The stretch where the Moon declines to answer.

The Moon moves quickly through the zodiac: about two and a half days in a sign, then on to the next. As it goes it makes aspects to the Sun and planets — conjunction, sextile, square, trine, opposition. An aspect 'perfects' when the angular distance between the Moon and the other body reaches that aspect's exact degree.

If the Moon will perfect no further major aspect before leaving the sign it is in, the stretch between that last aspect and the sign change is called a void-of-course Moon. So a void is not an event but an interval: it begins when the last aspect completes and ends when the Moon enters the next sign.

Its length is not fixed at all. If the Moon makes its final aspect just before exiting, the void lasts minutes; if it made it early, the void can run most of a day. Which is why 'is the Moon void today' is a question about an hour rather than a day — and why most of the tables online skip precisely that distinction.

There are two ways to decide when an aspect has perfected. The common one is to pick a tolerance: call it perfected once it comes within, say, 0.5 degrees of exact. Easy, and fragile — because then the number you chose decides the answer rather than the sky.

An earlier version of the app did exactly that: sample every 30 minutes, ask whether an aspect sat inside a 0.5 degree orb at that instant. It erred in both directions at once, missing aspects that perfected between two samples and counting ones that had already separated. Measured against a two-minute scan it gave a different answer on 0.8% of hours, and widening the orb to 1 degree moved the answer on 2.4% of them.

That second number is the decisive one. A measurement whose result moves when you adjust its tolerance is measuring the tolerance, not the sky. So the method changed: track the signed separation between samples and find the point where it crosses the aspect angle. A crossing is a crossing however coarsely you sample, so the answer no longer depends on an orb at all.

Horary casts a chart for the moment a question is asked. In the classical tradition a void Moon is the sign that this particular moment cannot be read: nothing is coming to pass, the matter is not moving, the chart declines to answer. The tradition is unambiguous about it.

Baby Astro enforces that. Ask a horary question while the Moon is void and the app produces no answer, and takes no credit for the refusal. A rule that is not enforced is decoration rather than a rule, and charging for a reading you then decline to give is, at best, dishonest.

There is a second consequence: we can tell you when the void ends. Because the app computes the moment the Moon changes sign, it also knows the moment the question becomes askable again. In notifications that appears as the Moon leaving void, and it is computed entirely on your device.

Tradition reads a void as an interval unsuited to starting something new. Signing, pitching, launching — forward moves are discouraged; resting, reviewing, finishing what is half-done and closing off delayed business are considered well suited to it. Briefly: good for closing, not for opening.

Now what it is not. A void Moon does not mean something bad will happen, and there is no evidence that bad things cluster inside one. The app presents it as a timing marker rather than a warning, makes no guarantees about the future, and gives no medical or financial advice.

If you genuinely want a moment to begin something, the void calendar is not the tool. Electional timing computes the cleanest window of your day from your own chart, and tells you separately when the Moon is void.