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Topocentric Aspect Ephemeris Study

A topocentric aspect ephemeris study records positions as observed from a specific point on the Earth's surface, together with the angular relationships between pairs of bodies, sampled at a fixed interval across a date range. It gives you observer-relative aspect data: angles computed from the positions as seen from the place you chose.

Bodies are chosen in two lists, Inner Bodies (the aspecting set) and Outer Bodies (the aspected set), and every valid pairing between the two lists contributes its own aspect columns to the ephemeris table.

A Topocentric Aspect Ephemeris Study for New York, with Venus/Mars aspect columns in its ephemeris table.

The Two Tabs​

The settings column carries two tabs:

Create and Generate the Study​

To produce a topocentric aspect ephemeris:

  1. Click Ephemerides → Topocentric Aspect Ephemeris on the menu bar.
  2. Configure the Basic Ephemeris Settings (Location, Zodiac, Ref. Plane) and the Ephemeris Date Range (Start Date, Start Time, End Date, Interval, Time Unit).
  3. On the Inner & Outer Bodies tab, check the bodies in the Inner Bodies and Outer Bodies lists.
  4. On the Body & Aspect Metrics tab, check the metrics in the Body Metrics and Aspect Metrics lists.
  5. Click the Run button beneath the ephemeris table.

A Topocentric Aspect Ephemeris Study with the Moon checked in the Inner Bodies list and Saturn in the Outer Bodies list.

Step 1 is performed on the Ephemerides menu:

The Ephemerides menu with Topocentric Aspect Ephemeris highlighted between the Geocentric and Heliocentric Aspect entries.

An Interval of 1 with a Time Unit of Days gives one record per day.

caution

The location matters twice here. It fixes the observing point the positions are computed for, and it fixes the time zone each record is dated in. Check its coordinates and height in the Locations Editor before you generate.

Bodies​

The Inner Bodies list offers the full 33-body Earth-frame catalog, including the Diurnal Angles group, so an angle such as the Ascendant, computed for your observing point, can take part in the aspect pairs. The Outer Bodies list omits those four angles and offers the remaining 29 bodies, so an angle can be the aspecting (inner) member only. See Bodies List.

Measurements​

Two metrics lists share the Body & Aspect Metrics tab.

The Body Metrics list adds positional columns for every selected Inner and Outer body: Longitude, Sign Position, Latitude, Distance in AU, and Speed in degrees per day. Under an Equatorial reference plane the first and third read Right Asc and Declination. On a new aspect study only Sign Position is checked.

The Aspect Metrics list adds relationship columns for every valid body pair.

Aspect metricWhat it reports
Cycle AngleThe angular distance from the outer body to the inner body in the direction of zodiacal motion, from 0 to 360 degrees.
PhaseWhere the pair sits in its cycle: New, Waxing, Full, or Waning.
SeparationThe shortest angular distance between the two bodies regardless of direction, from 0 to 180 degrees.

Phase and Separation are checked by default on a new aspect study.

note

These three metrics are the only aspect-related list in Cygnus. There is no editable list of aspect angles or aspect values anywhere in the application.

After the Records Are Generated​

The study locks when the generation completes, and the Run button becomes invisible until you unlock the study. Meanwhile you can read, arrange, search, copy, and export the results: