Nodal Transits Study
A body sitting exactly on the ecliptic is a condition declination workers track in its own right, and that is what a nodal transit is. The Nodal Transits study dates every one of those crossings for the bodies you follow.
The study generates an event each time a selected body transits its own ascending or descending node, the moment its latitude crosses zero. Each event carries the body's position and motion at the crossing.
Create a Nodal Transits Study
To add a Nodal Transits study to the current workspace:
- Click Mundane Studies → Declination Studies on the menu bar.
- Click Nodal Transits in the Declination Studies submenu.
Alternatively, click the Declination Studies drop-down button on the toolbar and select Nodal Transits from its flyout.
The new study appears at the bottom of the Studies list and is selected automatically, so its settings open immediately. It takes its name from the study type.
What This Study Finds
A nodal transit is the moment a body crosses one of its own nodes, the two points at which its latitude passes through zero. The study watches each body you check and records the instant of every ascending and descending crossing in the date range.
Its settings carry an Event Type drop-down, which restricts the study to ascending crossings or to descending crossings, and a single Bodies selection list. Because the technique depends on latitude, neither the diurnal angles nor the hypothetical Uranian bodies are offered in that list. See Which Bodies a Study Offers for the full set a study omits.
Events Table Columns
The events table lists one row per nodal transit. Several columns are hidden by default, as the table notes. Right-click any column header to show or hide a column, as described in Choose Events Table Columns. The header text of the coordinate columns follows the study's Reference Plane: they read Longitude and Latitude in the ecliptic plane and Right Asc and Declination in the equatorial plane. The table below uses the ecliptic-plane headers.
| Column | Description |
|---|---|
| Date Time | Date and time the event perfects, in the application's long date-time format. Always the first column, and it cannot be moved. Visible by default. |
| Event Type | Which kind of crossing the event records, an ascending node transit or a descending node transit. Visible by default. |
| Body | Name of the celestial body. Visible by default. |
| Body Longitude | The body's primary coordinate in degrees. Hidden by default. |
| Body Sign | The body's position as degrees, sign and minutes of the zodiac. Visible by default. |
| Body Latitude | The body's secondary coordinate in degrees. Hidden by default. |
| Body Distance | The body's radial distance in astronomical units (AU). Hidden by default. |
| Body Speed | The body's speed in degrees per day. Hidden by default. |
| Event Interval | Elapsed time since the previous event in the list. Hidden by default. |