API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* JPL/HORIZONS 415029 (2011 UL21) 2025-Jul-15 00:14:49 Rec #: 415029 (+COV) Soln.date: 2025-Jun-27_17:49:02 # obs: 2103 (1989-2024) IAU76/J2000 helio. ecliptic osc. elements (au, days, deg., period=Julian yrs): EPOCH= 2459277.5 ! 2021-Mar-04.00 (TDB) Residual RMS= .22227 EC= .6528147668162223 QR= .7369820510233599 TP= 2459313.6049066181 OM= 275.556237671966 W= 284.7765816227773 IN= 34.85117150260933 A= 2.122734438515848 MA= 348.4939355790438 ADIST= 3.508486826008335 PER= 3.0928 N= .318684232 ANGMOM= .018985498 DAN= 1.04423 DDN= 1.46142 L= 203.3749562 B= -33.5419699 MOID= .0203165 TP= 2021-Apr-09.1049066181 Asteroid physical parameters (km, seconds, rotational period in hours): GM= n.a. RAD= n.a. ROTPER= 2.732 H= 15.93 G= .150 B-V= n.a. ALBEDO= n.a. STYP= n.a. ASTEROID comments: 1: soln ref.= JPL#370, PHA OCC=0 radar( 3 delay, 0 Dop.) 2: source=ORB ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Tue Jul 15 00:14:49 2025 Pasadena, USA / Horizons ******************************************************************************* Target body name: 415029 (2011 UL21) {source: JPL#370} Center body name: Earth (399) {source: DE441} Center-site name: AUTH Observatory, Thessaloniki ******************************************************************************* Start time : A.D. 2024-Jun-25 00:00:00.0000 UT+03:00 Stop time : A.D. 2024-Jul-02 00:00:00.0000 UT+03:00 Step-size : 60 minutes ******************************************************************************* Target pole/equ : undefined Target radii : undefined Center geodetic : 22.9589, 40.6307043, .0900545 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 22.9589, 4847.46468, 4131.4444 {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 : Sun 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 Small-body perts: Yes {source: SB441-N16} Atmos refraction: NO (AIRLESS) RA format : HMS Time format : CAL Calendar mode : Mixed Julian/Gregorian Time zone : UT+03:00 EOP file : eop.250714.p251010 EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-JUL-14. PREDICTS-> 2025-OCT-09 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 ( 0.0,180.0=NO ),Local Hour Angle( 0.0=NO ) Table cut-offs 3: RA/DEC angular rate ( 0.0=NO ) ******************************************************************************* Initial IAU76/J2000 heliocentric ecliptic osculating elements (au, days, deg.): EPOCH= 2459277.5 ! 2021-Mar-04.00 (TDB) Residual RMS= .22227 EC= .6528147668162223 QR= .7369820510233599 TP= 2459313.6049066181 OM= 275.556237671966 W= 284.7765816227773 IN= 34.85117150260933 Equivalent ICRF heliocentric cartesian coordinates (au, au/d): X=-5.857133196149048E-01 Y= 7.151412032344981E-01 Z=-8.671862383820034E-02 VX=-5.153569918561386E-03 VY=-1.739967055377397E-02 VZ=-1.298953474149214E-02 Asteroid physical parameters (km, seconds, rotational period in hours): GM= n.a. RAD= n.a. ROTPER= 2.732 H= 15.93 G= .150 B-V= n.a. ALBEDO= n.a. STYP= n.a. *********************************************************************************************************************************************************************************************************** Date_(ZONE)_HR:MN R.A._____(ICRF)_____DEC Azi____(a-app)___Elev APmag S-brt delta deldot S-O-T /r S-T-O Cnst Sky_motion Sky_mot_PA RelVel-ANG Lun_Sky_Brt sky_SNR *********************************************************************************************************************************************************************************************************** $$SOE >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Jun-26 22:00 N 11 01 46.54 -32 10 58.0 225.537068 -0.265473 12.536 n.a. 0.04709420686196 -8.3849334 86.6076 /T 90.7357 Hya 42.584782 76.667020 -19.08174 n.a. n.a. >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Jun-27 22:00 N 12 22 35.76 -26 25 44.6 214.892137 13.943113 11.957 n.a. 0.04439411420524 -0.2743940 99.1606 /T 78.3869 Hya 47.819305 66.656020 -0.613494 n.a. n.a. 2024-Jun-27 23:00 A 12 25 51.64 -26 06 38.2 225.898383 7.209551 11.939 n.a. 0.04439253369167 0.1409724 99.6886 /T 77.8638 Hya 47.957581 66.292942 0.3130581 n.a. n.a. >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Jun-28 22:00 N 13 35 03.69 -18 02 56.1 202.920480 27.970907 11.686 n.a. 0.04658147508520 7.9676296 111.2106 /T 66.3833 Vir 43.349910 59.689706 18.078499 n.a. n.a. 2024-Jun-28 23:00 A 13 37 40.40 -17 41 05.9 216.982922 22.844460 11.683 n.a. 0.04677786460619 8.3510995 111.6439 /T 65.9480 Vir 43.077288 59.491039 18.925096 n.a. n.a. 2024-Jun-29 00:00 13 40 15.54 -17 19 16.8 229.383848 15.669042 11.680 n.a. 0.04698330879149 8.7194074 112.0723 /T 65.5173 Vir 42.816011 59.330593 19.727691 n.a. n.a. 2024-Jun-29 01:00 13 42 49.22 -16 57 30.2 240.295775 7.011848 11.678 n.a. 0.04719739334717 9.0685869 112.4961 /T 65.0908 Vir 42.559850 59.205835 20.480699 n.a. n.a. >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Jun-29 22:00 N 14 29 49.77 -09 52 58.4 190.785767 38.767956 11.721 n.a. 0.05306128963228 14.2334741 120.0447 /T 57.4350 Lib 33.349313 56.321963 33.642125 n.a. n.a. 2024-Jun-29 23:00 A 14 31 41.80 -09 34 36.6 208.298816 35.351509 11.728 n.a. 0.05340737343035 14.5268700 120.3228 /T 57.1487 Lib 32.965102 56.248837 34.318971 n.a. n.a. 2024-Jun-30 00:00 14 33 32.40 -09 16 25.7 223.645015 29.110079 11.735 n.a. 0.05376038034780 14.8080092 120.5954 /T 56.8675 Lib 32.605744 56.216154 34.949683 n.a. n.a. 2024-Jun-30 01:00 14 35 21.71 -08 58 26.0 236.679258 20.848932 11.742 n.a. 0.05411995626755 15.0720896 120.8632 /T 56.5909 Lib 32.266814 56.221107 35.529093 n.a. n.a. 2024-Jun-30 02:00 m 14 37 09.85 -08 40 37.9 247.905810 11.267963 11.750 n.a. 0.05448564091985 15.3151405 121.1265 /T 56.3184 Lib 31.942823 56.258440 36.055156 0.606 n.a. 2024-Jun-30 03:00 m 14 38 56.90 -08 23 01.9 258.003373 0.887636 11.758 n.a. 0.05485689120503 15.5342877 121.3859 /T 56.0497 Vir 31.627580 56.320870 36.528995 0.787 n.a. >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Jun-30 22:00 N 15 08 34.61 -03 28 27.4 179.751420 45.800852 11.937 n.a. 0.06251928974025 18.2388505 125.3881 /T 51.8419 Lib 23.982347 55.169567 45.182404 n.a. n.a. 2024-Jun-30 23:00 A 15 09 53.05 -03 14 53.0 200.413369 44.059921 11.949 n.a. 0.06296082757114 18.4558776 125.5428 /T 51.6740 Lib 23.664787 55.161308 45.701454 n.a. n.a. 2024-Jul-01 00:00 15 11 10.47 -03 01 29.3 218.729890 38.733567 11.960 n.a. 0.06340750010912 18.6646818 125.6938 /T 51.5096 Lib 23.374035 55.198285 46.175109 n.a. n.a. 2024-Jul-01 01:00 15 12 27.02 -02 48 16.3 233.869275 30.829263 11.972 n.a. 0.06385904385114 18.8598995 125.8418 /T 51.3481 Ser 23.107111 55.277194 46.598421 n.a. n.a. 2024-Jul-01 02:00 15 13 42.80 -02 35 13.9 246.377651 21.304256 11.984 n.a. 0.06431507410621 19.0368793 125.9870 /T 51.1891 Ser 22.859868 55.391754 46.969591 n.a. n.a. 2024-Jul-01 03:00 m 15 14 57.89 -02 22 22.3 257.170063 10.845345 11.996 n.a. 0.06477510601497 19.1919948 126.1300 /T 51.0322 Ser 22.627254 55.533224 47.289998 0.415 n.a. 2024-Jul-01 04:00 Am 15 16 12.35 -02 09 41.3 267.098071 -0.076702 12.008 n.a. 0.06523858232426 19.3228900 126.2709 /T 50.8773 Ser 22.403622 55.691110 47.564022 n.a. n.a. >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< 2024-Jul-01 22:00 N 15 36 01.10 +01 10 43.4 170.561585 50.089206 12.226 n.a. 0.07382631551827 20.6754907 128.3118 /T 48.5692 Ser 17.171777 55.047911 53.456414 n.a. n.a. 2024-Jul-01 23:00 A 15 36 57.10 +01 20 27.9 193.666257 49.835638 12.239 n.a. 0.07432589493046 20.8441844 128.3916 /T 48.4730 Ser 16.943405 55.070538 53.860357 n.a. n.a. 2024-Jul-02 00:00 15 37 52.43 +01 30 04.3 214.685373 45.356941 12.252 n.a. 0.07482948473308 21.0078350 128.4694 /T 48.3786 Ser 16.739000 55.145356 54.219967 n.a. n.a. $$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: A time-zone correction has been requested. See header. 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 symbol: '*' 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 (OBSERVING SITE) The solar-presence symbol is immediately followed by a lunar-presence symbol: 'm' Refracted upper-limb of Moon on or above apparent horizon ' ' Refracted upper-limb of Moon below apparent horizon OR geocentric ephemeris '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 asteroids' approximate apparent airless visual magnitude and surface brightness using the standard IAU H-G system magnitude model: APmag = H + 5*log10(delta) + 5*log10(r) - 2.5*log10((1-G)*phi_1 + G*phi_2) For solar phase angles >90 deg, the error could exceed 1 magnitude. For phase angles >120 degrees, output values are rounded to the nearest integer to indicate error could be large and unknown. 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 '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 'Cnst' = Constellation ID; the 3-letter abbreviation for the name of the constellation containing the target centers' astrometric position, as defined by IAU (1930) boundary delineation. See documentation for list of abbreviations. '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 'Lun_Sky_Brt sky_SNR' = Sky brightness due to moonlight scattered by Earth's atmosphere at the target's position in the sky. "sky_SNR" is the visual signal-to-noise ratio (SNR) of the target's surface brightness relative to background sky. Output only for topocentric Earth observers when both the Moon and target are above the local horizon and the Sun is in astronomical twilight (or further) below the horizon, and the target is not the Moon or Sun. If all conditions are not met, "n.a." is output. Galactic brightness, local sky light-pollution and weather are NOT considered. Lunar opposition surge is considered. The value returned is accurate under ideal conditions at the approximately 8-23% level, so is a useful but not definitive value. If the target-body radius is also known, "sky_SNR" is output. This is the approximate visual signal-to-noise ratio of the target's brightness divided by lunar sky brightness. When sky_SNR < 1, the target is dimmer than the ideal moonlight-scattering background sky, so unlikely to be detectable at visual wavelengths. In practice, visibility requires sky_SNR > 1 and a detector sensitive enough to reach the target's magnitude, even if it isn't washed out by moonlight. When relating magnitudes and brightness values, keep in mind their logarithmic relationship m2-m1 = -2.5*log_10(b2/b1). UNITS: VISUAL MAGNITUDES / ARCSECOND^2, and unitless ratio 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 ***********************************************************************************************************************************************************************************************************