What does Orb mean in celestial maps?

Orb (Western Astrology, Hellenistic): Latin: orbis — a circle, a disc, a sphere. In astrology it never means the planet's visible disc; it means the circle of effective influence drawn around its position. A term from celestial maps in the Pleroma Gnosis Lexicon.

What is the origin of Orb?

Latin: orbis — a circle, a disc, a sphere. In astrology it never means the planet's visible disc; it means the circle of effective influence drawn around its position

Orb — Definition & Meaning | Pleroma Gnosis Lexicon

Definition

An orb is the margin of degrees on either side of an exact aspect within which astrologers still count that aspect as working. It turns a geometric instant into a window: a planet nine degrees short of a natal point is already, on the traditional rule, in contact with it.

Primary source

That distance round a planet to which its influence more particularly extends.

— An Introduction to Astrology, by William Lilly, with numerous emendations by Zadkiel (H. G. Bohn, London, 1852), Appendix glossary, s.v. Orb, p. 343. Open-access copy

Deep Understanding

Without an orb, astrology would have almost nothing to say. An exact aspect is an instant, and instants cannot be lived through. The orb is the device that makes a transit into a season.

The traditional rule assigns the orb to the planet rather than to the aspect. Lilly's book gives Saturn nine degrees before and after, and the influence is counted from the moment either body comes within half of nine degrees added to half the other planet's orb. That halving is called the moiety, and it means two slow planets carry a wider shared window than a slow planet and a fast one.

Modern practice went the other way. Most contemporary astrologers assign the orb to the aspect, not the planet, and use far tighter figures for a transit: one to three degrees is common where Lilly used nine. Nobody arbitrates between the two, which is worth saying plainly. There is no measured orb. It is a convention, and the conventions disagree by a factor of four.

That is also why the duration questions people ask about transits have no single answer. Ask how long a transit lasts and the honest reply is a question back: at whose orb? Degrees are fixed and time is not, because a planet's apparent speed changes across its cycle and reverses altogether when it goes retrograde.

Often confused with

Planetary aspects: the angles themselves, where an orb is the tolerance around one of them. Transits: the moving-planet contacts an orb measures, not the measure. Houses: the chart sectors, which carry their own five-degree orb at the cusp in the same book.

In Practice

The orb is a teaching about anticipation before it is a technical term, and you can test that part tonight without a chart. Sit for ten minutes and write down what you are currently braced for. Not what has happened: what you are holding yourself ready for. Most of what surfaces will be an approach rather than an arrival, and it will have been shaping your week already. That is the applying aspect, felt from the inside. The pressure arrives before the event because you arrive at it first.

In Pleroma's Words

Nothing in you waits for exactness. You begin paying for the conjunction nine degrees out, and you are still paying for it nine degrees past.

@online{alkimia2026orb, author = {{Stefan's Alkimia}}, title = {{Orb}}, organization = {{Pleroma Guide}}, date = {2026-11-02}, year = {2026}, url = {https://pleroma.guide/en/lexicon/orb}, langid = {english} }

Orb