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  Written:  1997 March 11
 Modified:  2004 May 28 11:38
       by:  Alan B. Chamberlin
      for:  Solar System Dynamics Group
            Jet Propulsion Laboratory
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<HEAD>
<TITLE>Ephemeris Generator</TITLE>
  <META NAME="Title"             CONTENT="Ephemeris Generator">
  <META NAME="Information_ID"    CONTENT="JPLSSD-1.0">
  <META NAME="Date"              CONTENT="2004 May 28 11:38">
  <META NAME="Version_ID"        CONTENT="1.0">
  <META NAME="Author"            CONTENT="Alan B. Chamberlin">
  <META NAME="Creator"           CONTENT="Alan B. Chamberlin">
  <META NAME="Custodian"         CONTENT="Alan B. Chamberlin">
  <META NAME="Custodian_Contact" CONTENT="webmaster@ssd.jpl.nasa.gov">
  <META NAME="Description"       CONTENT="">
  <META NAME="Keywords"          CONTENT="Ephemeris Ephemerides Orbital Dynamics Orbital Elements Orbits Horizons Planets Satellites Comets Asteroids Physical Parameters Astronomical Constants Solar System Dynamics JPL">
</HEAD>
<BODY BGCOLOR="FFFFFF" >
<H1> Ephemeris Generator
</H1>
<H3>Ephemeris Settings</H3>
<PRE>
      Target Body: <B>Comet 2P/Encke [2003]</B>
Observer Location: <B>Los Angeles  CA</B>
      Coordinates: <B>118&#176;14'27.6''W  34&#176;03'15.1''N</B>
  From: <B>A.D. 2004-07-03 00:00 UT</B>
    To: <B>A.D. 2008-07-18 00:00   </B>
  Step: <B>30 day</B>
Format: <B>Calendar Date and Time</B>
Output Quantities: <B>13 19 22 27-28</B>
 Ref. Frame  RA/Dec Format: <B>J2000  Degrees</B>
Apparent Coordinates Model: <B>Airless</B>
</PRE>
<HR>
<H2>HORIZONS Generated Ephemeris</H2><PRE>
*******************************************************************************
Ephemeris / WWW_USER Sat Jul  3 15:54:35 2004  Pasadena  USA     / Horizons    
*******************************************************************************
Target body name: 2P/Encke                        {source: JPL#K033/8}
Center body name: Earth (399)                     {source: DE-0406LE-0406}
Center-site name: (User Defined Site)
*******************************************************************************
Start time      : A.D. 2004-Jul-03 00:00:00.0000 UT      
Stop  time      : A.D. 2008-Jul-18 00:00:00.0000 UT      
Step-size       : 43200 minutes
*******************************************************************************
Center geodetic : 241.759000 34.0542     -0.00{E-lon(deg) Lat(deg) Alt(km)}
Center cylindric: 241.759000 5289.894   3551.42{E-lon(deg) Dxy(km) Dz(km)}
Center pole/equ : High-precision EOP model        {East-longitude +}
Center radii    : 6378.1 x 6378.1 x 6356.8 km     {Equator  meridian  pole}    
Target pole/equ : No model available
Target radii    : 2.4 km                                                       
Target primary  : Sun                             {source: DE-0406LE-0406}
Interfering body: MOON (Req= 1737.400) km         {source: DE-0406LE-0406}
Deflecting body : Sun                             {source: DE-0406LE-0406}
Deflecting GM   : 1.3271E+11 km^3/s^2                                          
Small perturbers: Ceres  Pallas  Vesta            {source: SB405-CPV-2}
Small body GMs  : 6.32E+01 1.43E+01  1.78E+01 km^3/s^2                        
Atmos refraction: NO (AIRLESS)
RA format       : DEG
Time format     : CAL 
EOP file        : eop.040702.p040923                                           
EOP coverage    : DATA-BASED 1962-JAN-20 TO 2004-JUL-02. PREDICTS-> 2004-SEP-22
Units conversion: 1 AU= 149597870.691 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 )                           
Table format    : Comma Separated Values (spreadsheet)
*******************************************************************************
Initial FK5/J2000.0 heliocentric ecliptic osculating elements (AU  DAYS  DEG):
  EPOCH=  2453001.5 != 2003-Dec-28.0000000 (CT)   Residual RMS= .66082         
    EC= .8473387400958473  QR= .3384624529137247  TP= 2453003.378588202        
    OM= 334.5872055524041  W= 186.4990312834768   IN= 11.76957788090182        
Comet physical & dynamic parameters (KM  SEC; A1 A2 A3=AU/d^2; DT=days):
    GM= n.a.               RAD= 2.4               A1= 9.177555D-11             
    A2= -5.482499D-12      A3= n.a.               DT= n.a.                     
    M1= 9.8                M2= 14.5               k1= n.a.                     
    k2= 5.                 PHCOF= .030                                         
*************************************************************************************************
 Date__(UT)__HR:MN      Ang-diam              r      rdot    VmagSn   VmagOb
*************************************************************************************************
 2004-Jul-03 00:00 *   0.004 2.636226 13.89641 16.52109 15.34907
 2004-Aug-02 00:00 *   0.004 2.863085 12.32621 14.81971 22.22325
 2004-Sep-01 00:00 *   0.003 3.064458 10.94622 13.37557 28.54489
 2004-Oct-01 00:00 *   0.003 3.2432 9.70815 12.12442 33.60379
 2004-Oct-31 00:00 *   0.002 3.401469 8.57864 11.0251 37.11669
 2004-Nov-30 00:00 *   0.002 3.540933 7.53373 10.05063 38.96959
 2004-Dec-30 00:00 *   0.002 3.662897 6.55558 9.18356 39.20255
 2005-Jan-29 00:00 *   0.001 3.768394 5.63045 8.4133 38.02806
 2005-Feb-28 00:00 *   0.001 3.858246 4.7475 7.73459 35.81711
 2005-Mar-30 00:00 *   0.001 3.933104 3.89796 7.14673 33.03813
 2005-Apr-29 00:00 *   0.001 3.99348 3.07449 6.65279 30.16764
 2005-May-29 00:00 *   0.002 4.039768 2.27074 6.25878 27.6043
 2005-Jun-28 00:00 *   0.002 4.07226 1.48117 5.97258 25.6162
 2005-Jul-28 00:00 *   0.002 4.091155 0.70061 5.80201 24.33219
 2005-Aug-27 00:00 *   0.002 4.096568 -0.07578 5.75274 23.78905
 2005-Sep-26 00:00 *   0.002 4.088531 -0.8526 5.82653 24.00853
 2005-Oct-26 00:00 *   0.002 4.066999 -1.63454 6.02069 25.02748
 2005-Nov-25 00:00 *   0.002 4.03184 -2.42645 6.32887 26.84076
 2005-Dec-25 00:00 *   0.002 3.982839 -3.23343 6.74308 29.30821
 2006-Jan-24 00:00 *   0.001 3.919684 -4.06125 7.25582 32.12539
 2006-Feb-23 00:00 *   0.001 3.841957 -4.91647 7.86159 34.88829
 2006-Mar-25 00:00 *   0.001 3.749117 -5.80671 8.55809 37.19117
 2006-Apr-24 00:00 *   0.001 3.64048 -6.7412 9.34693 38.69206
 2006-May-24 00:00 *   0.002 3.515183 -7.73127 10.23425 39.12172
 2006-Jun-23 00:00 * m 0.002 3.372145 -8.79122 11.23176 38.25779
 2006-Jul-23 00:00 * m 0.002 3.210002 -9.93984 12.35848 35.91333
 2006-Aug-22 00:00 * m 0.003 3.027011 -11.2025 13.64359 31.95139
 2006-Sep-21 00:00 * m 0.004 2.820913 -12.6147 15.13181 26.33289
 2006-Oct-21 00:00 * m 0.004 2.5887 -14.2287 16.89355 19.27516
 2006-Nov-20 00:00 *   0.004 2.326234 -16.125 19.04533 11.97245
 2006-Dec-20 00:00 *   0.003 2.027574 -18.4357 21.79619 10.29212
 2007-Jan-19 00:00 * m 0.003 1.683708 -21.3946 25.56936 18.59992
 2007-Feb-18 00:00 * m 0.003 1.280023 -25.4343 31.40271 30.70218
 2007-Mar-20 00:00 * m 0.004 0.793319 -30.8773 42.8547 45.50519
 2007-Apr-19 00:00 * m 0.008 0.339377 -1.20528 69.48386 54.3464
 2007-May-19 00:00 * m 0.013 0.782002 30.97835 43.23076 17.73441
 2007-Jun-18 00:00 * m 0.012 1.27067 25.53411 31.56493 16.62345
 2007-Jul-18 00:00 * m 0.01 1.675826 21.4659 25.66609 24.44062
 2007-Aug-17 00:00 * m 0.006 2.020762 18.4898 21.86346 31.95871
 2007-Sep-16 00:00 * m 0.004 2.320248 16.16829 19.09622 37.87983
 2007-Oct-16 00:00 * m 0.003 2.583379 14.26476 16.93408 41.88473
 2007-Nov-15 00:00 * m 0.002 2.816142 12.6456 15.16521 43.83286
 2007-Dec-15 00:00 * m 0.002 3.022708 11.22955 13.67177 43.72199
 2008-Jan-14 00:00 * m 0.002 3.206111 9.96393 12.3826 41.73745
 2008-Feb-13 00:00 * m 0.002 3.368629 8.81285 11.25254 38.2791
 2008-Mar-14 00:00 * m 0.001 3.51201 7.7507 10.25209 33.9383
 2008-Apr-13 00:00 * m 0.002 3.637623 6.75858 9.36204 29.43751
 2008-May-13 00:00 * m 0.002 3.746549 5.82214 8.57057 25.55104
 2008-Jun-12 00:00 * m 0.002 3.83965 4.93002 7.87147 22.98252
 2008-Jul-12 00:00 * m 0.002 3.917608 4.07305 7.26315 22.12119
*************************************************************************************************
Column meaning:
 
TIME
  Prior to 1962  times are UT1. Dates thereafter are UTC. Any 'b' symbol in
the 1st-column denotes a B.C. date. First-column blank (" ") denotes an A.D.
date. Calendar dates prior to 1582-Oct-15 are in the Julian calendar system.
Later calendar dates are in the Gregorian system.
  The uniform Coordinate Time scale is used internally. Conversion between
CT and the selected non-uniform UT output scale has not been determined for
UTC times after the next July or January 1st.  The last known leap-second
is used over any future interval.
  NOTE: "n.a." in output means quantity "not available" at the print-time.
 
SOLAR PRESENCE
  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
  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
 
 Ang-diam =
   The equatorial angular width of the target body full disk  if it were
fully visible to the observer.  Units: ARCSECONDS
 
 r       rdot =
   Target apparent heliocentric range ("r") and range-rate ("rdot") as seen
by observer. Units: AU and KM/S
 
 VmagSn VmagOb =
   Magnitude of target velocity wrt Sun ("VmagSn") and the observer ("VmagOb")
at time light left object to be observed (print time minus 1-way light-time).
Units: KM/S
 
 PsAng PsAMV =
   The position angles of the extended Sun->target radius vector ("PsAng")
and the negative of the target's heliocentric velocity vector ("PsAMV")
as seen in the observer's plane-of-sky  measured CCW from reference frame
North Celestial Pole. Small-bodies only. Units: DEGREES.
 
 PlAng =
   Angle between observer and target orbital plane  measured from center
of target at the moment light seen at observation time leaves the target.
Positive values indicate observer is above the object's orbital plane  in
the direction of reference frame +z axis. Small-bodies only. Units: DEGREES.
 Computations by ...
     Solar System Dynamics Group  Horizons On-Line Ephemeris System
     4800 Oak Grove Drive  Jet Propulsion Laboratory
     Pasadena  CA  91109   USA
     Information: http://ssd.jpl.nasa.gov/
     Connect    : telnet://ssd.jpl.nasa.gov:6775  (via browser)
                  telnet ssd.jpl.nasa.gov 6775    (via command-line)
     Author     : Jon.Giorgini@jpl.nasa.gov
*************************************************************************************************
</PRE>
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