Earth Ephemeris: Daily Heliocentric Trajectories in Multiple Coordinate Systems

HelioWeb provides daily heliocentric trajectory data for Earth, calculated in Heliographic (HG), Heliographic Inertial (HGI), and Solar Ecliptic (SE) coordinate systems. The data originates from NASA's JPL Horizons system and uses the 'Mean of Date' method for the Equinox Epoch. The dataset was last updated on March 13, 2026.

Use Cases

• Modeling spacecraft ephemeris near Earth based on the description that planet orbit data can serve as a proxy.
• Analyzing solar wind propagation based on heliocentric longitude differences mentioned for spacecraft at the L1 Lagrange point.
• Comparing coordinate transformations between Heliographic, Heliographic Inertial, and Solar Ecliptic systems.
• Studying the drift of the First Point of Aries (FPA) based on the described methods (B1950.0, J2000.0, True of Date, Mean of Date).

Strengths

• Data is sourced from NASA's authoritative JPL Horizons system.
• Coordinates are calculated using the specific 'Mean of Date' method for the Equinox Epoch.
• Includes multiple coordinate systems (HG, HGI, SE) for trajectory analysis.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Description metadata is limited; actual data quality requires manual inspection after download.

Provenance

Source

National Aeronautics and Space Administration (NASA), JPL Horizons system.

Collection Method

Calculated from original trajectory data obtained from http://ssd.jpl.nasa.gov/horizons.cgi.

Time Range

Daily data; specific temporal coverage is not stated.

Freshness

Last updated 2026-03-13 07:43:03.831618; freshness should be verified.

Geography

Heliocentric (solar system) scale.