Topocentric Ephemeris

A topocentric ephemeris study generates a tabular listing of planetary positions as seen from a specific geographic location on Earth's surface at regular time intervals. This perspective accounts for the observer's exact position, applying parallax corrections to produce the most location-accurate positions.

Creating a Topocentric Ephemeris Study

Using the Menu

1. Click Ephemerides on the menu bar.
2. Click Topocentric Ephemeris in the Ephemerides menu.

Using the Toolbar

• Click the Topocentric Ephemeris toolbar button.

A new topocentric ephemeris study is added to the studies list and automatically selected.

Configuring the Study

The configuration panel for a topocentric ephemeris study contains the following settings:

Study Name

Each study has an editable name that appears in the studies list. You can change the name to describe the purpose of the study.

Location

Select a geographic location from the Location dropdown. For topocentric studies, the location is especially important as it determines both the time zone for date display and the observer position used in parallax corrections. Locations are managed through the Locations Editor.

Zodiac System

Select the zodiac system from the Zodiac dropdown:

Option	Description
Tropical	Positions measured from the vernal equinox point
Sidereal	Positions measured from a fixed star reference

Reference Plane

Select the reference plane from the Reference Plane dropdown:

Option	Description
Ecliptic	Positions measured along the ecliptic plane
Equatorial	Positions measured along the celestial equator

Date Range

Set the Start Date and End Date to define the time span for the ephemeris.

Time Interval

Configure the time interval between records by setting the Interval value and selecting a Time Unit from the dropdown:

Time Unit
Seconds
Minutes
Hours
Days
Months
Years

Bodies

Select the celestial bodies to include using the Bodies list. The topocentric body list is identical to the geocentric body list, including: Ascendant, Medium Coeli, Descendant, Imum Coeli, Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, Tenet, Lunar Apogee, Mean Apogee, North Node, Mean Node, Vesta, Juno, Ceres, Pallas, Chiron, and Pholus.

See Body Selection for details on selecting and deselecting bodies.

Metrics

Select the metrics to include as columns in the ephemeris table using the Metrics list. See Ephemeris Metrics for details.

Generating the Ephemeris

Once all parameters are configured, generate the ephemeris by clicking the Run button. See Generating Records for details on generation, cancellation, and unlocking.

Working with Results

After generation completes, the ephemeris table displays the results. You can:

• Navigate to specific dates in the results
• Manage column visibility and order
• Export data to CSV or copy to clipboard

tip

Save study configurations as ephemeris presets to quickly apply the same settings to new studies.