Stellium: A Cluster of Planets in the Birth Chart

This grouping indicates power, possibly even genius

Stars
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A stellium is a bundle of three or more planets in the birth chart. They combine to form a kind of super planet, acting as one force. With this pattern, the planets are all in the same zodiac sign. It's often said that we have all 12 zodiac signs in our nature, but a strong stellium packs the most punch. 

A stellium is a highly charged hot zone of your birth chart. You favor these energies, and others sense them. If it's powerful enough, it outshines your Sun sign as the most outstanding constellation of traits. 

Mozart's Stellium

Wolfgang Amadeus Mozart had a stellium of Saturn, the Sun, and Mercury in Aquarius. If genius is a sustained channel to the divine mind, he had that with a concentration of planets including Mercury in visionary Aquarius.

A stellium with the wow factor involves personal planets, such as the Sun, Moon, Mercury, Mars, and Venus. If your personal planets are grouped with the slow-moving outer planets, you have an affinity for your generation's mission or the climate of the times.

Stella is the Latin word for stars. Stellia, the plural word for clusters, are easy to spot in the birth chart.

Astrologers vary on how close in distance some aspect patterns should be to constitute a stellium. Some say 1 or 2 degrees, while others allow up to 5 degrees.

But with the stellium, a more sweeping orb is allowed, as long as they're in the same zodiac sign. The closer the planets are, the greater the potency.

Many times the planets are in the same house, but not always. It's more challenging to interpret charts where the stellium lies over a cusp, the dividing line between two houses. The most striking stellium—and easiest to see at play—are close in orb and in the same house. 

But planets in the same house in different Zodiac signs are not considered a stellium. 

The Pattern Tells the Story

Donna Cunningham's ebook "The Stellium Handbook" is about this pattern. Writes Donna

"What makes you different is the cast of recurring characters—or their types—and the repeated story arcs....Explore the story that keeps replaying itself and that cast of characters. It may have minor variations but so often works out the same as the last few times."

Her main thesis is that the "sequence of planets in the stellium...tells the story." The lead planet (of lowest degree) is like a "first responder," setting the stage for what follows.

"If it [the lead planet] were Saturn, you might react fearfully and close down while you figure out how to protect yourself. Suppose Mars is the lead planet. It represents the urge to be first, to be a pioneer, to lead, and to win. It's happiest as the lead planet, but aggressive outreach isn't always an ideal approach."

Striking a Balance

Astrologer Kevin Burk writes that a key issue with the stellium is balance. In "Understanding the Birth Chart," he writes that a transit opposite your stellium gives you that chance to find balance. You may also have an opposition in your birth chart that emphasizes the dance between polarities.