******************************************************************************* JPL/HORIZONS 1P/Halley 2024-Apr-25 05:54:06 Rec #:90000015 Soln.date: - # obs: 161 (1607-1759) IAU76/J2000 helio. ecliptic osc. elements (au, days, deg., period=Julian yrs): EPOCH= 2026840.5 ! 837-Mar-10.0000000 (TDB) RMSW= n.a. EC= .9678099999999999 QR= .5823199999999999 TP= 2026830.77 OM= 44.93 W= 100.101 IN= 163.447 A= 18.09009009009006 MA= .1246395348713476 ADIST= 35.59786018018011 PER= 76.94303213720001 N= .012809819 ANGMOM= .018414243 DAN= 1.38016 DDN= .97962 L= 304.4018499 B= 16.2892251 TP= 837-Feb-28.2700000000 Comet physical (GM= km^3/s^2; RAD= km): GM= n.a. RAD= 5.5 M1= 5.5 M2= 13.6 k1= 8. k2= 5. PHCOF= .030 COMET comments 1: soln ref.= SAO/837 2: k1=8.0, k2=5.0, phase coef.=0.03;epoch may be 2026841.0 (hour ambiguous: 12h/0h) ******************************************************************************* ******************************************************************************* Ephemeris / WWW_USER Thu Apr 25 05:54:06 2024 Pasadena, USA / Horizons ******************************************************************************* Target body name: 1P/Halley {source: SAO/837 20} Center body name: Earth (399) {source: DE441} Center-site name: GEOCENTRIC ******************************************************************************* Start time : A.D. 0837-Apr-10 12:00:00.0000 UT Stop time : A.D. 0837-Apr-10 12:30:00.0000 UT Step-size : 1 minutes ******************************************************************************* Target pole/equ : undefined Target radii : 5.5 km Center geodetic : 0.0, 0.0, -6378.137 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 0.0, 0.0, 0.0 {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 EOP file : eop.240424.p240718 EOP coverage : DATA-BASED 1962-JAN-20 TO 2024-APR-24. PREDICTS-> 2024-JUL-17 Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass (>38.000=NO), Daylight (NO ) 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= 2026840.5 ! 837-Mar-10.0000000 (TDB) RMSW= n.a. EC= .9678099999999999 QR= .5823199999999999 TP= 2026830.77 OM= 44.93 W= 100.101 IN= 163.447 Equivalent ICRF heliocentric cartesian coordinates (au, au/d): X= 4.893001978162831E-02 Y=-6.080489167656591E-01 Z=-1.140726637116969E-01 VX=-2.837657606222098E-02 VY=-8.535407512545095E-03 VZ=-7.694752642186252E-03 Comet physical (GM= km^3/s^2; RAD= km): GM= n.a. RAD= 5.5 M1= 5.5 M2= 13.6 k1= 8. k2= 5. PHCOF= .030 ********************************************************************************************* Date__(UT)__HR:MN r rdot delta deldot S-O-T /r ********************************************************************************************* $$SOE 0837-Apr-10 12:00 1.033938993131 26.7589621 0.03342177294902 -0.6589684 138.2885 /L 0837-Apr-10 12:01 1.033949725515 26.7589974 0.03342151886699 -0.6080883 138.3169 /L 0837-Apr-10 12:02 1.033960457913 26.7590328 0.03342128519108 -0.5572071 138.3452 /L 0837-Apr-10 12:03 1.033971190321 26.7590681 0.03342107192177 -0.5063249 138.3736 /L 0837-Apr-10 12:04 1.033981922742 26.7591034 0.03342087905944 -0.4554417 138.4019 /L 0837-Apr-10 12:05 1.033992655176 26.7591387 0.03342070660444 -0.4045576 138.4303 /L 0837-Apr-10 12:06 1.034003387621 26.7591740 0.03342055455709 -0.3536728 138.4585 /L 0837-Apr-10 12:07 1.034014120080 26.7592093 0.03342042291769 -0.3027873 138.4868 /L 0837-Apr-10 12:08 1.034024852551 26.7592446 0.03342031168647 -0.2519012 138.5150 /L 0837-Apr-10 12:09 1.034035585034 26.7592799 0.03342022086366 -0.2010146 138.5433 /L 0837-Apr-10 12:10 1.034046317529 26.7593152 0.03342015044942 -0.1501276 138.5714 /L 0837-Apr-10 12:11 1.034057050036 26.7593505 0.03342010044389 -0.0992403 138.5996 /L 0837-Apr-10 12:12 1.034067782556 26.7593858 0.03342007084717 -0.0483528 138.6277 /L 0837-Apr-10 12:13 1.034078515088 26.7594211 0.03342006165932 0.0025348 138.6558 /L 0837-Apr-10 12:14 1.034089247634 26.7594563 0.03342007288036 0.0534224 138.6839 /L 0837-Apr-10 12:15 1.034099980191 26.7594916 0.03342010451029 0.1043100 138.7120 /L 0837-Apr-10 12:16 1.034110712760 26.7595269 0.03342015654904 0.1551974 138.7400 /L 0837-Apr-10 12:17 1.034121445341 26.7595621 0.03342022899653 0.2060845 138.7680 /L 0837-Apr-10 12:18 1.034132177935 26.7595974 0.03342032185263 0.2569713 138.7960 /L 0837-Apr-10 12:19 1.034142910542 26.7596326 0.03342043511720 0.3078576 138.8240 /L 0837-Apr-10 12:20 1.034153643160 26.7596678 0.03342056879000 0.3587434 138.8519 /L 0837-Apr-10 12:21 1.034164375791 26.7597031 0.03342072287082 0.4096286 138.8798 /L 0837-Apr-10 12:22 1.034175108434 26.7597383 0.03342089735937 0.4605131 138.9077 /L 0837-Apr-10 12:23 1.034185841089 26.7597735 0.03342109225535 0.5113967 138.9355 /L 0837-Apr-10 12:24 1.034196573756 26.7598088 0.03342130755840 0.5622794 138.9634 /L 0837-Apr-10 12:25 1.034207306438 26.7598440 0.03342154326816 0.6131612 138.9912 /L 0837-Apr-10 12:26 1.034218039130 26.7598792 0.03342179938416 0.6640418 139.0189 /L 0837-Apr-10 12:27 1.034228771834 26.7599144 0.03342207590596 0.7149212 139.0467 /L 0837-Apr-10 12:28 1.034239504551 26.7599496 0.03342237283305 0.7657994 139.0744 /L 0837-Apr-10 12:29 1.034250237280 26.7599848 0.03342269016491 0.8166762 139.1021 /L 0837-Apr-10 12:30 1.034260970021 26.7600200 0.03342302790095 0.8675515 139.1297 /L $$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. '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 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 ********************************************************************************************* !$$SOF COMMAND = '90000015' START_TIME = '837AD-Apr-10 12:00' STOP_TIME = '837AD-Apr-10 12:30' STEP_SIZE = '1 minutes' QUANTITIES = '19,20,23'