Geocentric Ephemeris Study
A geocentric ephemeris study generates a tabular listing of planetary positions as observed from Earth's center. Geocentric coordinates are the most commonly used perspective in traditional astrology, representing where celestial bodies appear in the sky relative to Earth.
Creating a Geocentric Ephemeris Study
- Click the Geocentric Ephemeris toolbar button or select Ephemerides > Geocentric 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 Geocentric.
Configuring the Study
The left panel of the study view contains all configuration parameters. Each new study inherits its default parameter values from the current Workspace Defaults.
Study Name
Enter a descriptive name in the Name field at the top of the study view to help you identify this study in the studies list.
Location
Select a geographic location from the Location dropdown. The list contains locations managed through the Locations Editor.
A location is required for all ephemeris types 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 (0 degrees Aries = March equinox point) |
| 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 |
Changing the reference plane also updates the display names of the metrics. When set to Ecliptic, the metrics are Longitude and Latitude. When set to Equatorial, they change to Right Asc and Declination.
Date Range and Interval
Configure the time span and interval for the ephemeris:
- Start Date — The beginning date for the ephemeris.
- Start Time — The starting time of day.
- End Date — The ending date for the ephemeris.
- Interval — The numeric value for the time step between records.
- Time Unit — The unit for the interval: Hours, Days, Months, or Years.
Bodies and Metrics
Below the date range parameters, the study view displays two lists:
- Bodies — Select which celestial bodies to include. See Body Selection for details.
- Metrics — Select which positional metrics to display. See Metric Selection for details.
Available Bodies
The geocentric ephemeris study includes the following celestial bodies:
| Body | Type |
|---|---|
| Moon | Planet |
| Mercury | Planet |
| Venus | Planet |
| Sun | Planet |
| Mars | Planet |
| Jupiter | Planet |
| Saturn | Planet |
| Uranus | Planet |
| Neptune | Planet |
| Pluto | Planet |
| Tenet | Smaller Body |
| Lunar Apogee | Lunar Axis |
| Mean Apogee | Lunar Axis |
| North Node | Lunar Axis |
| Mean Node | Lunar Axis |
| 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 on the generation process, progress tracking, and cancellation.
