Knowledge
Vertex
The Vertex is the point where the ecliptic intersects the prime vertical on the western side of the sky. The prime vertical is a circle passing through the east, west and zenith points. The Vertex is read as a point of meetings and events that come through other people, so it is considered in relationship contexts.
Where the Vertex comes from
The point was introduced in the 1920s by American astrologer Lorn Edward Jondro, who called it the “electric Ascendant”; it was further developed by Charles Jane. It is a later point: it is absent in classical astrology, and in modern practice it is used only by a subset of astrologers.
How it is calculated
The Vertex is calculated from the same data as the Ascendant: sidereal time, latitude and the obliquity of the ecliptic. It can be understood as an Ascendant built as if the IC of the chart became its MC. The point almost always lies in the western half of the chart, in the fifth to eighth houses, and directly opposite it is the Anti-Vertex.
How it is interpreted
The sign and house of the Vertex describe meetings and circumstances that feel as if they have come from outside, rather than chosen. Transits and synastry contacts to the Vertex, especially conjunctions with another person's personal planets, are linked to memorable encounters. A narrow orb is used — one to two degrees.
Anti-Vertex
The Anti-Vertex lies on the eastern side of the chart, 180° from the Vertex. It is read as the side of the same axis that depends on you: if the Vertex represents what comes to you, the Anti-Vertex represents how you respond.
Why cautiously
The Vertex has no classical tradition or established rules, and its meaning is mainly described through practitioners' observations. We present it as an additional point rather than the primary indicator of a partner: the Descendant sign, the ruler of the seventh house and Venus carry more weight.
Why birth time is needed
The Vertex moves through the zodiac as quickly as the Ascendant — about one degree every four minutes. Without an exact birth time its position is unknown. Near the equator the prime vertical is close to the meridian, and the Vertex shifts toward the edge of the western half of the chart.
Vertex on the platform
In Mira’s natal chart the Vertex is not yet present: the decision whether to include it in the portrait of a future partner has not been made. This page is an information note about a point you will encounter in other software.