Is a stellium three planets or four?

There is no universal rule. This calculator discloses and applies a three-or-more threshold under two separate definitions.

Do the Sun and Moon count in a stellium?

They do here, alongside Mercury through Pluto. Angles, nodes and asteroids are excluded and the rule is shown beside the result.

No. The form has no submission endpoint; the astronomical calculation runs locally in your browser.

birth chart · concentrated planets · two disclosed definitions

Stellium Calculator: Find Chart Clusters

Check whether three or more natal planets gather in one zodiac sign or inside a tight 10° arc. Because astrologers do not share one universal definition, the calculator reports both rules instead of silently choosing one.

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What counts as a stellium here

Sign rule

Three or more of the ten planets occupy the same 30° zodiac sign.

Tight-cluster rule

Three or more planets fit inside one 10° arc, even if the arc crosses a sign boundary.

Included points

Sun, Moon and Mercury through Pluto count. Ascendant, Midheaven, nodes and asteroids do not.

A cluster is emphasis, not a verdict

A stellium can make one sign, element or set of planetary functions visually prominent in a chart, but quantity alone does not say whether that concentration feels easy. The planets involved, their exact aspects and the rest of the chart change the reading. Not finding a stellium does not make a chart weak or uninteresting; most charts do not need one to have clear patterns.