Why your birth time matters

Your birth date fixes where the Sun, Moon and planets stand. Your birth time and place fix something else: how the sky is turned relative to the spot where you were born. That turning decides your houses and the four angles of the chart (Ascendant, Midheaven, Descendant and IC), which is why time of birth is worth finding.

What the time changes

The Ascendant, the sign rising on the eastern horizon, advances roughly one degree every four minutes, and the whole zodiac passes over the horizon in about 24 hours. A sign rises for about two hours on average. That means a difference of a few minutes can shift the Ascendant by several degrees, and a gap of an hour or two can change the Ascendant sign entirely.

The Midheaven, the highest point of the chart, and all the house boundaries move with it. If your time is off, planets can appear in the wrong house and the chart can describe a slightly different life emphasis.

Planets and the Moon

The planets themselves barely move over a few hours, so the Sun and most planets stay in the same sign. The Moon is the exception. It travels roughly half a degree per hour, so across a day it covers about 13 degrees and can change signs.

Where to find your time

• Your birth certificate or hospital record, which often has the exact minute.
• A parent or relative who remembers it.
• A baby book or hospital bracelet.

Times rounded to the hour or half hour are common. Treat them as approximate.

If you do not know your time

Natalora supports an unknown birth time. In that case the chart is calculated for 12:00 noon on your birth date, houses and angles are left out because they cannot be trusted, and the Moon is shown as approximate, since it may have been up to about six or seven degrees either side of the noon position.

An unknown-time chart is still meaningful. Sun sign, planet signs and most aspects remain valid. You simply lose the Ascendant, the Midheaven and the house placements.