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 02:30:11 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: El Berrueco ******************************************************************************* 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 : 356.4134, 40.8833094, 1.06361 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 356.4134,4829.88693,4153.33056 {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 04:10 17 28 43.84 +38 28 56.6 34.319261 -0.211250 n.a. n.a. 0.985864092835 -0.7311915 0.00086540702456 0.7007010 61.9485 /T 118.0073 67.7/ 1.1668 n.a. n.a. 81.406847 93.486619 39.444665 2024-Nov-30 04:20 17 29 52.35 +38 28 06.3 35.774297 0.742155 n.a. n.a. 0.985861172505 -0.7250703 0.00086817899901 0.6816206 61.9993 /T 117.9563 67.8/ 1.1524 n.a. n.a. 79.817761 93.306530 39.133149 2024-Nov-30 04:30 17 30 59.51 +38 27 19.5 37.209870 1.733412 n.a. n.a. 0.985858276633 -0.7189945 0.00087087512801 0.6628814 62.0508 /T 117.9046 67.9/ 1.1383 n.a. n.a. 78.223592 93.134079 38.830438 2024-Nov-30 04:40 17 32 05.31 +38 26 35.8 38.625845 2.761543 n.a. n.a. 0.985855405040 -0.7129630 0.00087349680204 0.6444945 62.1029 /T 117.8524 68.0/ 1.1246 n.a. n.a. 76.624802 92.970152 38.537299 2024-Nov-30 04:50 17 33 09.76 +38 25 55.2 40.022172 3.825564 n.a. n.a. 0.985852557551 -0.7069746 0.00087604545616 0.6264708 62.1553 /T 117.7998 68.1/ 1.1111 n.a. n.a. 75.021918 92.815702 38.254549 2024-Nov-30 05:00 17 34 12.83 +38 25 17.4 41.398882 4.924493 n.a. n.a. 0.985849733996 -0.7010284 0.00087852256895 0.6088212 62.2080 /T 117.7469 68.2/ 1.0980 n.a. n.a. 73.415528 92.671761 37.983046 2024-Nov-30 05:10 17 35 14.54 +38 24 42.1 42.756077 6.057345 n.a. n.a. 0.985846934206 -0.6951231 0.00088092966121 0.5915558 62.2609 /T 117.6939 68.3/ 1.0853 n.a. n.a. 71.806287 92.539446 37.723698 2024-Nov-30 05:20 17 36 14.88 +38 24 09.2 44.093934 7.223146 n.a. n.a. 0.985844158020 -0.6892580 0.00088326829462 0.5746849 62.3139 /T 117.6408 68.4/ 1.0728 n.a. n.a. 70.194912 92.419970 37.477464 2024-Nov-30 05:30 17 37 13.85 +38 23 38.3 45.412693 8.420924 n.a. n.a. 0.985841405278 -0.6834318 0.00088554007030 0.5582180 62.3667 /T 117.5878 68.4/ 1.0607 n.a. n.a. 68.582188 92.314646 37.245355 2024-Nov-30 05:40 17 38 11.44 +38 23 09.4 46.712653 9.649722 n.a. n.a. 0.985838675827 -0.6776438 0.00088774662720 0.5421643 62.4194 /T 117.5350 68.5/ 1.0489 n.a. n.a. 66.968968 92.224904 37.028434 2024-Nov-30 05:50 A 17 39 07.66 +38 22 42.0 47.994175 10.908593 n.a. n.a. 0.985835969516 -0.6718928 0.00088988964042 0.5265326 62.4717 /T 117.4826 68.6/ 1.0374 n.a. n.a. 65.356176 92.152297 36.827820 2024-Nov-30 06:00 A 17 40 02.51 +38 22 16.1 49.257667 12.196604 n.a. n.a. 0.985833286197 -0.6661782 0.00089197081939 0.5113313 62.5235 /T 117.4306 68.7/ 1.0262 n.a. n.a. 63.744808 92.098519 36.644689 2024-Nov-30 06:10 A 17 40 55.99 +38 21 51.3 50.503590 13.512836 n.a. n.a. 0.985830625727 -0.6604989 0.00089399190598 0.4965681 62.5748 /T 117.3792 68.8/ 1.0153 n.a. n.a. 62.135934 92.065410 36.480269 2024-Nov-30 06:20 N 17 41 48.09 +38 21 27.3 51.732451 14.856390 n.a. n.a. 0.985827987965 -0.6548540 0.00089595467249 0.4822505 62.6254 /T 117.3285 68.9/ 1.0047 n.a. n.a. 60.530702 92.054981 36.335846 2024-Nov-30 06:30 N 17 42 38.83 +38 21 04.0 52.944799 16.226381 n.a. n.a. 0.985825372776 -0.6492428 0.00089786091949 0.4683852 62.6752 /T 117.2785 68.9/ 0.9944 n.a. n.a. 58.930341 92.069419 36.212758 2024-Nov-30 06:40 Nm 17 43 28.21 +38 20 41.0 54.141224 17.621944 n.a. n.a. 0.985822780025 -0.6436644 0.00089971247361 0.4549783 62.7241 /T 117.2295 69.0/ 0.9844 n.a. n.a. 57.336164 92.111111 36.112391 2024-Nov-30 06:50 Cm 17 44 16.23 +38 20 18.0 55.322358 19.042230 n.a. n.a. 0.985820209584 -0.6381181 0.00090151118525 0.4420356 62.7720 /T 117.1815 69.1/ 0.9746 n.a. n.a. 55.749575 92.182659 36.036176 2024-Nov-30 07:00 Cm 17 45 02.90 +38 19 54.9 56.488869 20.486411 n.a. n.a. 0.985817661324 -0.6326029 0.00090325892611 0.4295620 62.8187 /T 117.1346 69.2/ 0.9651 n.a. n.a. 54.172068 92.286898 35.985577 2024-Nov-30 07:10 Cm 17 45 48.23 +38 19 31.3 57.641466 21.953677 n.a. n.a. 0.985815135123 -0.6271182 0.00090495758670 0.4175619 62.8643 /T 117.0890 69.2/ 0.9559 n.a. n.a. 52.605240 92.426915 35.962087 >..... Daylight Cut-off Requested .....< 2024-Nov-30 17:00 C 18 06 36.00 +35 32 22.5 278.659719 51.181497 n.a. n.a. 0.985702044944 -0.3366779 0.00097610255023 0.3006019 61.8916 /T 118.0583 68.5/ 0.5536 n.a. n.a. 43.306724 145.58708 30.464534 2024-Nov-30 17:10 C 18 06 56.31 +35 26 22.3 279.749555 49.334193 n.a. n.a. 0.985700703912 -0.3320416 0.00097730539725 0.2991388 61.8306 /T 118.1193 68.4/ 0.5454 n.a. n.a. 44.164471 144.93635 29.824394 2024-Nov-30 17:20 N 18 07 17.35 +35 20 18.0 280.825970 47.493585 n.a. n.a. 0.985699381470 -0.3274073 0.00097850166617 0.2973193 61.7698 /T 118.1801 68.4/ 0.5371 n.a. n.a. 45.024001 144.26206 29.171152 2024-Nov-30 17:30 N 18 07 39.12 +35 14 09.9 281.892317 45.660260 n.a. n.a. 0.985698077613 -0.3227745 0.00097968990034 0.2951299 61.7094 /T 118.2405 68.3/ 0.5288 n.a. n.a. 45.884923 143.56723 28.504219 2024-Nov-30 17:40 N 18 08 01.66 +35 07 58.1 282.951508 43.834804 n.a. n.a. 0.985696792334 -0.3181431 0.00098086859009 0.2925578 61.6495 /T 118.3003 68.2/ 0.5204 n.a. n.a. 46.746839 142.85471 27.823066 2024-Nov-30 17:50 N 18 08 24.96 +35 01 43.0 284.006096 42.017798 n.a. n.a. 0.985695525628 -0.3135126 0.00098203617582 0.2895908 61.5902 /T 118.3596 68.1/ 0.5120 n.a. n.a. 47.609339 142.12713 27.127229 2024-Nov-30 18:00 A 18 08 49.07 +34 55 24.8 285.058350 40.209831 n.a. n.a. 0.985694277493 -0.3088827 0.00098319105108 0.2862178 61.5316 /T 118.4182 68.0/ 0.5035 n.a. n.a. 48.471998 141.38697 26.416312 2024-Nov-30 18:10 A 18 09 13.97 +34 49 03.8 286.110311 38.411493 n.a. n.a. 0.985693047926 -0.3042530 0.00098433156579 0.2824282 61.4738 /T 118.4759 68.0/ 0.4950 n.a. n.a. 49.334369 140.63651 25.689980 2024-Nov-30 18:20 A 18 09 39.70 +34 42 40.2 287.163831 36.623386 n.a. n.a. 0.985691836928 -0.2996233 0.00098545602948 0.2782123 61.4170 /T 118.5327 67.9/ 0.4864 n.a. n.a. 50.195983 139.87789 24.947965 2024-Nov-30 18:30 18 10 06.26 +34 36 14.3 288.220608 34.846121 n.a. n.a. 0.985690644499 -0.2949933 0.00098656271456 0.2735614 61.3612 /T 118.5885 67.8/ 0.4779 n.a. n.a. 51.056345 139.11309 24.190059 2024-Nov-30 18:40 18 10 33.65 +34 29 46.3 289.282221 33.080323 n.a. n.a. 0.985689470641 -0.2903625 0.00098764985967 0.2684673 61.3065 /T 118.6432 67.7/ 0.4693 n.a. n.a. 51.914937 138.34395 23.416117 2024-Nov-30 18:50 18 11 01.89 +34 23 16.5 290.350143 31.326629 n.a. n.a. 0.985688315358 -0.2857307 0.00098871567301 0.2629231 61.2530 /T 118.6966 67.6/ 0.4607 n.a. n.a. 52.771208 137.57215 22.626051 2024-Nov-30 19:00 18 11 30.99 +34 16 45.2 291.425765 29.585695 n.a. n.a. 0.985687178655 -0.2810975 0.00098975833574 0.2569222 61.2009 /T 118.7487 67.6/ 0.4520 n.a. n.a. 53.624585 136.79927 21.819829 2024-Nov-30 19:10 18 12 00.94 +34 10 12.6 292.510411 27.858195 n.a. n.a. 0.985686060538 -0.2764626 0.00099077600540 0.2504593 61.1502 /T 118.7994 67.5/ 0.4434 n.a. n.a. 54.474465 136.02675 20.997474 2024-Nov-30 19:20 18 12 31.75 +34 03 39.0 293.605350 26.144824 n.a. n.a. 0.985684961014 -0.2718257 0.00099176681926 0.2435298 61.1010 /T 118.8485 67.4/ 0.4349 n.a. n.a. 55.320220 135.25591 20.159058 2024-Nov-30 19:30 18 13 03.43 +33 57 04.6 294.711804 24.446297 n.a. n.a. 0.985683880092 -0.2671864 0.00099272889775 0.2361298 61.0535 /T 118.8960 67.4/ 0.4263 n.a. n.a. 56.161195 134.48798 19.304705 2024-Nov-30 19:40 18 13 35.97 +33 50 29.6 295.830959 22.763356 n.a. n.a. 0.985682817783 -0.2625444 0.00099366034786 0.2282565 61.0076 /T 118.9419 67.3/ 0.4178 n.a. n.a. 56.996713 133.72407 18.434580 2024-Nov-30 19:50 18 14 09.36 +33 43 54.3 296.963970 21.096765 n.a. n.a. 0.985681774097 -0.2578994 0.00099455926652 0.2199077 60.9636 /T 118.9859 67.2/ 0.4093 n.a. n.a. 57.826076 132.96520 17.548896 2024-Nov-30 20:00 18 14 43.62 +33 37 18.9 298.111969 19.447320 n.a. n.a. 0.985680749048 -0.2532510 0.00099542374394 0.2110822 60.9214 /T 119.0281 67.1/ 0.4008 n.a. n.a. 58.648563 132.21229 16.647903 2024-Nov-30 20:10 18 15 18.73 +33 30 43.7 299.276065 17.815843 n.a. n.a. 0.985679742649 -0.2485989 0.00099625186696 0.2017795 60.8811 /T 119.0683 67.1/ 0.3924 n.a. n.a. 59.463439 131.46618 15.731888 2024-Nov-30 20:20 18 15 54.69 +33 24 08.8 300.457351 16.203189 n.a. n.a. 0.985678754917 -0.2439428 0.00099704172235 0.1920002 60.8429 /T 119.1065 67.0/ 0.3841 n.a. n.a. 60.269951 130.72762 14.801177 2024-Nov-30 20:30 18 16 31.49 +33 17 34.6 301.656905 14.610244 n.a. n.a. 0.985677785868 -0.2392824 0.00099779140008 0.1817452 60.8067 /T 119.1427 66.9/ 0.3758 n.a. n.a. 61.067334 129.99731 13.856124 2024-Nov-30 20:40 18 17 09.12 +33 11 01.1 302.875790 13.037930 n.a. n.a. 0.985676835520 -0.2346172 0.00099849899648 0.1710167 60.7727 /T 119.1767 66.9/ 0.3677 n.a. n.a. 61.854811 129.27586 12.897114 2024-Nov-30 20:50 18 17 47.58 +33 04 28.7 304.115056 11.487206 n.a. n.a. 0.985675903892 -0.2299470 0.00099916261750 0.1598175 60.7409 /T 119.2085 66.8/ 0.3596 n.a. n.a. 62.631597 128.56381 11.924561 2024-Nov-30 21:00 18 18 26.86 +32 57 57.5 305.375739 9.959067 n.a. n.a. 0.985674991007 -0.2252715 0.00099978038174 0.1481510 60.7114 /T 119.2380 66.8/ 0.3516 n.a. n.a. 63.396903 127.86166 10.938901 2024-Nov-30 21:10 18 19 06.94 +32 51 27.6 306.658859 8.454548 n.a. n.a. 0.985674096885 -0.2205901 0.00100035042354 0.1360215 60.6842 /T 119.2651 66.7/ 0.3437 n.a. n.a. 64.149934 127.16984 9.9405957 2024-Nov-30 21:20 18 19 47.81 +32 44 59.4 307.965420 6.974725 n.a. n.a. 0.985673221551 -0.2159028 0.00100087089598 0.1234342 60.6594 /T 119.2899 66.6/ 0.3359 n.a. n.a. 64.889895 126.48873 8.9301250 2024-Nov-30 21:30 18 20 29.46 +32 38 32.9 309.296404 5.520716 n.a. n.a. 0.985672365029 -0.2112090 0.00100133997379 0.1103947 60.6370 /T 119.3123 66.6/ 0.3283 n.a. n.a. 65.615993 125.81866 7.9079876 2024-Nov-30 21:40 18 21 11.88 +32 32 08.3 310.652769 4.093680 n.a. n.a. 0.985671527347 -0.2065084 0.00100175585619 0.0969096 60.6171 /T 119.3322 66.5/ 0.3208 n.a. n.a. 66.327437 125.15993 6.8746984 2024-Nov-30 21:50 18 21 55.04 +32 25 45.9 312.035445 2.694821 n.a. n.a. 0.985670708531 -0.2018007 0.00100211676974 0.0829859 60.5997 /T 119.3496 66.5/ 0.3134 n.a. n.a. 67.023442 124.51278 5.8307862 2024-Nov-30 22:00 18 22 38.94 +32 19 25.7 313.445325 1.325387 n.a. n.a. 0.985669908612 -0.1970856 0.00100242097096 0.0686315 60.5848 /T 119.3645 66.4/ 0.3062 n.a. n.a. 67.703230 123.87745 4.7767923 2024-Nov-30 22:10 18 23 23.55 +32 13 07.9 314.883261 -0.013332 n.a. n.a. 0.985669127619 -0.1923626 0.00100266674900 0.0538549 60.5725 /T 119.3768 66.4/ 0.2991 n.a. n.a. 68.366034 123.25410 3.7132679 >..... 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 ***************************************************************************************************************************************************************************************************************************************************