API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: May 07, 2025 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 2025-May-06 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_25311 2010-Feb-25 2025-Nov-07 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Tue May 13 08:40:56 2025 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-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 : 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.250512.p250808 EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-MAY-12. PREDICTS-> 2025-AUG-07 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 2024-Oct-31 00:00 19 42 32.95 +19 10 39.9 291.158177 5.055649 n.a. n.a. 0.992817983949 0.1031733 0.00061284946797 -1.3539024 85.7184 /T 94.2461 99.3/ 2.0496 n.a. n.a. 142.51199 136.87045 -52.05526 2024-Oct-31 00:10 19 43 42.70 +18 53 07.1 292.345481 3.304710 n.a. n.a. 0.992818398773 0.1036675 0.00060737170919 -1.3775498 85.8936 /T 94.0712 99.5/ 2.0248 n.a. n.a. 146.40682 136.44319 -52.03665 2024-Oct-31 00:20 19 44 54.80 +18 35 12.9 293.542341 1.567364 n.a. n.a. 0.992818815401 0.1040715 0.00060179740528 -1.4020415 86.0772 /T 93.8879 99.7/ 2.0002 n.a. n.a. 150.43979 136.03303 -52.02745 2024-Oct-31 00:30 19 46 09.29 +18 16 56.4 294.749986 -0.155870 n.a. n.a. 0.992819233458 0.1043788 0.00059612315476 -1.4273849 86.2693 /T 93.6961 99.8/ 1.9759 n.a. n.a. 154.61966 135.64048 -52.02695 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Oct-31 17:20 C 15 59 51.85 +42 42 21.8 291.962461 48.445443 n.a. n.a. 0.992364073063 -0.8935369 0.00057142979608 1.8928549 61.1037 /T 118.8677 64.5/ 0.7200 n.a. n.a. 127.78390 106.57354 64.999083 2024-Oct-31 17:30 C 16 01 41.99 +42 36 11.0 292.514522 46.980501 n.a. n.a. 0.992360515321 -0.8806365 0.00057898644969 1.8754031 61.1644 /T 118.8067 64.6/ 0.7096 n.a. n.a. 126.30965 107.03573 64.761322 2024-Oct-31 17:40 N 16 03 30.46 +42 29 55.0 293.089241 45.514441 n.a. n.a. 0.992357008608 -0.8680875 0.00058647362550 1.8582011 61.2246 /T 118.7461 64.8/ 0.6991 n.a. n.a. 124.95138 107.46092 64.511780 2024-Oct-31 17:50 N 16 05 17.38 +42 23 34.4 293.685933 44.048063 n.a. n.a. 0.992353551549 -0.8558731 0.00059389226219 1.8412177 61.2845 /T 118.6857 64.9/ 0.6886 n.a. n.a. 123.69871 107.84971 64.250947 2024-Oct-31 18:00 N 16 07 02.87 +42 17 10.0 294.304028 42.582154 n.a. n.a. 0.992350142833 -0.8439778 0.00060124317558 1.8244229 61.3445 /T 118.6254 65.0/ 0.6779 n.a. n.a. 122.54213 108.20283 63.979292 2024-Oct-31 18:10 N 16 08 47.02 +42 10 42.2 294.943055 41.117488 n.a. n.a. 0.992346781211 -0.8323869 0.00060852706453 1.8077882 61.4046 /T 118.5648 65.1/ 0.6672 n.a. n.a. 121.47293 108.52109 63.697260 2024-Oct-31 18:20 A 16 10 29.93 +42 04 11.7 295.602632 39.654834 n.a. n.a. 0.992343465490 -0.8210866 0.00061574451673 1.7912868 61.4651 /T 118.5040 65.2/ 0.6564 n.a. n.a. 120.48309 108.80539 63.405278 2024-Oct-31 18:30 A 16 12 11.69 +41 57 38.9 296.282460 38.194956 n.a. n.a. 0.992340194529 -0.8100642 0.00062289601421 1.7748928 61.5262 /T 118.4425 65.3/ 0.6455 n.a. n.a. 119.56528 109.05668 63.103745 2024-Oct-31 18:40 A 16 13 52.39 +41 51 04.5 296.982314 36.738611 n.a. n.a. 0.992336967239 -0.7993075 0.00062998193871 1.7585820 61.5880 /T 118.3803 65.4/ 0.6345 n.a. n.a. 118.71273 109.27598 62.793041 2024-Oct-31 18:50 16 15 32.09 +41 44 28.7 297.702035 35.286558 n.a. n.a. 0.992333782578 -0.7888052 0.00063700257684 1.7423312 61.6507 /T 118.3173 65.5/ 0.6235 n.a. n.a. 117.91924 109.46435 62.473521 2024-Oct-31 19:00 16 17 10.87 +41 37 52.2 298.441528 33.839554 n.a. n.a. 0.992330639546 -0.7785466 0.00064395812516 1.7261186 61.7144 /T 118.2532 65.6/ 0.6125 n.a. n.a. 117.17910 109.62289 62.145519 2024-Oct-31 19:10 16 18 48.80 +41 31 15.3 299.200752 32.398360 n.a. n.a. 0.992327537187 -0.7685215 0.00065084869504 1.7099237 61.7793 /T 118.1879 65.7/ 0.6014 n.a. n.a. 116.48703 109.75272 61.809346 2024-Oct-31 19:20 16 20 25.92 +41 24 38.5 299.979721 30.963737 n.a. n.a. 0.992324474583 -0.7587205 0.00065767431749 1.6937268 61.8455 /T 118.1214 65.8/ 0.5902 n.a. n.a. 115.83818 109.85497 61.465290 2024-Oct-31 19:30 16 22 02.30 +41 18 02.1 300.778494 29.536456 n.a. n.a. 0.992321450853 -0.7491346 0.00066443494776 1.6775098 61.9131 /T 118.0533 65.9/ 0.5791 n.a. n.a. 115.22807 109.93079 61.113620 2024-Oct-31 19:40 16 23 37.99 +41 11 26.6 301.597174 28.117294 n.a. n.a. 0.992318465153 -0.7397553 0.00067113046993 1.6612554 61.9823 /T 117.9837 65.9/ 0.5679 n.a. n.a. 114.65257 109.98133 60.754586 2024-Oct-31 19:50 16 25 13.02 +41 04 52.3 302.435905 26.707034 n.a. n.a. 0.992315516671 -0.7305745 0.00067776070131 1.6449475 62.0532 /T 117.9125 66.0/ 0.5567 n.a. n.a. 114.10784 110.00771 60.388417 2024-Oct-31 20:00 16 26 47.45 +40 58 19.5 303.294866 25.306473 n.a. n.a. 0.992312604624 -0.7215847 0.00068432539684 1.6285711 62.1259 /T 117.8395 66.1/ 0.5455 n.a. n.a. 113.59035 110.01108 60.015324 2024-Oct-31 20:10 16 28 21.31 +40 51 48.6 304.174271 23.916419 n.a. n.a. 0.992309728262 -0.7127786 0.00069082425332 1.6121122 62.2004 /T 117.7646 66.2/ 0.5343 n.a. n.a. 113.09682 109.99253 59.635502 2024-Oct-31 20:20 16 29 54.64 +40 45 19.9 305.074364 22.537693 n.a. n.a. 0.992306886862 -0.7041494 0.00069725691354 1.5955579 62.2769 /T 117.6877 66.3/ 0.5231 n.a. n.a. 112.62418 109.95317 59.249131 2024-Oct-31 20:30 16 31 27.45 +40 38 53.7 305.995415 21.171130 n.a. n.a. 0.992304079727 -0.6956906 0.00070362297044 1.5788963 62.3554 /T 117.6089 66.4/ 0.5119 n.a. n.a. 112.16963 109.89407 58.856374 2024-Oct-31 20:40 16 32 59.80 +40 32 30.3 306.937719 19.817583 n.a. n.a. 0.992301306186 -0.6873961 0.00070992197107 1.5621163 62.4361 /T 117.5279 66.5/ 0.5008 n.a. n.a. 111.73051 109.81627 58.457380 2024-Oct-31 20:50 16 34 31.69 +40 26 10.0 307.901593 18.477923 n.a. n.a. 0.992298565593 -0.6792599 0.00071615342051 1.5452081 62.5189 /T 117.4447 66.6/ 0.4897 n.a. n.a. 111.30439 109.72077 58.052287 2024-Oct-31 21:00 16 36 03.15 +40 19 53.0 308.887371 17.153038 n.a. n.a. 0.992295857323 -0.6712766 0.00072231678573 1.5281626 62.6039 /T 117.3594 66.7/ 0.4786 n.a. n.a. 110.88898 109.60858 57.641220 2024-Oct-31 21:10 16 37 34.20 +40 13 39.5 309.895401 15.843838 n.a. n.a. 0.992293180775 -0.6634408 0.00072841149939 1.5109716 62.6912 /T 117.2717 66.8/ 0.4676 n.a. n.a. 110.48213 109.48065 57.224292 2024-Oct-31 21:20 16 39 04.86 +40 07 29.9 310.926046 14.551253 n.a. n.a. 0.992290535366 -0.6557475 0.00073443696349 1.4936281 62.7808 /T 117.1818 66.9/ 0.4567 n.a. n.a. 110.08186 109.33788 56.801608 2024-Oct-31 21:30 16 40 35.14 +40 01 24.3 311.979673 13.276235 n.a. n.a. 0.992287920535 -0.6481918 0.00074039255308 1.4761258 62.8727 /T 117.0895 67.0/ 0.4458 n.a. n.a. 109.68630 109.18118 56.373263 2024-Oct-31 21:40 16 42 05.05 +39 55 23.0 313.056655 12.019761 n.a. n.a. 0.992285335740 -0.6407692 0.00074627761974 1.4584591 62.9671 /T 116.9948 67.1/ 0.4350 n.a. n.a. 109.29369 109.01141 55.939343 2024-Oct-31 21:50 16 43 34.61 +39 49 26.1 314.157366 10.782830 n.a. n.a. 0.992282780455 -0.6334753 0.00075209149512 1.4406236 63.0638 /T 116.8978 67.2/ 0.4243 n.a. n.a. 108.90240 108.82937 55.499927 2024-Oct-31 22:00 16 45 03.81 +39 43 33.9 315.282175 9.566467 n.a. n.a. 0.992280254173 -0.6263058 0.00075783349435 1.4226157 63.1629 /T 116.7983 67.3/ 0.4136 n.a. n.a. 108.51087 108.63586 55.055086 2024-Oct-31 22:10 16 46 32.68 +39 37 46.5 316.431444 8.371720 n.a. n.a. 0.992277756403 -0.6192568 0.00076350291939 1.4044323 63.2645 /T 116.6964 67.4/ 0.4031 n.a. n.a. 108.11766 108.43163 54.604887 2024-Oct-31 22:20 16 48 01.20 +39 32 04.1 317.605520 7.199663 n.a. n.a. 0.992275286669 -0.6123244 0.00076909906230 1.3860715 63.3685 /T 116.5921 67.5/ 0.3927 n.a. n.a. 107.72139 108.21740 54.149390 2024-Oct-31 22:30 16 49 29.40 +39 26 26.8 318.804734 6.051395 n.a. n.a. 0.992272844512 -0.6055050 0.00077462120848 1.3675320 63.4749 /T 116.4853 67.6/ 0.3824 n.a. n.a. 107.32078 107.99387 53.688649 2024-Oct-31 22:40 16 50 57.25 +39 20 54.9 320.029391 4.928040 n.a. n.a. 0.992270429484 -0.5987951 0.00078006863979 1.3488133 63.5838 /T 116.3761 67.7/ 0.3722 n.a. n.a. 106.91461 107.76169 53.222715 2024-Oct-31 22:50 16 52 24.78 +39 15 28.4 321.279768 3.830747 n.a. n.a. 0.992268041154 -0.5921913 0.00078544063761 1.3299156 63.6950 /T 116.2646 67.8/ 0.3622 n.a. n.a. 106.50174 107.52149 52.751637 2024-Oct-31 23:00 16 53 51.97 +39 10 07.5 322.556106 2.760684 n.a. n.a. 0.992265679102 -0.5856904 0.00079073648587 1.3108400 63.8087 /T 116.1506 68.0/ 0.3523 n.a. n.a. 106.08107 107.27387 52.275456 2024-Oct-31 23:10 16 55 18.82 +39 04 52.3 323.858605 1.719047 n.a. n.a. 0.992263342922 -0.5792894 0.00079595547397 1.2915881 63.9247 /T 116.0343 68.1/ 0.3425 n.a. n.a. 105.65159 107.01939 51.794214 2024-Oct-31 23:20 16 56 45.33 +38 59 43.0 325.187416 0.707048 n.a. n.a. 0.992261032220 -0.5729852 0.00080109689963 1.2721624 64.0430 /T 115.9157 68.2/ 0.3329 n.a. n.a. 105.21233 106.75859 51.307949 2024-Oct-31 23:30 16 58 11.49 +38 54 39.5 326.542633 -0.274082 n.a. n.a. 0.992258746613 -0.5667750 0.00080616007167 1.2525661 64.1636 /T 115.7947 68.3/ 0.3234 n.a. n.a. 104.76237 106.49199 50.816697 >..... 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 ***************************************************************************************************************************************************************************************************************************************************