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Planetary Observational Data

The creation of modern ephemerides involves the fitting to a wide variety of astronomical measurements (observations). This page presents the sets of observations that are currently being used in the creation and improvement of modern planetary and lunar ephemerides.

These data are currently maintained by Ryan Park; JPL/Caltech (

Meridian Circle Timings (transits)

Photographic Astrometry of Outer Planets and Satellites

Photographic Astrometry of Pluto

CCD Astrometry of Outer Planets and Satellites

Astrolabe Observations

Radar Ranging from Eupatoria, Crimea

Radar Ranging from Goldstone, California

  • Mercury, 1967-97
  • Venus, 1967-90

Spacecraft Encounter Estimates

Right ascension, declination and range estimates from spacecraft encounters with tracking data (Doppler, range, and VLBI) re-reduced in ICRF frame.

Spacecraft VLBI

Data from Magellan, Venus Express at Venus, Phobos, Mars Global Surveyor, Odyssey, Mars Reconnaisance Orbiter at Mars, and Galileo at Jupiter.

Mercury Spacecraft Range

Venus Spacecraft Doppler

Mars Spacecraft Ranging

Mars Spacecraft Doppler (Differenced Range)

Juno Spacecraft Range

Cassini Spacecraft Range

DSN Station Locations

Lunar Laser Ranging

These data are provided by the International Laser Ranging Service.