:50 A 03 49 28.05 +09 15 44.6 304.333997 38.291579 n.a. n.a. 1.000727641734 -0.4273602 0.00853426255755 0.3658259 158.0206 /L 21.7967 144.1/ 1.6727 n.a. n.a. 2.1765267 38.710804 58.460936 2024-Oct-31 03:00 A 03 49 29.01 +09 16 01.5 302.386419 36.367629 n.a. n.a. 1.000725927787 -0.4273166 0.00853575718942 0.3794199 158.0241 /L 21.7932 144.2/ 1.6540 n.a. n.a. 2.2375683 41.490628 58.681518 2024-Oct-31 03:10 A 03 49 30.05 +09 16 18.2 300.550744 34.403410 n.a. n.a. 1.000724214016 -0.4272730 0.00853730523825 0.3924594 158.0272 /L 21.7900 144.3/ 1.6358 n.a. n.a. 2.3081509 44.202891 58.746423 2024-Oct-31 03:20 Nm 03 49 31.18 +09 16 34.7 298.816931 32.403190 n.a. n.a. 1.000722500419 -0.4272294 0.00853890443052 0.4049198 158.0300 /L 21.7872 144.4/ 1.6180 n.a. n.a. 2.3881516 46.821920 58.670060 2024-Oct-31 03:30 Nm 03 49 32.40 +09 16 50.9 297.175700 30.370748 n.a. n.a. 1.000720786998 -0.4271858 0.00854055239627 0.4167777 158.0324 /L 21.7848 144.4/ 1.6006 n.a. n.a. 2.4773284 49.327513 58.466397 2024-Oct-31 03:40 Nm 03 49 33.71 +09 17 07.0 295.618518 28.309427 n.a. n.a. 1.000719073751 -0.4271422 0.00854224667372 0.4280107 158.0344 /L 21.7828 144.5/ 1.5835 n.a. n.a. 2.5753398 51.705004 58.148750 2024-Oct-31 03:50 Cm 03 49 35.13 +09 17 22.9 294.137558 26.222192 n.a. n.a. 1.000717360680 -0.4270985 0.00854398471415 0.4385978 158.0360 /L 21.7812 144.6/ 1.5669 n.a. n.a. 2.6817665 53.944928 57.729617 2024-Oct-31 04:00 Cm 03 49 36.64 +09 17 38.7 292.725654 24.111674 n.a. n.a. 1.000715647783 -0.4270549 0.00854576388683 0.4485192 158.0372 /L 21.7800 144.6/ 1.5507 n.a. n.a. 2.7961308 56.042412 57.220563 >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2024-Oct-31 18:30 03 55 55.04 +09 47 27.8 78.935093 0.726738 n.a. n.a. 1.000567300932 -0.4232139 0.00859451463617 -0.3241631 157.1802 /L 22.6290 148.1/ 0.6607 n.a. n.a. 4.9191677 55.195128 -32.38372 2024-Oct-31 18:40 03 55 57.71 +09 47 56.0 77.928363 2.970232 n.a. n.a. 1.000565603613 -0.4231693 0.00859321843224 -0.3220911 157.1776 /L 22.6316 148.2/ 0.6475 n.a. n.a. 4.7724558 53.999958 -33.00936 2024-Oct-31 18:50 03 56 00.26 +09 48 24.1 76.900576 5.205602 n.a. n.a. 1.000563906474 -0.4231246 0.00859193212200 -0.3192301 157.1755 /L 22.6337 148.3/ 0.6344 n.a. n.a. 4.6278946 52.749772 -33.58750 2024-Oct-31 19:00 03 56 02.68 +09 48 52.2 75.848480 7.431921 n.a. n.a. 1.000562209514 -0.4230800 0.00859065886024 -0.3155851 157.1739 /L 22.6354 148.4/ 0.6212 n.a. n.a. 4.4858493 51.443117 -34.11342 2024-Oct-31 19:10 03 56 05.00 +09 49 20.2 74.768655 9.648179 n.a. n.a. 1.000560512732 -0.4230353 0.00858940177895 -0.3111625 157.1727 /L 22.6366 148.5/ 0.6080 n.a. n.a. 4.3466771 50.078836 -34.58191 2024-Oct-31 19:20 03 56 07.19 +09 49 48.1 73.657476 11.853275 n.a. n.a. 1.000558816131 -0.4229906 0.00858816398132 -0.3059702 157.1720 /L 22.6373 148.6/ 0.5948 n.a. n.a. 4.2107243 48.656147 -34.98719 2024-Oct-31 19:30 03 56 09.27 +09 50 15.9 72.511080 14.046001 n.a. n.a. 1.000557119708 -0.4229459 0.00858694853581 -0.3000177 157.1718 /L 22.6375 148.7/ 0.5817 n.a. n.a. 4.0783231 47.174740 -35.32292 2024-Oct-31 19:40 03 56 11.23 +09 50 43.6 71.325326 16.225026 n.a. n.a. 1.000555423465 -0.4229012 0.00858575847028 -0.2933158 157.1720 /L 22.6373 148.8/ 0.5685 n.a. n.a. 3.9497883 45.634875 -35.58209 2024-Oct-31 19:50 03 56 13.08 +09 51 11.3 70.095756 18.388883 n.a. n.a. 1.000553727401 -0.4228565 0.00858459676609 -0.2858767 157.1727 /L 22.6367 148.9/ 0.5554 n.a. n.a. 3.8254139 44.037498 -35.75700 2024-Oct-31 20:00 03 56 14.82 +09 51 38.8 68.817555 20.535942 n.a. n.a. 1.000552031516 -0.4228118 0.00858346635236 -0.2777144 157.1737 /L 22.6357 148.9/ 0.5424 n.a. n.a. 3.7054686 42.384346 -35.83918 2024-Oct-31 20:10 03 56 16.45 +09 52 06.1 67.485498 22.664392 n.a. n.a. 1.000550335811 -0.4227670 0.00858237010032 -0.2688438 157.1753 /L 22.6342 149.0/ 0.5294 n.a. n.a. 3.5901922 40.678065 -35.81935 2024-Oct-31 20:20 03 56 17.98 +09 52 33.3 66.093912 24.772213 n.a. n.a. 1.000548640286 -0.4227223 0.00858131081776 -0.2592814 157.1772 /L 22.6323 149.1/ 0.5165 n.a. n.a. 3.4797905 38.922318 -35.68738 2024-Oct-31 20:30 03 56 19.41 +09 53 00.3 64.636622 26.857147 n.a. n.a. 1.000546944940 -0.4226775 0.00858029124348 -0.2490453 157.1795 /L 22.6300 149.2/ 0.5037 n.a. n.a. 3.3744317 37.121872 -35.43220 2024-Oct-31 20:40 03 56 20.73 +09 53 27.2 63.106902 28.916662 n.a. n.a. 1.000545249773 -0.4226327 0.00857931404207 -0.2381544 157.1822 /L 22.6273 149.3/ 0.4909 n.a. n.a. 3.2742416 35.282679 -35.04179 2024-Oct-31 20:50 03 56 21.96 +09 53 53.9 61.497432 30.947919 n.a. n.a. 1.000543554786 -0.4225880 0.00857838179863 -0.2266293 157.1853 /L 22.6243 149.5/ 0.4783 n.a. n.a. 3.1793001 33.411919 -34.50312 2024-Oct-31 21:00 03 56 23.09 +09 54 20.3 59.800253 32.947723 n.a. n.a. 1.000541859979 -0.4225432 0.00857749701378 -0.2144916 157.1888 /L 22.6209 149.6/ 0.4657 n.a. n.a. 3.0896377 31.518007 -33.80216 2024-Oct-31 21:10 03 56 24.14 +09 54 46.6 58.006736 34.912476 n.a. n.a. 1.000540165352 -0.4224984 0.00857666209869 -0.2017643 157.1926 /L 22.6171 149.7/ 0.4533 n.a. n.a. 3.0052335 29.610569 -32.92390 2024-Oct-31 21:20 03 56 25.10 +09 55 12.7 56.107568 36.838125 n.a. n.a. 1.000538470905 -0.4224535 0.00857587937040 -0.1884714 157.1967 /L 22.6131 149.8/ 0.4410 n.a. n.a. 2.9260135 27.700362 -31.85237 2024-Oct-31 21:30 03 56 25.97 +09 55 38.5 54.092758 38.720104 n.a. n.a. 1.000536776637 -0.4224087 0.00857515104728 -0.1746381 157.2011 /L 22.6087 149.9/ 0.4288 n.a. n.a. 2.8518510 25.799161 -30.57082 2024-Oct-31 21:40 03 56 26.77 +09 56 04.1 51.951685 40.553270 n.a. n.a. 1.000535082549 -0.4223639 0.00857447924460 -0.1602905 157.2059 /L 22.6040 150.0/ 0.4168 n.a. n.a. 2.7825682 23.919597 -29.06192 2024-Oct-31 21:50 03 56 27.49 +09 56 29.4 49.673203 42.331840 n.a. n.a. 1.000533388642 -0.4223190 0.00857386597045 -0.1454559 157.2109 /L 22.5990 150.1/ 0.4049 n.a. n.a. 2.7179390 22.074967 -27.30812 2024-Oct-31 22:00 03 56 28.15 +09 56 54.5 47.245810 44.049327 n.a. n.a. 1.000531694914 -0.4222742 0.00857331312168 -0.1301626 157.2162 /L 22.5938 150.2/ 0.3932 n.a. n.a. 2.6576944 20.279026 -25.29229 2024-Oct-31 22:10 03 56 28.74 +09 57 19.3 44.657929 45.698489 n.a. n.a. 1.000530001366 -0.4222293 0.00857282248023 -0.1144395 157.2217 /L 22.5883 150.3/ 0.3816 n.a. n.a. 2.6015284 18.545769 -22.99850 2024-Oct-31 22:20 03 56 29.26 +09 57 43.8 41.898304 47.271280 n.a. n.a. 1.000528307999 -0.4221844 0.00857239570956 -0.0983168 157.2275 /L 22.5826 150.4/ 0.3703 n.a. n.a. 2.5491058 16.889218 -20.41323 2024-Oct-31 22:30 03 56 29.73 +09 58 08.1 38.956563 48.758835 n.a. n.a. 1.000526614811 -0.4221395 0.00857203435136 -0.0818251 157.2334 /L 22.5767 150.5/ 0.3591 n.a. n.a. 2.5000713 15.323235 -17.52695 2024-Oct-31 22:40 03 56 30.15 +09 58 32.1 35.823953 50.151488 n.a. n.a. 1.000524921804 -0.4220946 0.00857173982253 -0.0649959 157.2396 /L 22.5706 150.6/ 0.3481 n.a. n.a. 2.4540589 13.861368 -14.33602 2024-Oct-31 22:50 03 56 30.52 +09 58 55.8 32.494264 51.438846 n.a. n.a. 1.000523228977 -0.4220497 0.00857151341232 -0.0478613 157.2459 /L 22.5643 150.7/ 0.3373 n.a. n.a. 2.4107024 12.516734 -10.84492 2024-Oct-31 23:00 03 56 30.85 +09 59 19.2 28.964926 52.609930 n.a. n.a. 1.000521536330 -0.4220048 0.00857135627977 -0.0304542 157.2524 /L 22.5579 150.8/ 0.3267 n.a. n.a. 2.3696457 11.301952 -7.068508 2024-Oct-31 23:10 03 56 31.15 +09 59 42.3 25.238215 53.653406 n.a. n.a. 1.000519843863 -0.4219598 0.00857126945145 -0.0128079 157.2590 /L 22.5514 150.9/ 0.3163 n.a. n.a. 2.3305532 10.229115 -3.033919 2024-Oct-31 23:20 03 56 31.41 +10 00 05.1 21.322448 54.557920 n.a. n.a. 1.000518151577 -0.4219149 0.00857125381939 0.0050440 157.2657 /L 22.5447 151.0/ 0.3061 n.a. n.a. 2.2931199 9.3098010 1.2184872 2024-Oct-31 23:30 03 56 31.65 +10 00 27.5 17.232992 55.312529 n.a. n.a. 1.000516459471 -0.4218699 0.00857131013929 0.0230671 157.2724 /L 22.5380 151.1/ 0.2961 n.a. n.a. 2.2570816 8.5551176 5.6355798 2024-Oct-31 23:40 03 56 31.86 +10 00 49.7 12.992864 55.907219 n.a. n.a. 1.000514767546 -0.4218249 0.00857143902905 0.0412270 157.2793 /L 22.5312 151.2/ 0.2863 n.a. n.a. 2.2222235 7.9757564 10.153733 2024-Oct-31 23:50 03 56 32.06 +10 01 11.6 8.632678 56.333469 n.a. n.a. 1.000513075801 -0.4217799 0.00857164096752 0.0594889 157.2862 /L 22.5244 151.3/ 0.2768 n.a. n.a. 2.1883896 7.5820520 14.702822 2024-Nov-01 00:00 03 56 32.25 +10 01 33.1 4.189773 56.584799 n.a. n.a. 1.000511384237 -0.4217350 0.00857191629356 0.0778178 157.2931 /L 22.5175 151.5/ 0.2674 n.a. n.a. 2.1554904 7.3840227 19.211361 $$EOE *************************************************************************************************************************************************************************************************************************************************** Column meaning: TIME Times PRIOR to 1962 are UT1, a mean-solar time closely related to the prior but now-deprecated GMT. Times AFTER 1962 are in UTC, the current civil or "wall-clock" time-scale. UTC is kept within 0.9 seconds of UT1 using integer leap-seconds for 1972 and later years. Conversion from the internal Barycentric Dynamical Time (TDB) of solar system dynamics to the non-uniform civil UT time-scale requested for output has not been determined for UTC times after the next July or January 1st. Therefore, the last known leap-second is used as a constant over future intervals. Time tags refer to the UT time-scale conversion from TDB on Earth regardless of observer location within the solar system, although clock rates may differ due to the local gravity field and no analog to "UT" may be defined for that location. Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank (" ") denotes an A.D. date. CALENDAR SYSTEM Mixed calendar mode was active such that calendar dates after AD 1582-Oct-15 (if any) are in the modern Gregorian system. Dates prior to 1582-Oct-5 (if any) are in the Julian calendar system, which is automatically extended for dates prior to its adoption on 45-Jan-1 BC. The Julian calendar is useful for matching historical dates. The Gregorian calendar more accurately corresponds to the Earth's orbital motion and seasons. A "Gregorian-only" calendar mode is available if such physical events are the primary interest. NOTE: "n.a." in output means quantity "not available" at the print-time. SOLAR PRESENCE (OBSERVING SITE) Time tag is followed by a blank, then a solar-presence condition code: '*' Daylight (refracted solar upper-limb on or above apparent horizon) 'C' Civil twilight/dawn 'N' Nautical twilight/dawn 'A' Astronomical twilight/dawn ' ' Night OR geocentric ephemeris LUNAR PRESENCE WITH TARGET RISE/TRANSIT/SET EVENT MARKER (OBSERVING SITE) The solar-presence code column is immediately followed by another marker: 'm' Refracted upper-limb of Moon on or above apparent horizon ' ' Refracted upper-limb of Moon below apparent horizon OR geocentric The lunar presence marker (an ongoing state) can be over-ridden by a target event marker if an event has occurred since the last output step: 'r' Rise (target body on or went above cut-off RTS elevation) 'e' Elevation max (target body maximum elevation angle has occurred) 't' Transit (target body at or passed through observer meridian) 's' Set (target body on or went below cut-off RTS elevation) RTS MARKERS (TVH) Rise and set are with respect to the reference ellipsoid true visual horizon defined by the elevation cut-off angle. Horizon dip and yellow-light refraction (Earth only) are considered. Accuracy is < or = to twice the requested search step-size. 'R.A._____(ICRF)_____DEC' = Astrometric right ascension and declination of the target center with respect to the observing site (coordinate origin) in the reference frame of the planetary ephemeris (ICRF). Compensated for down-leg light-time delay aberration. Units: RA in hours-minutes-seconds of time, HH MM SS.ff{ffff} DEC in degrees-minutes-seconds of arc, sDD MN SC.f{ffff} 'Azi____(a-app)___Elev' = Airless apparent azimuth and elevation of target center. Compensated for light-time, the gravitational deflection of light, stellar aberration, precession and nutation. Azimuth is measured clockwise from north: North(0) -> East(90) -> South(180) -> West(270) -> North (360) Elevation angle is with respect to a plane perpendicular to the reference surface local zenith direction. TOPOCENTRIC ONLY. Units: DEGREES 'APmag S-brt' = The targets' approximate apparent visual magnitude and surface brightness. For planets and natural satellites, output is restricted to solar phase angles covered by observational data. Outside the observed phase angle range, "n.a." may be output to avoid extrapolation beyond the limit of model validity. For Earth-based observers, the estimated dimming due to atmospheric absorption (extinction) is available as a separate, requestable quantity. Surface brightness is the average airless visual magnitude of a square-arcsecond of the illuminated portion of the apparent disk. It is computed only if the target radius is known. Units: MAGNITUDES & MAGNITUDES PER SQUARE ARCSECOND 'r rdot' = The Sun's apparent range ("r", light-time aberrated) and range-rate ("rdot") relative to the target center, as seen by the observer. A positive "rdot" means the target center was moving away from the Sun, negative means moving toward the Sun. Units: AU and KM/S 'delta deldot' = Apparent range ("delta", light-time aberrated) and range-rate ("delta-dot") of the target center relative to the observer. A positive "deldot" means the target center is moving away from the observer, negative indicates movement toward the observer. Units: AU and KM/S 'S-O-T /r' = Sun-Observer-Target apparent SOLAR ELONGATION ANGLE seen from the observers' location at print-time. The '/r' column provides a code indicating the targets' apparent position relative to the Sun in the observers' sky, as described below: Case A: For an observing location on the surface of a rotating body, that body rotational sense is considered: /T indicates target TRAILS Sun (evening sky: rises and sets AFTER Sun) /L indicates target LEADS Sun (morning sky: rises and sets BEFORE Sun) Case B: For an observing point that does not have a rotational model (such as a spacecraft), the "leading" and "trailing" condition is defined by the observers' heliocentric ORBITAL motion: * If continuing in the observers' current direction of heliocentric motion would encounter the targets' apparent longitude first, followed by the Sun's, the target LEADS the Sun as seen by the observer. * If the Sun's apparent longitude would be encountered first, followed by the targets', the target TRAILS the Sun. Two other codes can be output: /* indicates observer is Sun-centered (undefined) /? Target is aligned with Sun center (no lead or trail) The S-O-T solar elongation angle is numerically the minimum separation angle of the Sun and target in the sky in any direction. It does NOT indicate the amount of separation in the leading or trailing directions, which would be defined along the equator of a spherical coordinate system. Units: DEGREES 'S-T-O' = The Sun-Target-Observer angle; the interior vertex angle at target center formed by a vector from the target to the apparent center of the Sun (at reflection time on the target) and the apparent vector from target to the observer at print-time. Slightly different from true PHASE ANGLE (requestable separately) at the few arcsecond level in that it includes stellar aberration on the down-leg from target to observer. Units: DEGREES 'T-O-M/MN_Illu%' = Target-Observer-Moon LUNAR ELONGATION angle and illuminated percentage. The apparent lunar elongation angle between target body center and Moon center, seen from the observing site, along with fraction of the lunar disk illuminated by the Sun. A negative lunar elongation angle indicates the target center is behind the Moon. Units: DEGREES & PERCENT 'RA_3sigma DEC_3sigma' = Uncertainty in Right-Ascension and Declination. Output values are the formal +/- 3 standard-deviations (sigmas) around nominal position. Units: ARCSECONDS 'Sky_motion Sky_mot_PA RelVel-ANG' = Total apparent angular rate of the target in the plane-of-sky. "Sky_mot_PA" is the position angle of the target's direction of motion in the plane-of-sky, measured counter-clockwise from the apparent of-date north pole direction. "RelVel-ANG" is the flight path angle of the target's relative motion with respect to the observer's line-of-sight, in the range [-90,+90], where positive values indicate motion away from the observer, negative values are toward the observer: -90 = target is moving directly toward the observer 0 = target is moving at right angles to the observer's line-of-sight +90 = target is moving directly away from the observer UNITS: ARCSECONDS/MINUTE, DEGREES, DEGREES Computations by ... Solar System Dynamics Group, Horizons On-Line Ephemeris System 4800 Oak Grove Drive, Jet Propulsion Laboratory Pasadena, CA 91109 USA General site: https://ssd.jpl.nasa.gov/ Mailing list: https://ssd.jpl.nasa.gov/email_list.html System news : https://ssd.jpl.nasa.gov/horizons/news.html User Guide : https://ssd.jpl.nasa.gov/horizons/manual.html Connect : browser https://ssd.jpl.nasa.gov/horizons/app.html#/x API https://ssd-api.jpl.nasa.gov/doc/horizons.html command-line telnet ssd.jpl.nasa.gov 6775 e-mail/batch https://ssd.jpl.nasa.gov/ftp/ssd/horizons_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov ***************************************************************************************************************************************************************************************************************************************************