What is Chart Rectification?

The time of birth is not always known — it may not appear on any document, the family may not remember, or all that survives is a rough guess like "towards morning". Rectification is the technique of estimating the birth time backwards, using significant events that have already happened.

Why the time matters so much

The birth time determines the Rising sign and the house system (see natal chart). The Ascendant shifts roughly one degree every four minutes — so even twenty or thirty minutes of uncertainty can move the Ascendant by several degrees, sometimes into the next sign entirely. House cusps are just as sensitive to the time.

The method: working back from events

In rectification, significant events in a person's life whose dates are known precisely — marriage, a change of job, a move, a major loss — are listed. Then different times within the plausible range are tried, looking for the one that matches those dates most consistently under transits and progressions.

An example: if someone married at 28, and at one end of the possible time range the 7th house (relationships) receives a strong transit or progression while at the other end it does not, the true time is taken to be more likely near the first end.

Probability, not certainty Rectification does not produce a mathematical proof — it narrows down the range that looks most consistent with a person's history. The more events used, and the more varied they are, the more reliable the estimate is considered; but the result is always a most likely range, never an exact second.

When it is needed

When the birth record shows no time at all
When family members remember different times
When there is persistent inconsistency between the known time and lived events

Once the time is settled, techniques that are extremely sensitive to it — such as progressions — can finally be used reliably.

Natal Chart

The time-dependent chart rectification sets right.

Horary (Question Chart)

A different technique that needs no birth time at all.

ALVEM's Rectification screen compares the significant events you enter against transit and progression matches across different time ranges.