API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: Dec 06, 2024 Chandra Spacecraft (X-ray observatory) / (Earth) -151 http://xrtpub.harvard.edu/index.html Chandra X-ray Observatory: Deployment (STS-93) = July 23, 1999 Data storage = 1.8 gbs Science mission = ~5 years Length (sun shade open) = 45.3 m Orbital check-out = 2 months Length (sun shade clsd) = 38.7 m ORBITAL DATA: Inclination = 28.5 degrees Orbital period = ~64 hours Apogee altitude = ~ 86,487 km Observing time / orbit = ~55 hours Perigee altitude = ~ 5,999 km WEIGHTS & PROPULSION: Dry = 10,560 lbs Propellant = 2,153 lbs Pressurant = 10 lb Total launch weight = 12,930 lb Engines = 4 Thrust per engine = 105 lb SPACECRAFT TRAJECTORY (from CFA): Trajectory after 2024-Dec-03 is a prediction Trajectory name Start Stop ---------------------------- ----------- ----------- cxo_99219_06045 1999-Aug-07 2006-Feb-14 cxo_06002_10103 2006-Feb-03 2010-Feb-25 CXO_10056_25126 2010-Feb-25 2025-Jun-04 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Thu Dec 12 02:02:30 2024 Pasadena, USA / Horizons ******************************************************************************* Target body name: Chandra Observatory (spacecraft) (-151) {source: chandra_merged} Center body name: Earth (399) {source: chandra_merged} Center-site name: SATINO Remote Observatory, Haute Provence ******************************************************************************* 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 : 5.7124, 43.9320269, .703985 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 5.7124, 4601.22659, 4403.14405 {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: chandra_merged} Rel. light bend : Sun {source: chandra_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 .....< 2024-Nov-30 03:00 17 21 15.93 +38 41 58.7 29.896006 0.047596 n.a. n.a. 0.985885236091 -0.7754132 0.00083945799761 0.8181710 61.7648 /T 118.1924 67.3/ 1.2747 n.a. n.a. 87.864888 93.995805 42.538168 2024-Nov-30 03:10 17 22 30.10 +38 40 56.6 31.418189 0.840128 n.a. n.a. 0.985882139110 -0.7689396 0.00084269928996 0.7981776 61.8100 /T 118.1470 67.4/ 1.2588 n.a. n.a. 86.246138 93.824859 42.252876 2024-Nov-30 03:20 17 23 42.88 +38 39 58.2 32.925317 1.671636 n.a. n.a. 0.985879067983 -0.7625203 0.00084586099812 0.7784868 61.8564 /T 118.1004 67.5/ 1.2433 n.a. n.a. 84.625095 93.659062 41.974962 2024-Nov-30 03:30 17 24 54.28 +38 39 03.3 34.417016 2.541307 n.a. n.a. 0.985876022495 -0.7561540 0.00084894435728 0.7591093 61.9036 /T 118.0530 67.6/ 1.2281 n.a. n.a. 83.001933 93.499146 41.705069 2024-Nov-30 03:40 17 26 04.30 +38 38 11.6 35.892998 3.448306 n.a. n.a. 0.985873002436 -0.7498392 0.00085195064613 0.7400561 61.9517 /T 118.0047 67.7/ 1.2133 n.a. n.a. 81.376890 93.345892 41.443873 2024-Nov-30 03:50 17 27 12.92 +38 37 23.1 37.353061 4.391779 n.a. n.a. 0.985870007604 -0.7435747 0.00085488118613 0.7213377 62.0005 /T 117.9558 67.8/ 1.1988 n.a. n.a. 79.750271 93.200133 41.192085 2024-Nov-30 04:00 17 28 20.16 +38 36 37.5 38.797082 5.370858 n.a. n.a. 0.985867037797 -0.7373592 0.00085773734074 0.7029644 62.0498 /T 117.9063 67.9/ 1.1846 n.a. n.a. 78.122444 93.062764 40.950450 2024-Nov-30 04:10 17 29 26.01 +38 35 54.7 40.225019 6.384667 n.a. n.a. 0.985864092823 -0.7311915 0.00086052051450 0.6849463 62.0996 /T 117.8564 68.0/ 1.1707 n.a. n.a. 76.493842 92.934741 40.719748 2024-Nov-30 04:20 17 30 30.47 +38 35 14.3 41.636907 7.432322 n.a. n.a. 0.985861172493 -0.7250703 0.00086323215202 0.6672934 62.1496 /T 117.8061 68.1/ 1.1572 n.a. n.a. 74.864964 92.817094 40.500799 2024-Nov-30 04:30 17 31 33.54 +38 34 36.3 43.032853 8.512934 n.a. n.a. 0.985858276621 -0.7189945 0.00086587373684 0.6500151 62.1999 /T 117.7557 68.1/ 1.1440 n.a. n.a. 73.236378 92.710933 40.294460 2024-Nov-30 04:40 17 32 35.22 +38 34 00.4 44.413033 9.625617 n.a. n.a. 0.985855405028 -0.7129630 0.00086844679017 0.6331207 62.2503 /T 117.7052 68.2/ 1.1311 n.a. n.a. 71.608716 92.617450 40.101625 2024-Nov-30 04:50 17 33 35.51 +38 33 26.4 45.777694 10.769481 n.a. n.a. 0.985852557539 -0.7069746 0.00087095286958 0.6166190 62.3006 /T 117.6548 68.3/ 1.1186 n.a. n.a. 69.982680 92.537937 39.923231 2024-Nov-30 05:00 17 34 34.41 +38 32 54.0 47.127146 11.943646 n.a. n.a. 0.985849733984 -0.7010283 0.00087339356747 0.6005187 62.3507 /T 117.6045 68.4/ 1.1063 n.a. n.a. 68.359041 92.473784 39.760250 2024-Nov-30 05:10 A 17 35 31.93 +38 32 23.0 48.461761 13.147233 n.a. n.a. 0.985846934194 -0.6951231 0.00087577050957 0.5848277 62.4005 /T 117.5545 68.5/ 1.0944 n.a. n.a. 66.738640 92.426497 39.613694 2024-Nov-30 05:20 A 17 36 28.06 +38 31 53.2 49.781971 14.379373 n.a. n.a. 0.985844158008 -0.6892579 0.00087808535321 0.5695537 62.4500 /T 117.5049 68.6/ 1.0827 n.a. n.a. 65.122393 92.397705 39.484612 2024-Nov-30 05:30 A 17 37 22.81 +38 31 24.3 51.088269 15.639206 n.a. n.a. 0.985841405266 -0.6834318 0.00088033978558 0.5547040 62.4989 /T 117.4558 68.7/ 1.0714 n.a. n.a. 63.511289 92.389171 39.374088 2024-Nov-30 05:40 A 17 38 16.19 +38 30 56.1 52.381202 16.925882 n.a. n.a. 0.985838675816 -0.6776437 0.00088253552179 0.5402852 62.5472 /T 117.4074 68.7/ 1.0603 n.a. n.a. 61.906394 92.402801 39.283235 2024-Nov-30 05:50 N 17 39 08.20 +38 30 28.4 53.661376 18.238560 n.a. n.a. 0.985835969504 -0.6718928 0.00088467430295 0.5263037 62.5947 /T 117.3597 68.8/ 1.0495 n.a. n.a. 60.308856 92.440663 39.213193 2024-Nov-30 06:00 N 17 39 58.85 +38 30 00.9 54.929450 19.576414 n.a. n.a. 0.985833286185 -0.6661781 0.00088675789406 0.5127650 62.6415 /T 117.3129 68.9/ 1.0390 n.a. n.a. 58.719904 92.504994 39.165123 2024-Nov-30 06:10 Nm 17 40 48.13 +38 29 33.3 56.186144 20.938628 n.a. n.a. 0.985830625715 -0.6604988 0.00088878808181 0.4996743 62.6872 /T 117.2670 69.0/ 1.0288 n.a. n.a. 57.140853 92.598215 39.140196 2024-Nov-30 06:20 Cm 17 41 36.08 +38 29 05.4 57.432231 22.324399 n.a. n.a. 0.985827987954 -0.6548540 0.00089076667233 0.4870361 62.7319 /T 117.2221 69.0/ 1.0188 n.a. n.a. 55.573110 92.722945 39.139584 2024-Nov-30 06:30 Cm 17 42 22.68 +38 28 36.9 58.668547 23.732939 n.a. n.a. 0.985825372764 -0.6492428 0.00089269548886 0.4748545 62.7755 /T 117.1785 69.1/ 1.0091 n.a. n.a. 54.018174 92.882014 39.164446 2024-Nov-30 06:40 Cm 17 43 07.95 +38 28 07.6 59.895989 25.163469 n.a. n.a. 0.985822780014 -0.6436644 0.00089457636923 0.4631328 62.8178 /T 117.1361 69.2/ 0.9996 n.a. n.a. 52.477648 93.078477 39.215909 >..... Daylight Cut-off Requested .....< 2024-Nov-30 16:10 C 18 04 15.89 +35 46 59.4 273.567289 53.557692 n.a. n.a. 0.985709029312 -0.3598999 0.00097275207938 0.3284010 61.9123 /T 118.0379 68.6/ 0.5921 n.a. n.a. 42.498763 144.28752 33.308460 2024-Nov-30 16:20 C 18 04 36.51 +35 41 11.5 274.936643 51.774378 n.a. n.a. 0.985707595172 -0.3552490 0.00097406626935 0.3268676 61.8536 /T 118.0965 68.5/ 0.5838 n.a. n.a. 43.319232 143.74601 32.650334 2024-Nov-30 16:30 C 18 04 57.77 +35 35 19.3 276.268769 49.995476 n.a. n.a. 0.985706179679 -0.3506016 0.00097537367372 0.3250149 61.7951 /T 118.1550 68.4/ 0.5753 n.a. n.a. 44.142033 143.17586 31.981329 2024-Nov-30 16:40 N 18 05 19.71 +35 29 23.2 277.570043 48.221825 n.a. n.a. 0.985704782819 -0.3459575 0.00097667298356 0.3228289 61.7368 /T 118.2132 68.4/ 0.5668 n.a. n.a. 44.966675 142.58025 31.300852 2024-Nov-30 16:50 N 18 05 42.35 +35 23 23.5 278.845883 46.454222 n.a. n.a. 0.985703404578 -0.3413164 0.00097796283626 0.3202968 61.6788 /T 118.2712 68.3/ 0.5582 n.a. n.a. 45.792680 141.96214 30.608351 2024-Nov-30 17:00 N 18 06 05.69 +35 17 20.3 280.100948 44.693423 n.a. n.a. 0.985702044947 -0.3366779 0.00097924181839 0.3174062 61.6213 /T 118.3287 68.2/ 0.5496 n.a. n.a. 46.619574 141.32432 29.903317 2024-Nov-30 17:10 A 18 06 29.76 +35 11 13.9 281.339276 42.940163 n.a. n.a. 0.985700703915 -0.3320416 0.00098050846847 0.3141455 61.5643 /T 118.3856 68.1/ 0.5409 n.a. n.a. 47.446883 140.66938 29.185288 2024-Nov-30 17:20 A 18 06 54.57 +35 05 04.6 282.564404 41.195155 n.a. n.a. 0.985699381474 -0.3274073 0.00098176127998 0.3105037 61.5080 /T 118.4419 68.1/ 0.5322 n.a. n.a. 48.274124 139.99977 28.453852 2024-Nov-30 17:30 A 18 07 20.14 +34 58 52.5 283.779459 39.459102 n.a. n.a. 0.985698077617 -0.3227746 0.00098299870427 0.3064709 61.4524 /T 118.4974 68.0/ 0.5234 n.a. n.a. 49.100805 139.31776 27.708648 2024-Nov-30 17:40 A 18 07 46.48 +34 52 38.0 284.987227 37.732701 n.a. n.a. 0.985696792337 -0.3181431 0.00098421915366 0.3020376 61.3977 /T 118.5521 67.9/ 0.5146 n.a. n.a. 49.926421 138.62547 26.949366 2024-Nov-30 17:50 18 08 13.60 +34 46 21.3 286.190216 36.016646 n.a. n.a. 0.985695525632 -0.3135126 0.00098542100451 0.2971952 61.3439 /T 118.6058 67.8/ 0.5058 n.a. n.a. 50.750451 137.92488 26.175751 2024-Nov-30 18:00 18 08 41.50 +34 40 02.6 287.390699 34.311632 n.a. n.a. 0.985694277496 -0.3088827 0.00098660260037 0.2919361 61.2912 /T 118.6585 67.8/ 0.4969 n.a. n.a. 51.572353 137.21782 25.387597 2024-Nov-30 18:10 18 09 10.20 +34 33 42.3 288.590756 32.618363 n.a. n.a. 0.985693047930 -0.3042530 0.00098776225510 0.2862531 61.2397 /T 118.7100 67.7/ 0.4881 n.a. n.a. 52.391570 136.50601 24.584749 2024-Nov-30 18:20 18 09 39.70 +34 27 20.4 289.792301 30.937546 n.a. n.a. 0.985691836932 -0.2996234 0.00098889825610 0.2801401 61.1894 /T 118.7603 67.6/ 0.4792 n.a. n.a. 53.207521 135.79102 23.767104 2024-Nov-30 18:30 18 10 10.01 +34 20 57.3 290.997112 29.269903 n.a. n.a. 0.985690644502 -0.2949933 0.00099000886751 0.2735916 61.1404 /T 118.8092 67.6/ 0.4703 n.a. n.a. 54.019608 135.07431 22.934605 2024-Nov-30 18:40 18 10 41.13 +34 14 33.3 292.206852 27.616168 n.a. n.a. 0.985689470645 -0.2903625 0.00099109233340 0.2666031 61.0929 /T 118.8567 67.5/ 0.4615 n.a. n.a. 54.827212 134.35725 22.087243 2024-Nov-30 18:50 18 11 13.05 +34 08 08.5 293.423082 25.977091 n.a. n.a. 0.985688315362 -0.2857307 0.00099214688101 0.2591709 61.0469 /T 118.9027 67.4/ 0.4527 n.a. n.a. 55.629692 133.64107 21.225055 2024-Nov-30 19:00 18 11 45.79 +34 01 43.1 294.647282 24.353441 n.a. n.a. 0.985687178659 -0.2810975 0.00099317072394 0.2512917 61.0024 /T 118.9471 67.3/ 0.4439 n.a. n.a. 56.426394 132.92693 20.348118 2024-Nov-30 19:10 18 12 19.34 +33 55 17.5 295.880858 22.746004 n.a. n.a. 0.985686060541 -0.2764626 0.00099416206541 0.2429636 60.9597 /T 118.9898 67.3/ 0.4351 n.a. n.a. 57.216641 132.21588 19.456554 2024-Nov-30 19:20 18 12 53.70 +33 48 51.8 297.125154 21.155592 n.a. n.a. 0.985684961017 -0.2718257 0.00099511910136 0.2341851 60.9187 /T 119.0308 67.2/ 0.4264 n.a. n.a. 57.999745 131.50888 18.550522 2024-Nov-30 19:30 18 13 28.86 +33 42 26.2 298.381459 19.583039 n.a. n.a. 0.985683880095 -0.2671864 0.00099604002372 0.2249555 60.8795 /T 119.0699 67.2/ 0.4177 n.a. n.a. 58.775002 130.80682 17.630218 2024-Nov-30 19:40 18 14 04.82 +33 36 01.0 299.651016 18.029203 n.a. n.a. 0.985682817786 -0.2625444 0.00099692302343 0.2152750 60.8423 /T 119.1072 67.1/ 0.4091 n.a. n.a. 59.541695 130.11050 16.695875 2024-Nov-30 19:50 18 14 41.57 +33 29 36.4 300.935021 16.494971 n.a. n.a. 0.985681774100 -0.2578994 0.00099776629366 0.2051446 60.8070 /T 119.1424 67.0/ 0.4006 n.a. n.a. 60.299098 129.42064 15.747756 2024-Nov-30 20:00 18 15 19.11 +33 23 12.5 302.234634 14.981260 n.a. n.a. 0.985680749050 -0.2532510 0.00099856803279 0.1945659 60.7737 /T 119.1757 67.0/ 0.3921 n.a. n.a. 61.046475 128.73792 14.786159 2024-Nov-30 20:10 18 15 57.42 +33 16 49.6 303.550976 13.489014 n.a. n.a. 0.985679742652 -0.2485989 0.00099932644747 0.1835413 60.7425 /T 119.2068 66.9/ 0.3837 n.a. n.a. 61.783085 128.06292 13.811407 2024-Nov-30 20:20 18 16 36.51 +33 10 27.9 304.885133 12.019212 n.a. n.a. 0.985678754919 -0.2439429 0.00100003975559 0.1720741 60.7135 /T 119.2358 66.8/ 0.3754 n.a. n.a. 62.508181 127.39620 12.823852 2024-Nov-30 20:30 18 17 16.35 +33 04 07.5 306.238157 10.572862 n.a. n.a. 0.985677785870 -0.2392824 0.00100070618919 0.1601681 60.6866 /T 119.2626 66.8/ 0.3672 n.a. n.a. 63.221016 126.73822 11.823871 2024-Nov-30 20:40 18 17 56.93 +32 57 48.7 307.611061 9.151009 n.a. n.a. 0.985676835522 -0.2346172 0.00100132399735 0.1478279 60.6621 /T 119.2872 66.7/ 0.3592 n.a. n.a. 63.920840 126.08943 10.811863 2024-Nov-30 20:50 18 18 38.25 +32 51 31.5 309.004824 7.754730 n.a. n.a. 0.985675903894 -0.2299470 0.00100189144895 0.1350588 60.6398 /T 119.3095 66.7/ 0.3512 n.a. n.a. 64.606908 125.45022 9.7882499 2024-Nov-30 21:00 18 19 20.29 +32 45 16.2 310.420385 6.385139 n.a. n.a. 0.985674991009 -0.2252715 0.00100240683548 0.1218668 60.6198 /T 119.3294 66.6/ 0.3433 n.a. n.a. 65.278474 124.82091 8.7534718 2024-Nov-30 21:10 18 20 03.04 +32 39 02.9 311.858637 5.043384 n.a. n.a. 0.985674096887 -0.2205902 0.00100286847365 0.1082585 60.6022 /T 119.3470 66.6/ 0.3356 n.a. n.a. 65.934802 124.20183 7.7079868 2024-Nov-30 21:20 18 20 46.47 +32 32 51.8 313.320429 3.730648 n.a. n.a. 0.985673221552 -0.2159028 0.00100327470800 0.0942411 60.5871 /T 119.3621 66.5/ 0.3281 n.a. n.a. 66.575162 123.59323 6.6522691 2024-Nov-30 21:30 18 21 30.58 +32 26 43.0 314.806557 2.448150 n.a. n.a. 0.985672365031 -0.2112090 0.00100362391349 0.0798226 60.5743 /T 119.3749 66.5/ 0.3206 n.a. n.a. 67.198830 122.99534 5.5868069 2024-Nov-30 21:40 18 22 15.35 +32 20 36.7 316.317760 1.197142 n.a. n.a. 0.985671527348 -0.2065084 0.00100391449788 0.0650114 60.5640 /T 119.3851 66.5/ 0.3134 n.a. n.a. 67.805097 122.40839 4.5121013 2024-Nov-30 21:50 18 23 00.75 +32 14 32.9 317.854710 -0.021089 n.a. n.a. 0.985670708532 -0.2018007 0.00100414490418 0.0498165 60.5562 /T 119.3929 66.4/ 0.3062 n.a. n.a. 68.393265 121.83253 3.4286643 >..... 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 ***************************************************************************************************************************************************************************************************************************************************