API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: May 14, 2026 NISAR Spacecraft / (Earth) -165053 https://science.nasa.gov/mission/nisar/ https://www.isro.gov.in/NISARSatellite.html BACKGROUND: The NASA-ISRO Synthetic Aperture RADAR (NISAR) mission will measure Earth's surface every twelve days durings its 3-year baseline mission. This will provide information about changing biomass, natural hazards, sea level and groundwater. NISAR launched July 30, 2025 @ 12:10 UTC from Satish Dhawan Space Centre on a GSLV F16 launch vehicle. The first 90 days after launch are dedicated to commissioning; an in-orbit activation and check of systems to prepare for science operations. Extensive calibration and validation activities will take place throughout the first 5 months, with yearly updates of 1-month duration. SPACECRAFT PHYSICAL CHARACTERISTICS: * Bus : ISRO I-3K (a.k.a. INSAT 3000) * Total mass : 2393 kg * Solar panels : 6500 Watts * Consumables : 5 years * SAR : dual frequency polarimetric radar L-band (24-cm, NASA) S-band (12-cm, ISRO) 242 km imaging swath * SAR resolution : 3-10 m (mode dependent) * Antenna/reflector : 12 m diameter GENERAL ORBIT Altitude : 747 km (~circular orbit) Inclination : 98.4 degrees Orbit period : 100 minutes Nodal crossing: 6 a.m. / 6 p.m. Orbit control : 500 m SPACECRAFT TRAJECTORY: Concatenated historical TLEs from Space-Track with SGP4 extrapolation 30 days into the future. Name Start (TDB) Stop (TDB) ------------------------------------------------------ ----------- ----------- NISAR (Concatenated TLEs) 2025-Jul-30 latest+30d ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Thu May 14 06:41:26 2026 Pasadena, USA / Horizons ******************************************************************************* Target body name: NISAR (spacecraft) (-165053) {source: NISAR} Center body name: Earth (399) {source: DE441} Center-site name: Swan Reach Imaging, Glenalta ******************************************************************************* Start time : A.D. 2025-Aug-07 00:00:00.0000 UT Stop time : A.D. 2025-Aug-21 00:00:00.0000 UT Step-size : 10 minutes ******************************************************************************* Target pole/equ : undefined Target radii : undefined Center geodetic : 139.5701, -34.5440227, .056888 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 139.5701,5259.32258,-3596.34777 {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.260513.p260809 EOP coverage : DATA-BASED 1962-JAN-20 TO 2026-MAY-13. PREDICTS-> 2026-AUG-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 .....< >..... Daylight Cut-off Requested .....< 2025-Aug-07 08:10 Cr 15 58 51.83 +34 04 26.5 18.929813 18.478181 n.a. n.a. 1.014062744223 0.7494669 0.00001156897244 -6.4126219 90.7988 /T 89.1993 78.7/ 95.7207 n.a. n.a. 28731.979 189.73554 -57.93097 2025-Aug-07 08:20 Ct 04 02 30.81 -57 27 03.4 190.685608 3.465624 n.a. n.a. 1.014065211864 0.4224154 0.00001887451616 6.7583899 96.7950 /L 83.2053 85.6/ 95.7454 n.a. n.a. 14768.869 348.42607 63.501463 >..... Elevation Cut-off Requested .....< 2025-Aug-07 09:50 r 11 34 51.56 +18 37 29.2 297.019883 5.601703 n.a. n.a. 1.014052253393 0.7415083 0.00001738551432 -2.7755359 34.7735 /T 145.2251 125.0/ 95.9464 n.a. n.a. 33162.955 206.27853 -21.71548 >..... Elevation Cut-off Requested .....< 2025-Aug-07 20:20 Ar 08 36 36.50 -40 02 17.0 124.089159 22.655547 n.a. n.a. 1.013988440224 -0.9151765 0.00001048081391 -4.0507762 56.8665 /L 123.1320 115.1/ 97.2247 n.a. n.a. 49884.763 308.10262 -32.65431 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-08 09:10 Ar 09 35 27.73 -37 00 28.1 238.025929 19.954819 n.a. n.a. 1.013903803488 0.5848243 0.00001117994278 3.8715747 53.3950 /T 126.6054 118.8/ 99.0102 n.a. n.a. 47582.248 230.50236 31.053974 >..... Elevation Cut-off Requested .....< 2025-Aug-08 19:40 r 06 32 36.35 +19 18 16.2 60.645795 7.128113 n.a. n.a. 1.013835492556 -1.0965591 0.00001660852024 2.9320900 38.6161 /L 141.3841 147.9/ 99.5791 n.a. n.a. 34372.855 333.50567 23.022392 >..... Elevation Cut-off Requested .....< 2025-Aug-08 21:10 Cr 14 30 09.67 -58 07 47.9 171.287207 3.840372 n.a. n.a. 1.013828053023 -0.6429409 0.00001869926941 -6.7264540 97.8043 /T 82.1933 75.9/ 99.6657 n.a. n.a. 15225.970 182.18698 -62.90271 2025-Aug-08 21:20 Ct 01 55 22.96 +32 38 05.4 335.523549 17.749490 n.a. n.a. 1.013824462218 -1.1061643 0.00001190485336 6.3667819 97.2506 /L 82.7499 89.3/ 99.6752 n.a. n.a. 28370.900 354.15332 57.329595 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-09 08:20 Cr 15 30 03.58 +34 15 14.5 8.930795 20.636705 n.a. n.a. 1.013750244434 0.6657915 0.00001089565383 -6.3212259 83.8913 /T 96.1069 98.7/ 99.9457 n.a. n.a. 31518.118 196.25383 -56.70876 2025-Aug-09 08:30 Ct 04 39 15.24 -55 30 39.6 193.763341 2.463808 n.a. n.a. 1.013752408583 0.3591876 0.00001954283664 6.7536397 91.8596 /L 88.1406 85.5/ 99.9440 n.a. n.a. 14170.287 333.65268 63.635639 >..... Elevation Cut-off Requested .....< 2025-Aug-09 10:00 r 11 34 19.25 +16 15 03.8 292.408290 3.625379 n.a. n.a. 1.013739371523 0.6580244 0.00001861052195 -2.4259661 33.0267 /T 146.9720 149.7/ 99.9258 n.a. n.a. 31520.105 206.23604 -18.88768 >..... Elevation Cut-off Requested .....< 2025-Aug-09 20:30 Ar 08 32 48.68 -44 49 41.3 127.079309 28.288053 n.a. n.a. 1.013672928955 -0.8805047 0.00000916961020 -4.2142733 61.4057 /L 118.5929 117.9/ 99.7098 n.a. n.a. 56157.952 307.02900 -34.09579 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-10 09:20 Ar 09 38 26.76 -33 50 23.5 239.307928 15.745737 n.a. n.a. 1.013585696156 0.5077187 0.00001259832980 3.6979327 49.5667 /T 130.4338 133.2/ 98.4341 n.a. n.a. 42805.302 229.75601 29.568112 >..... Elevation Cut-off Requested .....< 2025-Aug-10 19:50 r 06 27 57.27 +22 04 39.9 55.005631 9.202509 n.a. n.a. 1.013515074578 -1.0439493 0.00001551057442 3.3625809 41.6190 /L 138.3813 119.8/ 97.4092 n.a. n.a. 35783.058 333.34322 26.622083 >..... Elevation Cut-off Requested .....< 2025-Aug-10 21:20 Cr 15 13 42.48 -59 39 41.3 174.847536 4.685151 n.a. n.a. 1.013507146935 -0.6280128 0.00001817632922 -6.6388655 102.1738 /T 77.8239 92.5/ 97.2067 n.a. n.a. 16541.452 165.99891 -61.30118 >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-11 08:30 Ct 14 57 23.74 +33 26 46.4 357.727896 22.068048 n.a. n.a. 1.013427375201 0.5802129 0.00001048580314 -6.0738541 76.2065 /T 103.7917 119.9/ 94.6842 n.a. n.a. 35471.487 201.84378 -53.49151 2025-Aug-11 08:40 Ne 05 11 53.94 -53 29 05.3 196.498199 1.391670 n.a. n.a. 1.013429229826 0.2949914 0.00002028909166 6.7022226 87.2036 /L 92.7965 86.1/ 94.6436 n.a. n.a. 13934.572 320.64011 62.984005 >..... Elevation Cut-off Requested .....< 2025-Aug-11 10:10 r 11 35 43.81 +14 08 11.4 288.319584 1.709406 n.a. n.a. 1.013416139915 0.5726263 0.00001989690394 -2.1256247 31.7685 /T 148.2303 169.2/ 94.2933 n.a. n.a. 29846.983 206.27362 -16.49479 >..... Elevation Cut-off Requested .....< 2025-Aug-11 19:00 r 08 34 15.87 -18 58 25.4 113.371166 -0.020201 n.a. n.a. 1.013358676754 -0.8305452 0.00002136320159 -1.9826138 36.3748 /L 143.6238 133.0/ 92.7395 n.a. n.a. 27669.470 316.68641 -15.50328 >..... Elevation Cut-off Requested .....< 2025-Aug-11 20:40 Nr 08 18 58.51 -50 54 29.4 131.967087 35.216577 n.a. n.a. 1.013347156550 -0.8437842 0.00000796621321 -4.3248040 67.6235 /L 112.3751 113.4/ 92.4203 n.a. n.a. 63976.689 306.50803 -35.06565 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-12 09:30 Ar 09 43 51.99 -31 19 45.5 240.049071 12.189232 n.a. n.a. 1.013257365516 0.4286172 0.00001404700933 3.5263378 46.4305 /T 133.5699 136.2/ 88.1611 n.a. n.a. 38868.585 229.20155 28.118575 >..... Elevation Cut-off Requested .....< 2025-Aug-12 20:00 Ar 06 19 53.60 +25 07 59.8 48.534886 11.228624 n.a. n.a. 1.013184399059 -0.9894107 0.00001453470467 3.8455062 45.5284 /L 134.4720 89.4/ 85.4007 n.a. n.a. 36721.705 333.09301 30.797920 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-13 08:40 Nt 14 23 59.88 +31 31 15.2 345.860444 22.486822 n.a. n.a. 1.013094123579 0.4917602 0.00001036884949 -5.6561731 68.1563 /T 111.8420 134.4/ 80.2684 n.a. n.a. 39911.241 205.48797 -48.51169 2025-Aug-13 08:50 Ne 05 41 07.76 -51 27 36.8 198.899442 0.272684 n.a. n.a. 1.013095658811 0.2288746 0.00002110179422 6.6128544 82.8246 /L 97.1755 86.0/ 80.1878 n.a. n.a. 13941.421 309.61151 61.731715 >..... Elevation Cut-off Requested .....< 2025-Aug-13 10:20 r 11 38 42.75 +12 15 14.1 284.663386 -0.136447 n.a. n.a. 1.013082502346 0.4843374 0.00002122922589 -1.8699069 30.9036 /T 149.0953 153.2/ 79.4847 n.a. n.a. 28217.436 206.37687 -14.47979 >..... Elevation Cut-off Requested .....< 2025-Aug-13 19:10 r 08 43 05.60 -19 34 55.1 112.588841 2.066301 n.a. n.a. 1.013022691705 -0.7943135 0.00001987828877 -2.0854879 36.2672 /L 143.7314 116.5/ 76.5133 n.a. n.a. 29661.886 316.86987 -16.30507 >..... Elevation Cut-off Requested .....< 2025-Aug-13 20:50 Nr 07 43 52.15 -58 12 56.3 140.385495 43.567742 n.a. n.a. 1.013010791993 -0.8061102 0.00000693616431 -4.3081620 76.1216 /L 103.8772 104.2/ 76.0503 n.a. n.a. 73758.169 308.87182 -34.85920 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-14 09:40 r 09 50 51.98 -29 18 51.6 240.413999 9.118634 n.a. n.a. 1.012918142065 0.3465524 0.00001551292069 3.3600468 43.8038 /T 136.1966 125.3/ 69.9247 n.a. n.a. 35583.457 228.82014 26.730753 >..... Elevation Cut-off Requested .....< 2025-Aug-14 20:10 Ar 06 07 43.94 +28 24 01.7 41.148787 13.099764 n.a. n.a. 1.012842527468 -0.9340235 0.00001371320909 4.3687650 50.4040 /L 129.5964 57.8/ 65.6739 n.a. n.a. 36903.060 332.79384 35.534557 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-15 08:50 Nt 13 53 17.34 +28 38 18.3 334.109450 21.803465 n.a. n.a. 1.012749239184 0.3995404 0.00001055219169 -5.0951420 60.2834 /T 119.7150 131.1/ 59.5696 n.a. n.a. 43621.074 207.29657 -42.48274 >..... Elevation Cut-off Requested .....< 2025-Aug-15 19:20 r 08 51 11.37 -20 17 08.9 111.815210 4.351377 n.a. n.a. 1.012674659795 -0.7580187 0.00001838104089 -2.1822037 36.2939 /L 143.7048 96.7/ 54.5278 n.a. n.a. 31998.851 317.05969 -17.05830 >..... Elevation Cut-off Requested .....< 2025-Aug-15 21:00 Cr 06 21 37.28 -65 05 21.2 155.786047 52.537361 n.a. n.a. 1.012662312201 -0.7683518 0.00000617790791 -4.0372034 87.3577 /L 92.6411 95.9/ 54.0197 n.a. n.a. 85373.172 320.83052 -32.33965 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-16 09:50 r 09 58 57.22 -27 40 32.4 240.508262 6.417446 n.a. n.a. 1.012566245740 0.2608993 0.00001698644688 3.1994150 41.5607 /T 138.4396 106.8/ 47.6372 n.a. n.a. 32812.395 228.57823 25.404535 >..... Elevation Cut-off Requested .....< 2025-Aug-16 20:10 Ar 12 21 53.60 -47 38 31.1 153.432190 0.398649 n.a. n.a. 1.012490460085 -0.5686749 0.00002112804121 -6.1494119 70.5241 /T 109.4735 133.3/ 42.6917 n.a. n.a. 16589.065 258.25114 -55.43322 2025-Aug-16 20:20 Ae 05 50 53.48 +31 43 12.7 32.845406 14.668076 n.a. n.a. 1.012487501331 -0.8784429 0.00001308050057 4.9073213 56.2232 /L 123.7773 25.5/ 42.6416 n.a. n.a. 36062.562 332.56685 40.716575 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-17 09:00 Nr 13 27 38.62 +25 11 14.5 323.209195 20.180273 n.a. n.a. 1.012390586729 0.3031785 0.00001101814205 -4.4524830 53.0984 /T 126.9001 112.0/ 37.0374 n.a. n.a. 45664.997 207.97416 -36.20856 >..... Elevation Cut-off Requested .....< 2025-Aug-17 19:30 r 08 58 21.10 -21 06 41.9 111.053804 6.886788 n.a. n.a. 1.012312337826 -0.7219810 0.00001687478358 -2.2715885 36.4947 /L 143.5040 76.4/ 31.7801 n.a. n.a. 34773.333 317.25482 -17.75334 >..... Elevation Cut-off Requested .....< 2025-Aug-17 21:10 Ct 03 59 50.38 -65 54 48.7 182.794808 58.638360 n.a. n.a. 1.012299459703 -0.7308312 0.00000581080773 -3.3817465 100.9241 /L 79.0749 95.5/ 31.2965 n.a. n.a. 96186.923 347.08256 -26.58540 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-18 08:20 Ct 10 49 11.41 -80 04 17.2 191.556696 37.483961 n.a. n.a. 1.012212239768 0.1818702 0.00000756907395 5.3935010 93.4770 /T 86.5236 116.5/ 26.9869 n.a. n.a. 57914.792 258.01915 45.509755 >..... Elevation Cut-off Requested .....< 2025-Aug-18 10:00 r 10 07 49.76 -26 19 32.3 240.402757 4.002897 n.a. n.a. 1.012199337094 0.1716177 0.00001846046241 3.0436697 39.6137 /T 140.3866 85.6/ 26.0504 n.a. n.a. 30451.971 228.44394 24.130642 >..... Elevation Cut-off Requested .....< 2025-Aug-18 20:20 Ar 12 45 15.05 -49 52 55.4 155.406165 1.790748 n.a. n.a. 1.012119770335 -0.5559571 0.00002014505981 -6.3195496 73.3696 /T 106.6281 118.4/ 21.4878 n.a. n.a. 16442.261 251.50992 -57.64182 2025-Aug-18 20:30 Ne 05 29 09.18 +34 50 29.3 23.748367 15.759506 n.a. n.a. 1.012116955477 -0.8227511 0.00001266996043 5.4241005 62.8556 /L 117.1449 9.245/ 21.4435 n.a. n.a. 34090.653 332.68684 46.092684 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-19 09:10 Ar 13 07 52.83 +21 35 04.3 313.587742 17.935212 n.a. n.a. 1.012015812776 0.2029460 0.00001172900011 -3.7971109 46.9293 /T 133.0692 87.0/ 17.3500 n.a. n.a. 45865.075 208.15105 -30.28301 >..... Elevation Cut-off Requested .....< 2025-Aug-19 19:40 r 09 04 15.38 -22 05 07.3 110.297041 9.746371 n.a. n.a. 1.011933421628 -0.6859638 0.00001536308704 -2.3505215 36.9212 /L 143.0776 57.7/ 13.1793 n.a. n.a. 38117.138 317.46485 -18.36468 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2025-Aug-20 08:30 Ct 09 51 01.95 -70 01 13.8 203.837865 32.843968 n.a. n.a. 1.011828768157 0.0887120 0.00000826134650 5.5770697 82.4621 /L 97.5385 99.6/ 10.0840 n.a. n.a. 50954.798 262.92990 47.625458 >..... Elevation Cut-off Requested .....< 2025-Aug-20 10:10 r 10 17 16.18 -25 12 20.1 240.137630 1.813318 n.a. n.a. 1.011815230251 0.0792786 0.00001993042688 2.8925574 37.9067 /T 142.0936 64.2/ 9.4966 n.a. n.a. 28420.411 228.39759 22.904706 >..... Elevation Cut-off Requested .....< 2025-Aug-20 20:30 Nr 13 11 00.74 -52 18 13.8 157.732467 3.202043 n.a. n.a. 1.011731496546 -0.5433269 0.00001919977871 -6.4677396 76.5370 /T 103.4607 101.6/ 6.4791 n.a. n.a. 16314.508 243.00768 -59.65349 2025-Aug-20 20:40 Ne 05 03 04.39 +37 27 09.7 14.141788 16.216066 n.a. n.a. 1.011728826862 -0.7664507 0.00001250883701 5.8758226 70.0492 /L 109.9513 40.9/ 6.4495 n.a. n.a. 31186.606 333.63270 51.251408 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< $$EOE *************************************************************************************************************************************************************************************************************************************************** Column meaning: TIME Times PRIOR to 1962 are UT1, a mean-solar time closely related to the prior but now-deprecated GMT. Times AFTER 1962 are in UTC, the current civil or "wall-clock" time-scale. UTC is kept within 0.9 seconds of UT1 using integer leap-seconds for 1972 and later years. Conversion from the internal Barycentric Dynamical Time (TDB) of solar system dynamics to the non-uniform civil UT time-scale requested for output has not been determined for UTC times after the next July or January 1st. Therefore, the last known leap-second is used as a constant over future intervals. Time tags refer to the UT time-scale conversion from TDB on Earth regardless of observer location within the solar system, although clock rates may differ due to the local gravity field and no analog to "UT" may be defined for that location. Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank (" ") denotes an A.D. date. CALENDAR SYSTEM Mixed calendar mode was active such that calendar dates after AD 1582-Oct-15 (if any) are in the modern Gregorian system. Dates prior to 1582-Oct-5 (if any) are in the Julian calendar system, which is automatically extended for dates prior to its adoption on 45-Jan-1 BC. The Julian calendar is useful for matching historical dates. The Gregorian calendar more accurately corresponds to the Earth's orbital motion and seasons. A "Gregorian-only" calendar mode is available if such physical events are the primary interest. NOTE: "n.a." in output means quantity "not available" at the print-time. SOLAR PRESENCE (OBSERVING SITE) Time tag is followed by a blank, then a solar-presence condition code: '*' Daylight (refracted solar upper-limb on or above apparent horizon) 'C' Civil twilight/dawn 'N' Nautical twilight/dawn 'A' Astronomical twilight/dawn ' ' Night OR geocentric ephemeris LUNAR PRESENCE WITH TARGET RISE/TRANSIT/SET EVENT MARKER (OBSERVING SITE) The solar-presence code column is immediately followed by another marker: 'm' Refracted upper-limb of Moon on or above apparent horizon ' ' Refracted upper-limb of Moon below apparent horizon OR geocentric The lunar presence marker (an ongoing state) can be over-ridden by a target event marker if an event has occurred since the last output step: 'r' Rise (target body on or went above cut-off RTS elevation) 'e' Elevation max (target body maximum elevation angle has occurred) 't' Transit (target body at or passed through observer meridian) 's' Set (target body on or went below cut-off RTS elevation) RTS MARKERS (TVH) Rise and set are with respect to the reference ellipsoid true visual horizon defined by the elevation cut-off angle. Horizon dip and yellow-light refraction (Earth only) are considered. Accuracy is < or = to twice the requested search step-size. 'R.A._____(ICRF)_____DEC' = Astrometric right ascension and declination of the target center with respect to the observing site (coordinate origin) in the reference frame of the planetary ephemeris (ICRF). Compensated for down-leg light-time delay aberration. Units: RA in hours-minutes-seconds of time, HH MM SS.ff{ffff} DEC in degrees-minutes-seconds of arc, sDD MN SC.f{ffff} 'Azi____(a-app)___Elev' = Airless apparent azimuth and elevation of target center. Compensated for light-time, the gravitational deflection of light, stellar aberration, precession and nutation. Azimuth is measured clockwise from north: North(0) -> East(90) -> South(180) -> West(270) -> North (360) Elevation angle is with respect to a plane perpendicular to the reference surface local zenith direction. TOPOCENTRIC ONLY. Units: DEGREES 'APmag S-brt' = The targets' approximate apparent visual magnitude and surface brightness. For planets and natural satellites, output is restricted to solar phase angles covered by observational data. Outside the observed phase angle range, "n.a." may be output to avoid extrapolation beyond the limit of model validity. For Earth-based observers, the estimated dimming due to atmospheric absorption (extinction) is available as a separate, requestable quantity. Surface brightness is the average airless visual magnitude of a square-arcsecond of the illuminated portion of the apparent disk. It is computed only if the target radius is known. Units: MAGNITUDES & MAGNITUDES PER SQUARE ARCSECOND 'r rdot' = The Sun's apparent range ("r", light-time aberrated) and range-rate ("rdot") relative to the target center, as seen by the observer. A positive "rdot" means the target center was moving away from the Sun, negative means moving toward the Sun. Units: AU and KM/S 'delta deldot' = Apparent range ("delta", light-time aberrated) and range-rate ("delta-dot") of the target center relative to the observer. A positive "deldot" means the target center is moving away from the observer, negative indicates movement toward the observer. Units: AU and KM/S 'S-O-T /r' = Sun-Observer-Target apparent SOLAR ELONGATION ANGLE seen from the observers' location at print-time. The '/r' column provides a code indicating the targets' apparent position relative to the Sun in the observers' sky, as described below: Case A: For an observing location on the surface of a rotating body, that body rotational sense is considered: /T indicates target TRAILS Sun (evening sky: rises and sets AFTER Sun) /L indicates target LEADS Sun (morning sky: rises and sets BEFORE Sun) Case B: For an observing point that does not have a rotational model (such as a spacecraft), the "leading" and "trailing" condition is defined by the observers' heliocentric ORBITAL motion: * If continuing in the observers' current direction of heliocentric motion would encounter the targets' apparent longitude first, followed by the Sun's, the target LEADS the Sun as seen by the observer. * If the Sun's apparent longitude would be encountered first, followed by the targets', the target TRAILS the Sun. Two other codes can be output: /* indicates observer is Sun-centered (undefined) /? Target is aligned with Sun center (no lead or trail) The S-O-T solar elongation angle is numerically the minimum separation angle of the Sun and target in the sky in any direction. It does NOT indicate the amount of separation in the leading or trailing directions, which would be defined along the equator of a spherical coordinate system. Units: DEGREES 'S-T-O' = The Sun-Target-Observer angle; the interior vertex angle at target center formed by a vector from the target to the apparent center of the Sun (at reflection time on the target) and the apparent vector from target to the observer at print-time. Slightly different from true PHASE ANGLE (requestable separately) at the few arcsecond level in that it includes stellar aberration on the down-leg from target to observer. Units: DEGREES 'T-O-M/MN_Illu%' = Target-Observer-Moon LUNAR ELONGATION angle and illuminated percentage. The apparent lunar elongation angle between target body center and Moon center, seen from the observing site, along with fraction of the lunar disk illuminated by the Sun. A negative lunar elongation angle indicates the target center is behind the Moon. Units: DEGREES & PERCENT 'RA_3sigma DEC_3sigma' = Uncertainty in Right-Ascension and Declination. Output values are the formal +/- 3 standard-deviations (sigmas) around nominal position. Units: ARCSECONDS 'Sky_motion Sky_mot_PA RelVel-ANG' = Total apparent angular rate of the target in the plane-of-sky. "Sky_mot_PA" is the position angle of the target's direction of motion in the plane-of-sky, measured counter-clockwise from the apparent of-date north pole direction. "RelVel-ANG" is the flight path angle of the target's relative motion with respect to the observer's line-of-sight, in the range [-90,+90], where positive values indicate motion away from the observer, negative values are toward the observer: -90 = target is moving directly toward the observer 0 = target is moving at right angles to the observer's line-of-sight +90 = target is moving directly away from the observer UNITS: ARCSECONDS/MINUTE, DEGREES, DEGREES Computations by ... Solar System Dynamics Group, Horizons On-Line Ephemeris System 4800 Oak Grove Drive, Jet Propulsion Laboratory Pasadena, CA 91109 USA General site: https://ssd.jpl.nasa.gov/ Mailing list: https://ssd.jpl.nasa.gov/email_list.html System news : https://ssd.jpl.nasa.gov/horizons/news.html User Guide : https://ssd.jpl.nasa.gov/horizons/manual.html Connect : browser https://ssd.jpl.nasa.gov/horizons/app.html#/x API https://ssd-api.jpl.nasa.gov/doc/horizons.html command-line telnet ssd.jpl.nasa.gov 6775 e-mail/batch https://ssd.jpl.nasa.gov/ftp/ssd/horizons_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov ***************************************************************************************************************************************************************************************************************************************************