ADC/CDS Standard Document for Catalog:
/external/astrom/E1004/

E/I/4                      JPL's HORIZONS System      (Giorgini+ 1996)
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JPL HORIZONS On-Line Solar System Data and Ephemeris Computation Service
    Giorgini J.D., Yeomans D.K., Chamberlin A.B., Chodas P.W.,
    Jacobson R.A., Keesey M.S., Lieske J.H., Ostro S.J., Standish E.M., 
    Wimberly R.N.
    <Bull. Am. Astron. Soc., 28(3), 1158, (1996)>
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ADC_Keywords: Ephemerides; External catalog

Location: http://ssd.jpl.nasa.gov/horizons.html

Description:
   The JPL Horizons On-Line Ephemeris System provides easy access to key solar 
   system data and flexible production of highly accurate ephemerides for 
   solar system objects. This includes 71000+ asteroids & comets, 63 natural 
   satellites, 9 planets, the Sun, spacecraft, and several dynamical points. 
   Users may also define their own objects, then use the system to integrate 
   the trajectory, or conduct parameter searches of the comet/asteroid 
   database, searching on combinations of up to 40 different parameters. Rise, 
   transit and set may be identified to the nearest minute. 

   More than 70 different observational and physical aspect quantities can be 
   requested at intervals for both topocentric and geocentric situations in 
   one of 9 coordinate systems and 4 time scales (TDB, TT, UT, Civil). Over 
   600 Earth station locations are on file; users can input their own 
   topocentric coordinates if not listed. Output is suitable for observers, 
   mission planners and other researchers although this determination is 
   ultimately the users' responsibility. 

   Four types of customizable output can be requested: 

      1.Observables (RA/DEC, Az/El, physical aspect, angles, etc.) 
      2.Osculating elements 
      3.Cartesian state vectors 
      4.SPK binaries (asteroids and comets only) 

   The first three are ASCII tables. Output is returned to the user via e-mail, 
   FTP or Kermit protocols. Table output can be requested in a format suitable
   for spreadsheet import. SPK file output allows user programs to reproduce 
   the integrated target state at any instant. The SPK files can be used by 
   existing visualization, animation and mission-design software. 

   The underlying planet/satellite ephemerides and small-body osculating 
   elements are the same ones used at JPL for radar astronomy, mission 
   planning and spacecraft navigation. 

Acknowledgements:
   This software reflects the underlying contributions of several people at 
   JPL: 

     Design/implementation : Jon Giorgini 
                             Don Yeomans
    
     Cognizant Eng.        : Jon Giorgini

     Ephemerides           : Myles Standish (Planetary ephemerides)
                             Bob Jacobson   (Satellites)
                             Jay Lieske     (Satellites)

     Contributors          : Paul Chodas 
                             The NAIF group (SPICELIB & donated computer)
                              (esp. Chuck Acton, Bill Taber, Nat Bachman) 
                             Ray Wimberly
                             Mike Keesey
                             Alan Chamberlin   


References:
     Giorgini, J.D., Yeomans, D.K., Chamberlin, A.B., Chodas, P.W., 
     Jacobson, R.A., Keesey, M.S., Lieske, J.H., Ostro, S.J., Standish, E.M., 
     Wimberly, R.N., "JPL's On-Line Solar System Data Service", American 
     Astronomical Society, DPS meeting #28, #25.04 (1996) =1996DPS....28.2504G

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(End)                         Gail L. Schneider [SSDOO/ADC]      9-Oct-1998