Midpoint cluster

Meaning

A midpoint cluster is a place on the dial where several midpoints fall within a degree or so of one another. Each midpoint joins a pair of planets; when three, four or more of them land on the same spot, that spot links several different pairs at once. Any planet or angle standing there takes part in all of those planetary pictures together. If no planet stands there, the spot is still treated as sensitive, waiting to be set off.

The easiest way to find clusters is to read down a midpoint sort and look for stretches where the entries crowd together.

Origin and history

The underlying idea is old in midpoint work. Alfred Witte and the Hamburg School, and later Reinhold Ebertin's cosmobiology, read whole groups of planets in symmetrical arrangement together; Howe describes Hamburg School equations with a dozen or more planetary combinations in a single line [3]. Ebertin's Applied Cosmobiology speaks of clusters of factors on the 90° circle, meaning planets and angles bunched together there, which are therefore in hard aspect to one another (p. 16) [4]. Treating a bunch of midpoints itself as a named object is a matter of modern practice.

"Midpoint cluster" is a descriptive phrase rather than a term with one agreed definition, and authors and programs use it differently. One may mean any group of midpoints within an orb of a single point; another may require the group to be chained, each midpoint close to the next; some count planets as members, others only midpoints. Book-length English treatments of midpoints include Harding and Harvey's Working with Astrology (1990) [1] and Munkasey's Midpoints (1991) [2].

How it is used

As a sensitive zone. A cluster marks a degree area (on the 90° dial, the same degree in all four cardinal, fixed or mutable signs at once) where several themes of the chart meet. Astrologers look at which pairs are involved: a cluster made of pairs that share a planet repeats that planet's theme; a cluster of unrelated pairs ties those themes together.

Occupied or empty. If a planet or angle sits in the cluster, it becomes a focus for all the pairs, much like a crowded branch of a midpoint tree. If nothing sits there, the cluster is latent.

Timing. Clusters are especially watched for timing. When a transiting planet, or a planet moved by a direction such as the solar arc, reaches the cluster's dial degree, it contacts every midpoint in it within a short span. Because on the 90° dial one degree stands for four places in the zodiac (and their squares and oppositions), the same cluster is reached several times as a slow planet moves around the circle.

Tight orbs. Clusters are defined with small orbs (Ebertin allows 1½° for a single midpoint contact and about 1° in timing, pp. 23, 69, 107 [4]), since with 45 to 91 midpoints on a 90° dial some bunching happens by chance: with 45 midpoints the average gap between neighbours is only 2°. A cluster whose spread is under a degree is more notable than a loose chain over several degrees.

On this site. The Midpoints panel's Clusters view lists groups of three or more midpoints chained together, each within 1° of the next on the chosen dial (90° by default; 45°, 360° and 22.5° are options). Because the rule is a chain, a cluster can spread over more than 1° in total; the panel shows its centre and spread. Any planet or angle lying inside the cluster, or within 1° of either end, is listed with it. The points used are the ten planets, the Moon's Node, the Ascendant and Midheaven (only with a known birth time) and, if switched on, the Aries Point. Midpoints are shorter-arc midpoints, and positions are folded onto the dial as longitude modulo the dial. The site does not use the Hamburg School's hypothetical points.

Examples

Albert Einstein (14 March 1879, 11:30 local mean time, Ulm), ten planets only, 90° dial, using the site's rule (three or more midpoints each within 1° of the next). Five clusters appear:

• A long occupied chain. The first cluster spreads over about 3° (2°41′ to 5°43′) and holds Mercury (3°09′ Aries) and Saturn (4°11′ Aries). Mercury/Saturn is bound to fall there because the two planets are 1° apart, but the other four pairs are independent of them.
• A tight empty cluster. The last one spans only 0°31′. Its midpoints lie at 17°13′ Gemini, 17°24′ Pisces and 17°44′ Gemini, and no planet sits there. On the 90° dial, any planet reaching about 17° of Gemini, Virgo, Sagittarius or Pisces would contact all three pairs.
• A cluster with an outside planet. Jupiter/Uranus (29°23′ Scorpio), Mercury/Mars and Mars/Saturn (both at the very start of Pisces) chain together; Uranus at 1°17′ Virgo, opposite them, is at 61°17′ on the dial, within 1° of the end of the chain, so it is listed as inside.
• Switching on the Aries Point adds Mercury/Aries Point (1°34′) and Saturn/Aries Point (2°06′) to the first cluster, adds Mars/Aries Point (58°27′) to the fourth (which then also takes in Jupiter at 57°29′), and creates a new cluster around 75°36′ that the Moon (74°32′) sits in.

See also

Clusters are found by reading a midpoint sort; the pictures made by a planet inside one are listed in its midpoint tree.