Heliocentric Ephemeris Study
A heliocentric ephemeris study generates a tabular listing of planetary positions as observed from the Sun. Heliocentric positions show true orbital positions without Earth's motion influencing the results, making them useful for studying planetary orbits and cycles.
Creating a Heliocentric Ephemeris Study
- Click the Heliocentric Ephemeris toolbar button or select Ephemerides > Heliocentric Ephemeris from the menu.
A new study appears in the studies list panel and the study content area shows its configuration. The coordinate origin is fixed to Heliocentric.
Configuring the Study
The configuration parameters are identical to the Geocentric Ephemeris Study, including study name, location, zodiac system, reference plane, date range, interval, body selection, and metric selection.
A location is required even for heliocentric ephemerides because Ephy calculates and displays date and time values according to the selected location's time zone.
Zodiac System
Select a zodiac system from the Zodiac System dropdown:
| Option | Description |
|---|---|
| Tropical | Based on the vernal equinox |
| Sidereal | Based on fixed star positions |
Reference Plane
Select a reference plane from the Reference Plane dropdown:
| Option | Description |
|---|---|
| Ecliptic | Positions measured relative to the ecliptic plane |
| Equatorial | Positions measured relative to the celestial equator |
Time Unit
Select the interval time unit from the Time Unit dropdown:
| Option |
|---|
| Hours |
| Days |
| Months |
| Years |
Available Bodies
The heliocentric ephemeris study includes a different set of bodies than the geocentric study. Since observations originate from the Sun, the body list excludes the Sun itself and replaces the Moon with Earth. Lunar axis points are not available.
| Body | Type |
|---|---|
| Mercury | Planet |
| Venus | Planet |
| Earth | Planet |
| Mars | Planet |
| Jupiter | Planet |
| Saturn | Planet |
| Uranus | Planet |
| Neptune | Planet |
| Pluto | Planet |
| Tenet | Smaller Body |
| Vesta | Smaller Body |
| Juno | Smaller Body |
| Ceres | Smaller Body |
| Pallas | Smaller Body |
| Chiron | Smaller Body |
| Pholus | Smaller Body |
Generating the Ephemeris
After configuring all parameters, click the Run button to generate the ephemeris. See Generate Ephemeris Records for details.