Ephemeris Settings
The ephemeris settings anchor a study to a geographic location and define its reference system. These settings appear near the top of every study type.
To set a study's ephemeris settings:
- Select a location from the Location dropdown.
- Select a zodiac system from the Zodiac dropdown.
- Select a reference plane from the Ref. Plane dropdown.
Location
The Location dropdown lists the geographic locations in your shared locations library. A location is required for every study type, including geocentric and heliocentric studies, because each record's date and time are shown in the location's time zone. Without a location, an ephemeris cannot be generated.
To add, edit, or remove locations, use the Locations Editor.
Reference System
The zodiac, the reference plane, and the study's coordinate origin together make up the study's reference system. The coordinate origin (geocentric, topocentric, or heliocentric) is fixed by the study type you create. You choose the zodiac and reference plane here.
Zodiac
| Zodiac System | Description |
|---|---|
| Tropical | Positions are measured from the vernal equinox. |
| Sidereal | Positions are measured against the fixed stars. |
Reference Plane
| Reference Plane | Description |
|---|---|
| Ecliptic | Positions are referenced to the plane of the ecliptic. |
| Equatorial | Positions are referenced to the celestial equator. |
The reference plane also affects how body-position columns are labeled in the ephemeris table. See Body Metrics List.
Ephemeris Presets
A presets button sits beside the Location dropdown. Use it to apply a saved combination of location and reference-system settings, or to save the current settings as a preset. See Ephemeris Presets.