What is my Big Three?

The Big Three are the Sun, the Moon and the Ascendant — usually called the rising sign. They get grouped together because between them they cover three different questions, and most of what people find confusing about astrology comes from expecting one sign to answer all three.

The Sun is what you are trying to become, and what you get recognised for when it goes well. It is the sign you already know, because it only needs your birthday.

The Moon is what settles you — how you react before you have decided how to react. It moves about thirteen degrees a day, so it usually needs your birth date and can shift signs partway through it.

The Ascendant is the sign that was coming up over the horizon at your birth. It is the first impression, and the doorway the rest of the chart is arranged around. It changes roughly every two hours.

Because of the third one. The Sun takes a year to cross the zodiac and the Moon takes a month, but the Ascendant runs through all twelve signs in a day. Without a time there is no Ascendant to give you — not an uncertain one, none at all.

The Moon is the in-between case. Calculated from midday, its sign is wrong in roughly one chart in nine — about 11%, measured across 9,600 test charts. So a Big Three without a birth time is really a Big Two and a maybe.