T-square

Meaning

A T-square forms when two bodies in opposition are both square a third, which stands halfway between them, 90° from each. The shape is a T: the opposition is its crossbar, the third body its foot, the focal planet (often called the apex) where the tension of the opposition gathers.

It is one of the most dynamic figures a chart can hold. The ends of the opposition pull apart; the focal planet is pressed from both sides and becomes the place where the conflict looks for a way out. Much of the drive, ambition and restlessness associated with the figure comes from there: the focal planet is often over-used, a little forced, and also the source of real achievement.

As a rule the three bodies share a modality, which gives the T-square its style. A cardinal T-square acts and starts things; a fixed one persists and resists; a mutable one adapts, and can scatter.

Many astrologers also look at the empty corner, the point opposite the focal planet that would complete the shape into a cross. The sign and house there describe what the figure lacks, and what it can learn to develop as a release for its pressure.

In practice

• The Moon opposite Saturn, both square Mars: the tension between needs and duties is spent through Mars, in effort, sport or quick reactions. Learning to pace that energy is the figure’s work.
• The focal planet’s house shows where the pressure is spent; the house of the empty corner suggests where it can ease.
• A T-square that includes the Ascendant or the Midheaven ties the figure to the axis of self and others, or to the axis of public and private life.

Origin and history

Ptolemy names no such figure: in the Tetrabiblos (2nd century) he describes configurations between two signs at a time. Both aspects of the T-square are among those he calls discordant, the square and the opposition, because they join signs not of the same kind.

How Ulune calculates it

• Ulune looks for an opposition between two bodies and a third body square to both, with the birth chart’s orbs: 8° for each aspect.
• It searches among the ten planets, Chiron, the Ascendant and the Midheaven.
• The Table’s Patterns part names the third body as the focal one, with the range of orbs that hold the figure. When bodies in conjunction can stand in for one another, the shape is shown once, with its alternatives.
• A grand cross contains four T-squares; Ulune lists them after the cross.
• Ulune also picks a dominant configuration, the one with the most bodies and then the tightest orbs, and shows it under At a glance in the side panel. A T-square is often that figure.

Correspondences