Reference · Astrology
What is a grand cross?
Kevin Blaxton — software builder; astrology student for 40+ years · figures computed by the OrbHeaven engine
Published · Last revised
A grand cross is four planets forming two oppositions that cross at right angles, so every neighbouring pair is a square. It reads as two interlocked T-squares, and the tradition takes it as four-way tension that asks for balance across every side at once.
What is a grand cross?
Geometrically it is four points at 0°, 90°, 180° and 270° — two oppositions at right angles, which makes four squares around the figure. The figure shows the shape and names its aspects, read from the engine: two oppositions and four squares in all.
The four planets usually share a modality — all cardinal, all fixed or all mutable — because signs 90° and 180° apart do, which gives the cross its characteristic flavour.
Which configurations qualify
All six aspects must hold within orb: two oppositions (within 8°) and four squares (within 7°), one degree more with the Sun or Moon. A worked example: planets at 15° Taurus, 15° Leo, 15° Scorpio and 15° Aquarius — a fixed grand cross, with the Taurus–Scorpio and Leo–Aquarius oppositions squared all round. If one square falls out of orb, it is not a complete grand cross but two T-squares or an incomplete figure.
What it is read as
Interpretation, labelled as such: the grand cross is read as the most demanding of the common figures — four planets in constant mutual tension, pulling in four directions, which asks for balance on every side at once. The tradition also reads it, worked with, as a source of real endurance and drive.
A short history
Its parts — the square and opposition — are classical Ptolemaic configurations, but the grand cross as a named four-planet figure belongs to the modern study of aspect patterns, where it is treated as a pair of linked T-squares and classed by its shared modality (cardinal, fixed or mutable).
Common misconceptions
- Is a grand cross just two T-squares?
- It can be read as two interlocked T-squares — but it requires all four planets in two oppositions that also square each other, so both T-squares are completed by the same four planets.
- Does a grand cross have an apex like a T-square?
- No single apex — the tension is spread across all four planets at once, which is why it is read as asking for balance on every side rather than a single focus.
References & further reading
- [1] Ptolemy, Tetrabiblos (2nd c. CE) — the square and opposition among the classical configurations.
- [2] Tierney, B., Dynamics of Aspect Analysis — the grand cross and modality-based configuration analysis.
- [3] OrbHeaven engine (astronomy-engine), aspects module — the 90°/180° angles and orbs; the shape’s two oppositions and four squares re-derived in chart-shapes.test.ts.
Suggested citation
Blaxton, K. (2026). What is a grand cross. OrbHeaven Reference. https://orbheaven.com/reference/the-grand-crossRevision history
- First build (concise). Shared chart-shape diagram (two oppositions + four squares, engine-classified); worked example (fixed grand cross in Taurus/Leo/Scorpio/Aquarius). Qualification by orb and the “two interlocked T-squares” reading; links up to Aspects, The Opposition and The Square. No photo, no interactive.
Related glossary entries
About a minute. Birth time optional, and no account until after you have seen it.
More in the reference library
What is an aspect in astrology? The angles, the orbs, and the geometry
An aspect is the angle between two points in a chart. This is the geometry — the six angles astrologers use, what an orb is, and where the set comes from — with an interactive dial that classifies any separation using OrbHeaven’s engine.
What is an opposition?
An opposition is two planets 180° apart, facing each other across the chart. This explains the geometry, how OrbHeaven counts it within an 8° orb, what the tradition reads into it, and where it comes from.
What is a square in astrology?
A square is two planets 90° apart — a quarter of the circle, three signs apart, in signs of the same modality. This explains the geometry, how OrbHeaven counts it within a 7° orb, what the tradition reads into it, and where it comes from.