← Encyclopedia of Astrology · lesson 165/235
Stellium
The shape
A stellium is a cluster: three or more planets in the same sign, or three or more in the same house. Unlike every other figure in this section it is not built from aspects at all. It is read from positions — which sign and which house each planet stands in — so it is found even when the planets are spread across the sign and do not all make a conjunction with one another.
A worked example: Venus at 2° Virgo, Mercury at 14° Virgo and the Sun at 27° Virgo make a stellium in Virgo. Venus and the Sun are 25° apart, too far for a conjunction, but all three share the sign. If they also fell in one house, the chart would show a sign stellium and a house stellium over the same planets.
Only the ten planets count here; the nodes, Chiron and the angles do not make up the numbers. Some astrologers ask for four planets, or five when the Sun, Mercury and Venus are involved (they are never far apart); this entry describes the three-planet threshold the chart uses.
What it is made of
Planets, not aspects. Because a stellium is positional, it sits outside the way other figures contain one another: four planets in Leo can also form part of a Grand Cross, and the chart reports both, because "these planets share a sign" and "these planets form a cross" are two different statements.
No apex
There is no apex. What matters is the sign, its element and mode, the house, and what each planet brings to the gathering. Steven Forrest calls it an unmistakable concentration of energy: with only ten planets to share among twelve signs and twelve houses, three in one place is an emphasis.
By sign and house
A sign stellium colours the temperament with that sign's qualities; a house stellium points to the area of life where much of the energy goes. The sign or house opposite is often read as relatively neglected — the stellium's blind side.
In a chart
A natal stellium tends to show single-mindedness: real gifts and drive in its area, and a matching risk of narrowness. It is the most common configuration of all, which is why every chart display shows it.
In the sky
Planets bunch together in the passing sky too, and several transiting planets moving through one sign can turn attention strongly to the matters of that sign, or to the natal house it occupies, for as long as they stay.