Two methods for a group midpoint
The simple arithmetic average of degrees depends on where the zodiac’s 0° point is placed. Three Suns at 350°, 10°, and 60° average to 140° if their printed numbers are added, even though the positions cluster near 20°. This calculator instead works on a circle.
Circular balance point finds the longitude with the least total squared shortest-arc distance from the three or four natal positions. It checks every possible interval and reports all equally good answers. Vector centre of gravity averages unit arrows pointing at those longitudes. The arrow’s direction is the result; when arrows cancel, no direction exists. These two group methods can produce different longitudes, so the result always names the selected rule.
Angles, houses, and birth-time limits
When every birth time is recorded, the same selected rule aggregates the natal Midheavens. The tool then solves a sidereal orientation with that MC at your reference latitude and asks the local house engine for an Ascendant and cusps. That solved clock is a geometric device. The group planets are calculated from individual natal charts, not from its sky. A different reference latitude or house system can change the houses without changing the group planetary positions.
If even one time is unknown, that record’s planets use 12:00 on its local birth date. The Moon and any position near a sign boundary are especially uncertain. Group MC and houses are withheld. Tied balance points or a cancelled vector are omitted from the wheel and cannot receive a house. The two-person composite and a Davison chart are different calculations.
Astrological interpretations of a group are subjective; the chart cannot measure a group’s safety, consent, or likely outcome.