API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: Aug 26, 2026 Spektr-R Telescope (Spacecraft) -557 (Earth orbiting) http://www.spaceflightnow.com/news/n1107/18spektr/ BACKGROUND: Russian Earth-orbiting radio telescope funded by Russian Astro Space Center. It was launched from the Baikonur Cosmodrome on July 18, 2011 at 02:31 UTC by a Zenit-3M launcher with Fregat-SB upper stage. MISSION OBJECTIVES: The primary scientific goal of Spektr-R over the planned 5-year mission is the study of astronomical objects at an angular resolution of a few millionths of an arcsecond. This is accomplished by using the satellite interferometrically in conjunction with ground-based observatories, including Arecibo and Greenbank. The primary targets are extragalactic. Characteristics of near-Earth and interplanetary plasma will also be studied. Wavelengths used are 1.35-6.0, 18.0 and 92.0 cm. PHYSICAL DATA: Mass : 3295 kg Diameter: 10 m SPACECRAFT TRAJECTORY: Perigee: ~ 10,000 km Apogee : ~390,000 km TRAJECTORY: The IKI (Russian Space Research Institute) provided an official trajectory for Nov 1-16 (2011). TLEs are used for other times, and are low-precision, especially during the following intervals which are extrapolations over data gaps: 2011: 2012: 2013: Jul 22 - Aug 04 Feb 26 - Apr 24 Jan 16 - Jun 02 Aug 12 - Oct 04 May 11 - May 29 Jul 04 - Jul 14 Dec 09 - Feb 17 (2012) Jun 12 - Aug 30 Oct 16 - Nov 02 Sep 08 - Jan 08 (2013) Dec 24 - Jan 10 Jan 19 - Feb 22 May 09 - May 27 Trajectory name Start Stop ------------------------------ ----------------- ----------------- TLEs 2011-Jun-18 06:09 2011-Nov-01 11:01 spectr_111101_111116_111102 2011-Nov-01 11:01 2011-Nov-16 01:07 TLEs 2011-Nov-16 01:07 Current ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Wed Sep 16 11:14:10 2026 Pasadena, USA / Horizons ******************************************************************************* Target body name: Spektr-R Observatory (spacecraft) (-557) {source: spektr-r_MERGED} Center body name: Earth (399) {source: DE441} Center-site name: Swan Reach Imaging, Glenalta ******************************************************************************* Start time : A.D. 2026-Sep-02 00:00:00.0000 UT Stop time : A.D. 2026-Sep-05 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.260915.p261212 EOP coverage : DATA-BASED 1962-JAN-20 TO 2026-SEP-15. PREDICTS-> 2026-DEC-11 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 .....< 2026-Sep-02 17:10 r 07 30 04.80 -06 01 51.6 97.223716 0.243873 n.a. n.a. 1.008199791391 -1.6967507 0.00115418024550 1.0775657 50.7163 /L 129.2330 71.9/ 67.5792 n.a. n.a. 37.594598 81.684073 64.044969 2026-Sep-02 17:20 m 07 30 29.16 -06 00 56.2 95.852021 2.203561 n.a. n.a. 1.008192989224 -1.6917763 0.00115850412801 1.0697087 50.6204 /L 129.3288 72.0/ 67.5285 n.a. n.a. 36.151497 81.393594 64.672710 2026-Sep-02 17:30 m 07 30 52.54 -06 00 01.0 94.483181 4.171476 n.a. n.a. 1.008186206913 -1.6868396 0.00116279786140 1.0625643 50.5283 /L 129.4208 72.0/ 67.4784 n.a. n.a. 34.726461 81.074847 65.327021 2026-Sep-02 17:40 m 07 31 14.98 -05 59 06.1 93.114003 6.146443 n.a. n.a. 1.008179444308 -1.6819400 0.00116706431029 1.0561354 50.4401 /L 129.5089 72.0/ 67.4289 n.a. n.a. 33.321112 80.725277 66.006313 2026-Sep-02 17:50 m 07 31 36.46 -05 58 11.3 91.741231 8.127281 n.a. n.a. 1.008172701261 -1.6770768 0.00117130634876 1.0504237 50.3557 /L 129.5932 72.0/ 67.3799 n.a. n.a. 31.937105 80.342066 66.708715 2026-Sep-02 18:00 m 07 31 57.01 -05 57 16.7 90.361523 10.112796 n.a. n.a. 1.008165977627 -1.6722496 0.00117552685543 1.0454298 50.2750 /L 129.6737 72.1/ 67.3313 n.a. n.a. 30.576120 79.922116 67.432074 2026-Sep-02 18:10 m 07 32 16.65 -05 56 22.2 88.971421 12.101771 n.a. n.a. 1.008159273262 -1.6674578 0.00117972870853 1.0411530 50.1979 /L 129.7506 72.1/ 67.2831 n.a. n.a. 29.239860 79.462015 68.173955 2026-Sep-02 18:20 m 07 32 35.39 -05 55 27.7 87.567326 14.092955 n.a. n.a. 1.008152588027 -1.6627008 0.00118391478077 1.0375913 50.1245 /L 129.8239 72.1/ 67.2354 n.a. n.a. 27.930050 78.958020 68.931654 2026-Sep-02 18:30 m 07 32 53.24 -05 54 33.2 86.145463 16.085048 n.a. n.a. 1.008145921782 -1.6579781 0.00118808793424 1.0347413 50.0546 /L 129.8937 72.1/ 67.1879 n.a. n.a. 26.648437 78.406030 69.702208 2026-Sep-02 18:40 m 07 33 10.22 -05 53 38.6 84.701850 18.076694 n.a. n.a. 1.008139274391 -1.6532892 0.00119225101519 1.0325984 49.9882 /L 129.9600 72.1/ 67.1407 n.a. n.a. 25.396783 77.801566 70.482419 2026-Sep-02 18:50 m 07 33 26.35 -05 52 44.0 83.232260 20.066458 n.a. n.a. 1.008132645720 -1.6486336 0.00119640684884 1.0311569 49.9251 /L 130.0229 72.1/ 67.0938 n.a. n.a. 24.176870 77.139756 71.268881 2026-Sep-02 19:00 m 07 33 41.65 -05 51 49.2 81.732178 22.052821 n.a. n.a. 1.008126035635 -1.6440108 0.00120055823405 1.0304094 49.8654 /L 130.0826 72.1/ 67.0470 n.a. n.a. 22.990488 76.415333 72.058009 2026-Sep-02 19:10 m 07 33 56.15 -05 50 54.2 80.196758 24.034152 n.a. n.a. 1.008119444007 -1.6394204 0.00120470793804 1.0303474 49.8088 /L 130.1390 72.1/ 67.0004 n.a. n.a. 21.839441 75.622637 72.846076 2026-Sep-02 19:20 m 07 34 09.85 -05 49 59.0 78.620773 26.008695 n.a. n.a. 1.008112870706 -1.6348617 0.00120885869115 1.0309610 49.7554 /L 130.1923 72.1/ 66.9538 n.a. n.a. 20.725540 74.755643 73.629256 2026-Sep-02 19:30 m 07 34 22.80 -05 49 03.5 76.998560 27.974542 n.a. n.a. 1.008106315607 -1.6303345 0.00121301318151 1.0322391 49.7050 /L 130.2425 72.1/ 66.9073 n.a. n.a. 19.650596 73.808020 74.403669 2026-Sep-02 19:40 Am 07 34 35.00 -05 48 07.8 75.323963 29.929611 n.a. n.a. 1.008099778585 -1.6258381 0.00121717404976 1.0341692 49.6576 /L 130.2898 72.1/ 66.8608 n.a. n.a. 18.616418 72.773220 75.165422 2026-Sep-02 19:50 Am 07 34 46.48 -05 47 11.7 73.590267 31.871612 n.a. n.a. 1.008093259515 -1.6213723 0.00122134388388 1.0367375 49.6130 /L 130.3343 72.1/ 66.8142 n.a. n.a. 17.624802 71.644617 75.910662 2026-Sep-02 20:00 Am 07 34 57.27 -05 46 15.3 71.790132 33.798015 n.a. n.a. 1.008086758278 -1.6169364 0.00122552521400 1.0399290 49.5711 /L 130.3760 72.0/ 66.7674 n.a. n.a. 16.677521 70.415719 76.635625 2026-Sep-02 20:10 Nm 07 35 07.39 -05 45 18.4 69.915522 35.706011 n.a. n.a. 1.008080274753 -1.6125302 0.00122972050733 1.0437273 49.5318 /L 130.4151 72.0/ 66.7206 n.a. n.a. 15.776308 69.080451 77.336686 2026-Sep-02 20:20 Nm 07 35 16.88 -05 44 21.2 67.957638 37.592467 n.a. n.a. 1.008073808823 -1.6081532 0.00123393216314 1.0481149 49.4951 /L 130.4517 72.0/ 66.6735 n.a. n.a. 14.922834 67.633533 78.010404 2026-Sep-02 20:30 Nm 07 35 25.75 -05 43 23.5 65.906844 39.453875 n.a. n.a. 1.008067360372 -1.6038049 0.00123816250788 1.0530731 49.4608 /L 130.4858 72.0/ 66.6261 n.a. n.a. 14.118685 66.070974 78.653582 2026-Sep-02 20:40 Cm 07 35 34.03 -05 42 25.3 63.752616 41.286290 n.a. n.a. 1.008060929284 -1.5994850 0.00124241379036 1.0585819 49.4288 /L 130.5177 71.9/ 66.5785 n.a. n.a. 13.365319 64.390672 79.263310 2026-Sep-02 20:50 Cm 07 35 41.76 -05 41 26.7 61.483499 43.085274 n.a. n.a. 1.008054515448 -1.5951931 0.00124668817717 1.0646202 49.3990 /L 130.5473 71.9/ 66.5305 n.a. n.a. 12.664027 62.593123 79.837022 >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2026-Sep-03 17:50 r 08 06 41.81 -03 41 01.6 94.260948 0.439638 n.a. n.a. 1.007357563968 -1.1958398 0.00179001502736 0.4100634 42.1009 /L 137.8308 66.4/ 56.2932 n.a. n.a. 16.149717 79.272383 49.562287 2026-Sep-03 18:00 m 08 06 52.14 -03 40 30.7 92.859932 2.460251 n.a. n.a. 1.007352764551 -1.1933877 0.00179166238711 0.4067478 42.0627 /L 137.8690 66.4/ 56.2388 n.a. n.a. 15.363129 78.727767 50.714996 2026-Sep-03 18:10 m 08 07 01.94 -03 39 59.8 91.459095 4.485184 n.a. n.a. 1.007347974961 -1.1909429 0.00179329781175 0.4041389 42.0266 /L 137.9051 66.3/ 56.1851 n.a. n.a. 14.581080 78.118368 51.969817 2026-Sep-03 18:20 m 08 07 11.20 -03 39 28.9 90.054917 6.513214 n.a. n.a. 1.007343195169 -1.1885053 0.00179492413864 0.4022379 41.9927 /L 137.9390 66.3/ 56.1321 n.a. n.a. 13.805199 77.435035 53.325383 2026-Sep-03 18:30 m 08 07 19.94 -03 38 58.0 88.643816 8.543099 n.a. n.a. 1.007338425147 -1.1860749 0.00179654420679 0.4010446 41.9609 /L 137.9708 66.3/ 56.0797 n.a. n.a. 13.037169 76.666944 54.778453 2026-Sep-03 18:40 m 08 07 28.15 -03 38 27.1 87.222113 10.573578 n.a. n.a. 1.007333664867 -1.1836517 0.00179816085156 0.4005573 41.9312 /L 138.0005 66.3/ 56.0278 n.a. n.a. 12.278744 75.801239 56.323622 2026-Sep-03 18:50 m 08 07 35.84 -03 37 56.2 85.786008 12.603350 n.a. n.a. 1.007328914299 -1.1812355 0.00179977689936 0.4007732 41.9035 /L 138.0281 66.2/ 55.9764 n.a. n.a. 11.531758 74.822588 57.953081 2026-Sep-03 19:00 m 08 07 43.02 -03 37 25.1 84.331543 14.631065 n.a. n.a. 1.007324173416 -1.1788262 0.00180139516220 0.4016881 41.8779 /L 138.0537 66.2/ 55.9256 n.a. n.a. 10.798145 73.712632 59.656444 2026-Sep-03 19:10 m 08 07 49.69 -03 36 54.0 82.854569 16.655308 n.a. n.a. 1.007319442190 -1.1764240 0.00180301843232 0.4032962 41.8543 /L 138.0773 66.2/ 55.8751 n.a. n.a. 10.079963 72.449307 61.420664 2026-Sep-03 19:20 m 08 07 55.86 -03 36 22.8 81.350709 18.674586 n.a. n.a. 1.007314720594 -1.1740286 0.00180464947677 0.4055906 41.8327 /L 138.0988 66.1/ 55.8250 n.a. n.a. 9.3794215 71.006034 63.230081 2026-Sep-03 19:30 m 08 08 01.54 -03 35 51.4 79.815319 20.687306 n.a. n.a. 1.007310008600 -1.1716400 0.00180629103191 0.4085631 41.8131 /L 138.1184 66.1/ 55.7752 n.a. n.a. 8.6989236 69.350742 65.066582 2026-Sep-03 19:40 Am 08 08 06.74 -03 35 20.0 78.243445 22.691763 n.a. n.a. 1.007305306181 -1.1692582 0.00180794579812 0.4122040 41.7954 /L 138.1361 66.1/ 55.7257 n.a. n.a. 8.0411183 67.444775 66.909895 2026-Sep-03 19:50 Am 08 08 11.46 -03 34 48.3 76.629773 24.686114 n.a. n.a. 1.007300613311 -1.1668832 0.00180961643431 0.4165022 41.7796 /L 138.1519 66.0/ 55.6763 n.a. n.a. 7.4089649 65.241728 68.737980 2026-Sep-03 20:00 Am 08 08 15.73 -03 34 16.5 74.968588 26.668354 n.a. n.a. 1.007295929962 -1.1645148 0.00181130555261 0.4214454 41.7656 /L 138.1658 66.0/ 55.6272 n.a. n.a. 6.8058135 62.686425 70.527483 2026-Sep-03 20:10 Nm 08 08 19.55 -03 33 44.4 73.253716 28.636292 n.a. n.a. 1.007291256108 -1.1621530 0.00181301571303 0.4270200 41.7533 /L 138.1780 65.9/ 55.5781 n.a. n.a. 6.2354989 59.714425 72.254209 2026-Sep-03 20:20 Nm 08 08 22.93 -03 33 12.2 71.478469 30.587520 n.a. n.a. 1.007286591724 -1.1597977 0.00181474941831 0.4332111 41.7429 /L 138.1885 65.9/ 55.5291 n.a. n.a. 5.7024380 56.252860 73.893602 2026-Sep-03 20:30 Nm 08 08 25.89 -03 32 39.7 69.635597 32.519376 n.a. n.a. 1.007281936783 -1.1574490 0.00181650910869 0.4400024 41.7340 /L 138.1972 65.8/ 55.4800 n.a. n.a. 5.2117091 52.223952 75.421226 2026-Sep-03 20:40 Cm 08 08 28.44 -03 32 07.0 67.717226 34.428909 n.a. n.a. 1.007277291258 -1.1551067 0.00181829715685 0.4473765 41.7268 /L 138.2044 65.8/ 55.4309 n.a. n.a. 4.7690626 47.553272 76.813347 2026-Sep-03 20:50 Cm 08 08 30.60 -03 31 34.0 65.714812 36.312831 n.a. n.a. 1.007272655126 -1.1527709 0.00182011586299 0.4553147 41.7212 /L 138.2099 65.7/ 55.3817 n.a. n.a. 4.3807780 42.185200 78.047810 >..... Daylight Cut-off Requested .....< >..... Elevation Cut-off Requested .....< 2026-Sep-04 18:10 r 08 27 16.38 -02 11 39.7 92.561112 0.301217 n.a. n.a. 1.006749503148 -0.8928047 0.00213624212144 0.0377908 37.5496 /L 142.3763 57.2/ 44.6688 n.a. n.a. 11.495300 76.922632 7.2517417 2026-Sep-04 18:20 m 08 27 23.64 -02 11 12.4 91.151997 2.335739 n.a. n.a. 1.006745920138 -0.8909960 0.00213639215565 0.0356175 37.5239 /L 142.4020 57.1/ 44.6118 n.a. n.a. 10.863375 76.139927 7.2320080 2026-Sep-04 18:30 m 08 27 30.48 -02 10 45.1 89.741251 4.372758 n.a. n.a. 1.006742344396 -0.8891897 0.00213653486653 0.0341553 37.5000 /L 142.4259 57.1/ 44.5556 n.a. n.a. 10.234805 75.255957 7.3592697 2026-Sep-04 18:40 m 08 27 36.88 -02 10 17.8 88.325272 6.411025 n.a. n.a. 1.006738775912 -0.8873859 0.00213667310742 0.0334046 37.4778 /L 142.4482 57.0/ 44.5003 n.a. n.a. 9.6112111 74.253599 7.6606674 2026-Sep-04 18:50 m 08 27 42.85 -02 09 50.5 86.900392 8.449275 n.a. n.a. 1.006735214676 -0.8855846 0.00213680972995 0.0333642 37.4574 /L 142.4686 57.0/ 44.4457 n.a. n.a. 8.9943220 73.111935 8.1692300 2026-Sep-04 19:00 m 08 27 48.40 -02 09 23.1 85.462846 10.486207 n.a. n.a. 1.006731660680 -0.8837856 0.00213694757855 0.0340317 37.4386 /L 142.4874 57.0/ 44.3918 n.a. n.a. 8.3860043 71.805250 8.9250962 2026-Sep-04 19:10 m 08 27 53.51 -02 08 55.6 84.008742 12.520477 n.a. n.a. 1.006728113912 -0.8819890 0.00213708948510 0.0354032 37.4216 /L 142.5044 56.9/ 44.3387 n.a. n.a. 7.7883004 70.301737 9.9767547 2026-Sep-04 19:20 m 08 27 58.21 -02 08 28.1 82.534031 14.550680 n.a. n.a. 1.006724574364 -0.8801947 0.00213723826342 0.0374736 37.4063 /L 142.5198 56.9/ 44.2861 n.a. n.a. 7.2034812 68.561846 11.382004 2026-Sep-04 19:30 m 08 28 02.49 -02 08 00.6 81.034469 16.575339 n.a. n.a. 1.006721042027 -0.8784028 0.00213739670382 0.0402364 37.3926 /L 142.5335 56.8/ 44.2341 n.a. n.a. 6.6341178 66.536209 13.207973 2026-Sep-04 19:40 Am 08 28 06.36 -02 07 32.9 79.505585 18.592887 n.a. n.a. 1.006717516890 -0.8766133 0.00213756756767 0.0436835 37.3806 /L 142.5455 56.8/ 44.1826 n.a. n.a. 6.0831800 64.163125 15.528942 2026-Sep-04 19:50 Am 08 28 09.83 -02 07 05.1 77.942637 20.601646 n.a. n.a. 1.006713998944 -0.8748260 0.00213775358192 0.0478058 37.3702 /L 142.5559 56.7/ 44.1316 n.a. n.a. 5.5541679 61.365725 18.419729 2026-Sep-04 20:00 Am 08 28 12.90 -02 06 37.3 76.340577 22.599814 n.a. n.a. 1.006710488181 -0.8730411 0.00213795743370 0.0525927 37.3614 /L 142.5647 56.7/ 44.0811 n.a. n.a. 5.0512855 58.049290 21.941405 2026-Sep-04 20:10 Nm 08 28 15.58 -02 06 09.3 74.694005 24.585437 n.a. n.a. 1.006706984590 -0.8712584 0.00213818176493 0.0580322 37.3541 /L 142.5720 56.6/ 44.0308 n.a. n.a. 4.5796570 54.099939 26.115965 2026-Sep-04 20:20 Nm 08 28 17.88 -02 05 41.2 72.997125 26.556386 n.a. n.a. 1.006703488163 -0.8694780 0.00213842916703 0.0641110 37.3484 /L 142.5777 56.6/ 43.9810 n.a. n.a. 4.1455653 49.387380 30.889973 2026-Sep-04 20:30 Nm 08 28 19.81 -02 05 13.0 71.243699 28.510330 n.a. n.a. 1.006699998891 -0.8676999 0.00213870217554 0.0708147 37.3442 /L 142.5820 56.5/ 43.9313 n.a. n.a. 3.7566452 43.776846 36.097240 2026-Sep-04 20:40 Cm 08 28 21.38 -02 04 44.6 69.427001 30.444706 n.a. n.a. 1.006696516764 -0.8659239 0.00213900326510 0.0781273 37.3414 /L 142.5848 56.5/ 43.8819 n.a. n.a. 3.4218636 37.157998 41.445315 2026-Sep-04 20:50 Cm 08 28 22.61 -02 04 16.1 67.539773 32.356679 n.a. n.a. 1.006693041774 -0.8641502 0.00213933484423 0.0860318 37.3399 /L 142.5862 56.4/ 43.8326 n.a. n.a. 3.1509808 29.497711 46.554964 >..... 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/horizons_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Inquiries : Jon.D.Giorgini@jpl.nasa.gov ***************************************************************************************************************************************************************************************************************************************************