The ISO Satellite & General Instrumentation Page

Generation of ISO-centered observation ephemerides for solar system targets

The "HORIZONS On-Line Ephemeris System" provides easy access to key solar system data and flexible production of highly accurate ephemerides for solar system objects.

The ISO trajectory is publicly accessible from HORIZONS now (telnet or e-mail access only, not yet in the web interface). This allows you to generate ISO-centered observation ephemerides for any solar system target, geometric cartesian states vectors for ISO or orbital elements for ISO at any time/ period during the ISO mission (see examples below).

The telnet interface accesses all programme functions, including allowing ISO-centered coordinate systems.

Primary functional link (launches programme):

             (or telnet 6775)

Other links you may want to consider:

Descriptive introductory link:
Documentation links (indexed HTML and PostScript-download forms):

Thomas Müller & Alberto Salama, ISO Data Centre, 8 August 2000

Worked Examples:

  1) ISO-centric ephemerides for asteroid (4) Vesta

  telnet 6775
  Horizons> Vesta;
  Select... [E]phemeris, [F]tp, [K]ermit, [M]ail, [R]edisplay, [S]PK : e
  Observe, Elements, Vectors  [o,e,v,?] : o
  Coordinate center [ ,coord,geo  ] : @iso
  Starting UT  [ex: 1995-Nov-17 01:54 ] : 1997-Apr-28 02:03
  Ending   UT  [ex: 1998-Jul-16 01:43 ] : 1997-Apr-28 04:05
  Output interval [ex: 10m, 1h, 1d, ? ] : 10m
  Accept default output [ cr=(y), n, ?] : 
  Select table quantities [ <#,#..>, ?] : 1,19,20
  Select... [A]gain, [N]ew-case, [F]tp, [K]ermit, [M]ail, [R]edisplay : q

  2) ISO Geometric cartesian states in Geocentric Frame (X,Y,Z,VX,VY,VZ)

  Horizons> ISO
  Select... [E]phemeris, [F]tp, [K]ermit, [M]ail, [R]edisplay, ?, : e
  Observe, Elements, Vectors  [o,e,v,?] : v
  Coordinate center [ ,coord,geo  ] : geo
  Reference plane [eclip, frame, body ] : eclip
  Starting TDB [ex: 1995-Nov-17 01:55 ] : 1997-Apr-28 02:03
  Ending   TDB [ex: 1998-Jul-16 01:44 ] : 1997-Apr-28 04:05
  Output interval [ex: 10m, 1h, 1d, ? ] : 10m
  Accept default output [ cr=(y), n, ?] : 
  Select... [A]gain, [N]ew-case, [F]tp, [K]ermit, [M]ail, [R]edisplay : q


  We would like to thank Jon Giorgini, JPL, for his support and for
  implementing the ISO orbit file and Nat Bachman, JPL, for the 
  conversion of the ISO trajectory file and the SPK extensions.
  Computations by:
     Solar System Dynamics Group, Horizons On-Line Ephemeris System
     4800 Oak Grove Drive, Jet Propulsion Laboratory
     Pasadena, CA  91109   USA
     connect    : telnet://  (via browser)
                  telnet 6775    (via command-line)
     e-mail     :