API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: Oct 07, 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-Oct-02 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_25092 2010-Feb-25 2025-Apr-02 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Thu Nov 7 14:20:44 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: iTelescope Obs.,Beryl Junc. (Sato) ******************************************************************************* 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 : 246.3025, 37.7377919, 1.56349 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 246.3025,5051.53114,3883.42609 {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.241106.p250201 EOP coverage : DATA-BASED 1962-JAN-20 TO 2024-NOV-06. PREDICTS-> 2025-JAN-31 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 >..... Daylight Cut-off Requested .....< 2024-Oct-31 00:50 Ce 20 01 52.92 +19 15 40.6 173.685176 71.502527 n.a. n.a. 0.992819946727 0.1046136 0.00054275153539 -1.7859607 90.1097 /T 89.8586 104.5/ 2.1701 n.a. n.a. 119.92226 148.93236 -66.22550 2024-Oct-31 01:00 Ct 20 02 36.95 +18 58 13.3 180.599349 71.303524 n.a. n.a. 0.992820366305 0.1045910 0.00053556422498 -1.7978435 90.1971 /T 89.7716 104.5/ 2.1503 n.a. n.a. 123.94855 149.23102 -65.94822 2024-Oct-31 01:10 N 20 03 22.03 +18 40 07.2 187.305798 70.875843 n.a. n.a. 0.992820785535 0.1044383 0.00052832819921 -1.8102571 90.2864 /T 89.6828 104.6/ 2.1303 n.a. n.a. 128.20735 149.48735 -65.66339 2024-Oct-31 01:20 N 20 04 08.26 +18 21 20.7 193.676443 70.233154 n.a. n.a. 0.992821203875 0.1041453 0.00052104123454 -1.8232489 90.3777 /T 89.5918 104.7/ 2.1101 n.a. n.a. 132.71212 149.70324 -65.37181 2024-Oct-31 01:30 N 20 04 55.77 +18 01 51.9 199.622990 69.394528 n.a. n.a. 0.992821620739 0.1037003 0.00051370091471 -1.8368675 90.4716 /T 89.4984 104.8/ 2.0898 n.a. n.a. 137.47792 149.88076 -65.07419 2024-Oct-31 01:40 A 20 05 44.67 +17 41 38.7 205.098690 68.381836 n.a. n.a. 0.992822035492 0.1030906 0.00050630462436 -1.8511635 90.5684 /T 89.4020 104.9/ 2.0692 n.a. n.a. 142.52157 150.02209 -64.77122 2024-Oct-31 01:50 A 20 06 35.10 +17 20 38.9 210.092161 67.217472 n.a. n.a. 0.992822447446 0.1023022 0.00049884954208 -1.8661891 90.6686 /T 89.3023 105.0/ 2.0484 n.a. n.a. 147.86192 150.12950 -64.46352 2024-Oct-31 02:00 A 20 07 27.19 +16 58 50.3 214.617634 65.922716 n.a. n.a. 0.992822855855 0.1013197 0.00049133263333 -1.8819984 90.7724 /T 89.1989 105.0/ 2.0275 n.a. n.a. 153.52009 150.20537 -64.15163 2024-Oct-31 02:10 20 08 21.10 +16 36 10.2 218.705181 64.516809 n.a. n.a. 0.992823259905 0.1001257 0.00048375064252 -1.8986476 90.8803 /T 89.0914 105.1/ 2.0064 n.a. n.a. 159.51975 150.25212 -63.83606 2024-Oct-31 02:20 20 09 16.96 +16 12 35.9 222.392820 63.016562 n.a. n.a. 0.992823658711 0.0987013 0.00047610008480 -1.9161948 90.9929 /T 88.9792 105.2/ 1.9851 n.a. n.a. 165.88750 150.27226 -63.51722 2024-Oct-31 02:30 20 10 14.94 +15 48 04.5 225.720990 61.436333 n.a. n.a. 0.992824051307 0.0970250 0.00046837723709 -1.9347007 91.1107 /T 88.8619 105.3/ 1.9637 n.a. n.a. 172.65326 150.26829 -63.19548 2024-Oct-31 02:40 20 11 15.23 +15 22 32.6 228.729103 59.788212 n.a. n.a. 0.992824436634 0.0950731 0.00046057812838 -1.9542283 91.2340 /T 88.7391 105.5/ 1.9422 n.a. n.a. 179.85076 150.24280 -62.87110 2024-Oct-31 02:50 20 12 17.99 +14 55 56.7 231.453662 58.082285 n.a. n.a. 0.992824813537 0.0928190 0.00045269852903 -1.9748434 91.3635 /T 88.6100 105.6/ 1.9205 n.a. n.a. 187.51806 150.19836 -62.54429 2024-Oct-31 03:00 20 13 23.42 +14 28 12.9 233.927392 56.326927 n.a. n.a. 0.992825180743 0.0902326 0.00044473393937 -1.9966150 91.4998 /T 88.4742 105.7/ 1.8987 n.a. n.a. 195.69828 150.13756 -62.21516 2024-Oct-31 03:10 20 14 31.75 +13 59 16.8 236.179014 54.529067 n.a. n.a. 0.992825536854 0.0872803 0.00043667957685 -2.0196153 91.6434 /T 88.3310 105.8/ 1.8768 n.a. n.a. 204.44036 150.06304 -61.88371 2024-Oct-31 03:20 20 15 43.19 +13 29 03.7 238.233361 52.694436 n.a. n.a. 0.992825880327 0.0839240 0.00042853036208 -2.0439201 91.7950 /T 88.1799 106.0/ 1.8549 n.a. n.a. 213.80001 149.97739 -61.54987 2024-Oct-31 03:30 20 16 57.98 +12 57 28.2 240.111672 50.827762 n.a. n.a. 0.992826209458 0.0801205 0.00042028090329 -2.0696094 91.9554 /T 88.0200 106.1/ 1.8328 n.a. n.a. 223.84088 149.88325 -61.21343 2024-Oct-31 03:40 20 18 16.40 +12 24 24.5 241.831943 48.932945 n.a. n.a. 0.992826522355 0.0758206 0.00041192547923 -2.0967675 92.1251 /T 87.8507 106.3/ 1.8107 n.a. n.a. 234.63592 149.78322 -60.87407 2024-Oct-31 03:50 20 19 38.73 +11 49 45.9 243.409289 47.013184 n.a. n.a. 0.992826816919 0.0709683 0.00040345802001 -2.1254840 92.3051 /T 87.6713 106.4/ 1.7885 n.a. n.a. 246.26912 149.67995 -60.53133 2024-Oct-31 04:00 20 21 05.28 +11 13 25.1 244.856277 45.071089 n.a. n.a. 0.992827090808 0.0654993 0.00039487208600 -2.1558538 92.4961 /T 87.4808 106.6/ 1.7663 n.a. n.a. 258.83752 149.57604 -60.18461 2024-Oct-31 04:10 20 22 36.40 +10 35 13.7 246.183214 43.108764 n.a. n.a. 0.992827341403 0.0593394 0.00038616084408 -2.1879783 92.6990 /T 87.2783 106.8/ 1.7440 n.a. n.a. 272.45381 149.47412 -59.83313 2024-Oct-31 04:20 20 24 12.48 +09 55 02.3 247.398387 41.127871 n.a. n.a. 0.992827565765 0.0524032 0.00037731704149 -2.2219655 92.9148 /T 87.0630 107.0/ 1.7217 n.a. n.a. 287.24946 149.37684 -59.47591 2024-Oct-31 04:30 20 25 53.94 +09 12 40.3 248.508260 39.129679 n.a. n.a. 0.992827760588 0.0445912 0.00036833297652 -2.2579313 93.1445 /T 86.8339 107.2/ 1.6995 n.a. n.a. 303.37870 149.28682 -59.11177 2024-Oct-31 04:40 20 27 41.25 +08 27 55.3 249.517610 37.115096 n.a. n.a. 0.992827922131 0.0357871 0.00035920046611 -2.2960000 93.3892 /T 86.5897 107.4/ 1.6772 n.a. n.a. 321.02347 149.20673 -58.73926 2024-Oct-31 04:50 20 29 34.94 +07 40 33.4 250.429624 35.084687 n.a. n.a. 0.992828046149 0.0258545 0.00034991080988 -2.3363053 93.6500 /T 86.3294 107.7/ 1.6549 n.a. n.a. 340.39973 149.13925 -58.35665 2024-Oct-31 05:00 20 31 35.61 +06 50 18.6 251.245945 33.038689 n.a. n.a. 0.992828127802 0.0146323 0.00034045475071 -2.3789912 93.9284 /T 86.0516 107.9/ 1.6327 n.a. n.a. 361.76551 149.08708 -57.96187 2024-Oct-31 05:10 20 33 43.95 +05 56 52.0 251.966667 30.977002 n.a. n.a. 0.992828161544 0.0019287 0.00033082243171 -2.4242129 94.2255 /T 85.7550 108.2/ 1.6106 n.a. n.a. 385.43134 149.05296 -57.55243 2024-Oct-31 05:20 20 36 00.75 +04 59 51.8 252.590274 28.899176 n.a. n.a. 0.992828140988 -0.0124857 0.00032100334981 -2.4721376 94.5430 /T 85.4381 108.5/ 1.5885 n.a. n.a. 411.77385 149.03969 -57.12537 2024-Oct-31 05:30 20 38 26.91 +03 58 52.5 253.113520 26.804384 n.a. n.a. 0.992828058734 -0.0288879 0.00031098630700 -2.5229445 94.8823 /T 85.0993 108.8/ 1.5664 n.a. n.a. 441.25361 149.05010 -56.67716 2024-Oct-31 05:40 20 41 03.49 +02 53 23.7 253.531235 24.691375 n.a. n.a. 0.992827906157 -0.0476145 0.00030075936076 -2.5768255 95.2453 /T 84.7369 109.1/ 1.5445 n.a. n.a. 474.43907 149.08712 -56.20355 2024-Oct-31 05:50 20 43 51.74 +01 42 49.3 253.836032 22.558413 n.a. n.a. 0.992827673135 -0.0690788 0.00029030977650 -2.6339835 95.6336 /T 84.3492 109.5/ 1.5226 n.a. n.a. 512.03880 149.15369 -55.69941 2024-Oct-31 06:00 20 46 53.16 +00 26 25.9 254.017897 20.403196 n.a. n.a. 0.992827347697 -0.0937932 0.00027962398740 -2.6946298 96.0492 /T 83.9342 109.9/ 1.5008 n.a. n.a. 554.94555 149.25287 -55.15853 2024-Oct-31 06:10 20 50 09.54 -00 56 39.2 254.063620 18.222732 n.a. n.a. 0.992826915571 -0.1223991 0.00026868757091 -2.7589784 96.4939 /T 83.4902 110.3/ 1.4792 n.a. n.a. 604.29766 149.38775 -54.57333 2024-Oct-31 06:20 20 53 43.08 -02 27 30.7 253.955998 16.013187 n.a. n.a. 0.992826359583 -0.1557100 0.00025748525727 -2.8272355 96.9696 /T 83.0151 110.7/ 1.4577 n.a. n.a. 661.56551 149.56145 -53.93445 2024-Oct-31 06:30 20 57 36.50 -04 07 28.6 253.672717 13.769677 n.a. n.a. 0.992825658858 -0.1947704 0.00024600099637 -2.8995799 97.4778 /T 82.5075 111.2/ 1.4363 n.a. n.a. 728.67576 149.77704 -53.23023 2024-Oct-31 06:40 21 01 53.22 -05 58 13.8 253.184789 11.485976 n.a. n.a. 0.992824787729 -0.2409412 0.00023421812935 -2.9761289 98.0198 /T 81.9662 111.6/ 1.4151 n.a. n.a. 808.19309 150.03740 -52.44598 2024-Oct-31 06:50 21 06 37.67 -08 01 54.5 252.454291 9.154131 n.a. n.a. 0.992823714240 -0.2960244 0.00022211974323 -3.0568790 98.5955 /T 81.3912 112.1/ 1.3940 n.a. n.a. 903.59137 150.34497 -51.56289 2024-Oct-31 07:00 21 11 55.66 -10 21 16.9 251.431080 6.763927 n.a. n.a. 0.992822398022 -0.3624487 0.00020968935004 -3.1415990 99.2032 /T 80.7842 112.6/ 1.3731 n.a. n.a. 1019.6671 150.70123 -50.55655 2024-Oct-31 07:10 21 17 55.05 -12 59 59.6 250.047882 4.302157 n.a. n.a. 0.992820787258 -0.4435529 0.00019691214242 -3.2296407 99.8376 /T 80.1505 113.1/ 1.3524 n.a. n.a. 1163.1841 151.10568 -49.39465 2024-Oct-31 07:20 21 24 46.83 -16 02 56.4 248.212797 1.751617 n.a. n.a. 0.992818814214 -0.5440281 0.00018377729445 -3.3195908 100.4871 /T 79.5018 113.5/ 1.3319 n.a. n.a. 1343.9015 151.55391 -48.03357 >..... Elevation Cut-off Requested .....< 2024-Oct-31 11:00 14 02 56.93 +32 28 38.4 47.347918 -0.056144 n.a. n.a. 0.992566621285 -2.1912512 0.00024182355062 3.2063522 46.9586 /L 133.0318 45.2/ 0.9438 n.a. n.a. 824.32153 58.496629 53.073393 2024-Oct-31 11:10 14 11 52.49 +33 35 02.2 46.753365 0.909685 n.a. n.a. 0.992558028283 -2.0955351 0.00025451439244 3.1228802 47.8932 /L 132.0965 46.7/ 0.9295 n.a. n.a. 743.06026 60.118383 53.793206 2024-Oct-31 11:20 14 20 10.54 +34 32 18.8 46.351911 1.851283 n.a. n.a. 0.992549799171 -2.0095142 0.00026687728309 3.0428002 48.7788 /L 131.2102 48.0/ 0.9155 n.a. n.a. 674.61259 61.607864 54.425316 2024-Oct-31 11:30 14 27 55.24 +35 22 06.3 46.111296 2.777675 n.a. n.a. 0.992541898162 -1.9316990 0.00027892583886 2.9661011 49.6175 /T 130.3708 49.2/ 0.9018 n.a. n.a. 616.29109 62.977868 54.985491 2024-Oct-31 11:40 14 35 10.12 +36 05 41.6 46.005799 3.696066 n.a. n.a. 0.992534294833 -1.8608918 0.00029067343801 2.8926842 50.4119 /T 129.5758 50.4/ 0.8884 n.a. n.a. 566.08444 64.239755 55.486254 2024-Oct-31 11:50 14 41 58.18 +36 44 05.4 46.014616 4.612260 n.a. n.a. 0.992526963093 -1.7961194 0.00030213296467 2.8224069 51.1649 /T 128.8220 51.4/ 0.8752 n.a. n.a. 522.46287 65.403634 55.937694 2024-Oct-31 12:00 14 48 21.99 +37 18 06.4 46.120702 5.530970 n.a. n.a. 0.992519880394 -1.7365831 0.00031331668545 2.7551068 51.8797 /T 128.1066 52.4/ 0.8624 n.a. n.a. 484.24578 66.478537 56.348052 2024-Oct-31 12:10 14 54 23.77 +37 48 24.0 46.309936 6.456040 n.a. n.a. 0.992513027102 -1.6816213 0.00032423620314 2.6906168 52.5588 /T 127.4269 53.4/ 0.8500 n.a. n.a. 450.50989 67.472567 56.724139 2024-Oct-31 12:20 15 00 05.46 +38 15 30.3 46.570494 7.390625 n.a. n.a. 0.992506386009 -1.6306814 0.00033490245454 2.6287728 53.2049 /T 126.7801 54.2/ 0.8378 n.a. n.a. 420.52436 68.393019 57.071653 2024-Oct-31 12:30 15 05 28.76 +38 39 51.8 46.892383 8.337314 n.a. n.a. 0.992499941946 -1.5832985 0.00034532573312 2.5694185 53.8205 /T 126.1639 55.1/ 0.8258 n.a. n.a. 393.70433 69.246503 57.395410 2024-Oct-31 12:40 A 15 10 35.13 +39 01 50.4 47.267091 9.298236 n.a. n.a. 0.992493681457 -1.5390778 0.00035551572461 2.5124072 54.4076 /T 125.5762 55.8/ 0.8142 n.a. n.a. 369.57704 70.039028 57.699516 2024-Oct-31 12:50 A 15 15 25.91 +39 21 44.5 47.687308 10.275140 n.a. n.a. 0.992487592554 -1.4976827 0.00036548154872 2.4576032 54.9682 /T 125.0150 56.6/ 0.8029 n.a. n.a. 347.75677 70.776089 57.987508 2024-Oct-31 13:00 A 15 20 02.25 +39 39 49.5 48.146716 11.269453 n.a. n.a. 0.992481664498 -1.4588238 0.00037523180264 2.4048817 55.5042 /T 124.4785 57.3/ 0.7919 n.a. n.a. 327.92621 71.462739 58.262455 2024-Oct-31 13:10 Nm 15 24 25.18 +39 56 18.4 48.639819 12.282336 n.a. n.a. 0.992475887632 -1.4222508 0.00038477460402 2.3541281 56.0170 /T 123.9651 57.9/ 0.7811 n.a. n.a. 309.82226 72.103647 58.527041 2024-Oct-31 13:20 Nm 15 28 35.65 +40 11 22.3 49.161810 13.314723 n.a. n.a. 0.992470253232 -1.3877467 0.00039411763206 2.3052382 56.5081 /T 123.4734 58.6/ 0.7707 n.a. n.a. 293.22519 72.703152 58.783628 2024-Oct-31 13:30 Nm 15 32 34.48 +40 25 10.8 49.708462 14.367351 n.a. n.a. 0.992464753390 -1.3551214 0.00040326816596 2.2581166 56.9789 /T 123.0021 59.2/ 0.7605 n.a. n.a. 277.95032 73.265310 59.034306 2024-Oct-31 13:40 Cm 15 36 22.42 +40 37 51.8 50.276041 15.440794 n.a. n.a. 0.992459380913 -1.3242084 0.00041223312039 2.2126767 57.4304 /T 122.5500 59.8/ 0.7506 n.a. n.a. 263.84146 73.793936 59.280936 2024-Oct-31 13:50 Cm 15 40 00.14 +40 49 32.4 50.861233 16.535482 n.a. n.a. 0.992454129233 -1.2948610 0.00042101907799 2.1688393 57.8637 /T 122.1162 60.3/ 0.7409 n.a. n.a. 250.76576 74.292639 59.525178 >..... Daylight 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 ***************************************************************************************************************************************************************************************************************************************************