******************************************************************************* JPL/HORIZONS 26P/Grigg-Skjellerup 2025-Dec-12 17:51:59 Rec #:90000375 Soln.date: - # obs: 220 (1982-2008) IAU76/J2000 helio. ecliptic osc. elements (au, days, deg., period=Julian yrs): EPOCH= 2450680.5 ! 1997-Aug-20.0000000 (TDB) RMSW= n.a. EC= .663805 QR= .996811 TP= 2450690.804 OM= 213.3092 W= 359.3315 IN= 21.0867 A= 2.964978658219188 MA= 358.0108040497456 ADIST= 4.933146316438376 PER= 5.1055267946575 N= .193050849 ANGMOM= .022153332 DAN= .9968399999999999 DDN= 4.93248 L= 212.6854611 B= -.2405083 TP= 1997-Aug-30.3040000000 Comet physical (GM= km^3/s^2; RAD= km): GM= n.a. RAD= 1.3 M1= 16.5 M2= n.a. k1= 5.5 k2= n.a. PHCOF= n.a. COMET comments 1: soln ref.= SAO/1997 2: k1=5.5;non-gravs. considered; 2008 SAO Comet Catalog ******************************************************************************* ******************************************************************************* Ephemeris / WWW_USER Fri Dec 12 17:51:59 2025 Pasadena, USA / Horizons ******************************************************************************* Target body name: 26P/Grigg-Skjellerup {source: SAO/199720} Center body name: Earth (399) {source: DE441} Center-site name: GEOCENTRIC ******************************************************************************* Start time : A.D. 2023-Dec-25 00:00:00.0000 UT Stop time : A.D. 2023-Dec-26 00:00:00.0000 UT Step-size : 60 minutes ******************************************************************************* Target pole/equ : undefined Target radii : 1.3 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.251212.p260310 EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-DEC-12. PREDICTS-> 2026-MAR-09 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= 2450680.5 ! 1997-Aug-20.0000000 (TDB) RMSW= n.a. EC= .663805 QR= .996811 TP= 2450690.804 OM= 213.3092 W= 359.3315 IN= 21.0867 Equivalent ICRF heliocentric cartesian coordinates (au, au/d): X=-9.402466718528818E-01 Y=-2.875718695979415E-01 Z=-2.184899098714102E-01 VX= 8.453285844015930E-03 VY=-2.040198084892633E-02 VZ=-2.804992735638094E-04 Comet physical (GM= km^3/s^2; RAD= km): GM= n.a. RAD= 1.3 M1= 16.5 M2= n.a. k1= 5.5 k2= n.a. PHCOF= n.a. ********************************************************************************************************************** Date__(UT)__HR:MN r rdot delta deldot VmagSn VmagOb S-O-T /r ********************************************************************************************************************** $$SOE 2023-Dec-25 00:00 1.083911776443 -0.0976783 1.79637066981000 0.0328503 36.6439062 57.5343047 31.2959 /L 2023-Dec-25 01:00 1.083909565928 -0.0860375 1.79637157553159 0.0424273 36.6439519 57.5314908 31.2956 /L 2023-Dec-25 02:00 1.083907635545 -0.0743966 1.79637271164811 0.0519994 36.6439918 57.5286724 31.2953 /L 2023-Dec-25 03:00 1.083905985295 -0.0627556 1.79637407804273 0.0615667 36.6440259 57.5258494 31.2950 /L 2023-Dec-25 04:00 1.083904615180 -0.0511145 1.79637567459821 0.0711291 36.6440543 57.5230218 31.2948 /L 2023-Dec-25 05:00 1.083903525203 -0.0394734 1.79637750119695 0.0806866 36.6440769 57.5201896 31.2945 /L 2023-Dec-25 06:00 1.083902715364 -0.0278323 1.79637955772104 0.0902392 36.6440937 57.5173528 31.2942 /L 2023-Dec-25 07:00 1.083902185664 -0.0161911 1.79638184405226 0.0997869 36.6441047 57.5145114 31.2940 /L 2023-Dec-25 08:00 1.083901936104 -0.0045498 1.79638436007193 0.1093296 36.6441100 57.5116654 31.2938 /L 2023-Dec-25 09:00 1.083901966684 0.0070914 1.79638710566113 0.1188674 36.6441095 57.5088147 31.2935 /L 2023-Dec-25 10:00 1.083902277405 0.0187326 1.79639008070058 0.1284002 36.6441032 57.5059594 31.2933 /L 2023-Dec-25 11:00 1.083902868265 0.0303738 1.79639328507060 0.1379281 36.6440912 57.5030994 31.2931 /L 2023-Dec-25 12:00 1.083903739264 0.0420149 1.79639671865125 0.1474509 36.6440733 57.5002348 31.2928 /L 2023-Dec-25 13:00 1.083904890401 0.0536560 1.79640038132223 0.1569688 36.6440497 57.4973656 31.2926 /L 2023-Dec-25 14:00 1.083906321675 0.0652971 1.79640427296287 0.1664816 36.6440204 57.4944916 31.2924 /L 2023-Dec-25 15:00 1.083908033083 0.0769380 1.79640839345219 0.1759894 36.6439852 57.4916130 31.2922 /L 2023-Dec-25 16:00 1.083910024625 0.0885789 1.79641274266890 0.1854921 36.6439443 57.4887297 31.2920 /L 2023-Dec-25 17:00 1.083912296296 0.1002197 1.79641732049134 0.1949898 36.6438976 57.4858418 31.2918 /L 2023-Dec-25 18:00 1.083914848096 0.1118603 1.79642212679754 0.2044824 36.6438452 57.4829491 31.2916 /L 2023-Dec-25 19:00 1.083917680020 0.1235008 1.79642716146522 0.2139699 36.6437870 57.4800517 31.2915 /L 2023-Dec-25 20:00 1.083920792065 0.1351412 1.79643242437171 0.2234524 36.6437230 57.4771496 31.2913 /L 2023-Dec-25 21:00 1.083924184228 0.1467814 1.79643791539410 0.2329297 36.6436532 57.4742427 31.2911 /L 2023-Dec-25 22:00 1.083927856505 0.1584214 1.79644363440911 0.2424018 36.6435776 57.4713312 31.2909 /L 2023-Dec-25 23:00 1.083931808891 0.1700613 1.79644958129314 0.2518689 36.6434963 57.4684149 31.2908 /L 2023-Dec-26 00:00 1.083936041382 0.1817009 1.79645575592226 0.2613307 36.6434092 57.4654938 31.2906 /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 'VmagSn VmagOb' = Magnitude of target centers' velocity with respect to the Sun ("VmagSn") and the observer ("VmagOb") at the time light left the target center to be observed (print time minus down-leg light-time). These are absolute values of the velocity vectors (total speeds) and do NOT indicate direction of motion. Units: 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/horizons_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov ********************************************************************************************************************** !$$SOF COMMAND = '90000375' QUANTITIES = '19,20,22,23' START_TIME = '2023-Dec-25' STEP_SIZE = '1 hour' STOP_TIME = '2023-Dec-26'