Lilith is not an object
This is the first thing to settle, because a great deal of writing about Lilith assumes it is a body orbiting somewhere. It is not. Black Moon Lilith is a geometric point: the far end of the Moon's elliptical orbit around Earth, the apogee.
The Moon's path is an ellipse with Earth at one focus, so there is a near point and a far point. The far point is what astrology calls Lilith, and it is calculated rather than observed.
Two definitions, and which this uses
Because the Moon's orbit is constantly perturbed by the Sun, the apogee wanders. That produces two ways to measure it, and they can differ by as much as thirty degrees, which is more than a whole sign.
The mean apogee smooths the wobble into a steady motion. It is what nearly every astrologer means by Black Moon Lilith, it is what almost all published interpretations assume, and it is what this calculator uses.
The true or osculating apogee tracks the instantaneous position, which oscillates rapidly and can appear to move backwards. It is a legitimate measure and a minority practice, and the calculator shows it alongside the mean value so you can see how far apart they are in your own chart. The gap is often more than twenty degrees, which is why a tool that does not say which one it used is close to useless.
The headline figure here is the mean apogee, sampled from the Swiss Ephemeris, with a worst-case error under one arc second. The true apogee is derived from the Moon's own position and velocity rather than a table, which holds it to a few arc minutes rather than a few arc seconds. That is coarser than anything else on this site, and it is printed on the page rather than quietly rounded away.
Three different Liliths
The name is used for three unrelated things, which is a persistent source of confusion.
| Name | What it is |
|---|---|
| Black Moon Lilith | The Moon's apogee, a calculated point. This calculator. |
| Asteroid Lilith | Asteroid 1181, a real rock with its own orbit |
| Dark Moon Lilith | A hypothetical second moon of Earth, which does not exist |
They share a name and nothing else. Interpretations written for one do not transfer to another, and a chart showing all three will show three unrelated positions.
What it is read for
The conventional reading is appetite that refuses to be managed: the part of a person that will not be made acceptable, and what happens when it is suppressed anyway. The mythological Lilith left rather than submit, and the point carries that flavour.
In practice the placement tends to describe where someone is least willing to compromise and most likely to be judged for it. That reads as either a strength or a difficulty depending on how much room the person has been given, which is a real observation rather than a hedge.
It is a modern reading. Black Moon Lilith is not part of the classical tradition, and the interpretations attached to it are largely a product of the last few decades.
How fast it moves
The mean apogee travels through the zodiac in about nine years, so it spends roughly nine months in each sign. That puts it between the personal planets and the generational ones: shared with a cohort, but a narrow one.
The house is what makes it individual, and it needs a birth time. Lilith in the eighth house is a different proposition from Lilith in the second, whatever the sign.
Reading it honestly
Lilith attracts more dramatic writing than almost any other point in a chart, and a good deal of it is untethered. Two things are worth holding on to.
The first is that it is one point among many, and a chart is not organised around it unless it makes close aspects to the Sun, Moon or angles. The second is that the darker interpretations frequently say more about the writer's attitude to the material than about the placement.
What the position is, exactly, is settled. What it means is a convention, and one worth holding more loosely than the arithmetic.
Common questions
Is Black Moon Lilith a real object?
No. It is the far point of the Moon's elliptical orbit around Earth, a calculated position rather than a body.
What is the difference between mean and true Lilith?
The mean apogee smooths the Moon's wobble into steady motion; the true or osculating apogee tracks the instantaneous position and can differ by as much as thirty degrees. This calculator uses the mean, which is what nearly all interpretations assume.
Why do three different things share the name Lilith?
Black Moon Lilith is the lunar apogee, asteroid Lilith is asteroid 1181, and Dark Moon Lilith is a hypothetical second moon that does not exist. They are unrelated, and readings for one do not transfer.
How long does Lilith stay in a sign?
About nine months, since the mean apogee circles the zodiac in roughly nine years. That makes the sign shared with a fairly narrow cohort.
What is it read for?
Appetite that refuses to be managed, and what happens when it is suppressed anyway. In practice it tends to mark where someone is least willing to compromise.
Do I need a birth time?
Not for the sign, which the date settles. For the house, which is what makes the placement individual, yes.