Transits
Aspects and transits calendar
A month of the sky: every exact aspect, sign change, retrograde turn and moon phase, with the wheel for any day you pick.
Pick a month and the calendar solves for the moment each event is exact, rather than reporting where the sky happens to be at noon. Choose a day to open the wheel drawn for it. Everything is calculated in your browser.
Reading a transit calendar
A transit is simply where the sky is now, set against something fixed. On its own, the month below is the sky against itself: Mars meeting Saturn, Venus changing sign, the Moon turning full. Add a birth date and a second reading opens, because the same moving bodies are then measured against the positions they held when you were born.
An exact time is a statement about geometry, not about a day. Nothing here predicts an event, and a precise minute for an aspect says nothing about what any minute will hold. Astrologers read transits as periods rather than instants, and the wheel for a day is a better place to start than the timestamp beside it.
What the calendar lists
- Aspect
- Two bodies in the sky reach one of the five major angles exactly.
- Transit
- A body in the sky reaches an exact angle to a point in your birth chart.
- Sign change
- A body crosses from one sign into the next.
- Retrograde
- A planet appears to stop and turn, ending one direction of travel and beginning the other.
- Moon phase
- The Moon reaches a quarter of its cycle away from the Sun.
- Void of course
- The Moon has finished its last major aspect and has not yet changed sign.
How these times are found
Every event on this page is a moment when something in the sky becomes exactly true, so the calendar solves for a time rather than reading a position. It samples the whole month at six-hour steps, watches for the quantity that defines each event to change sign, and then narrows the interval by halving until the answer settles to the second. Where a planet turns so close to a degree that it reaches it and backs off between two samples, the calendar finds the turn itself and lists both crossings.
- An aspect is exact when the angle between two bodies equals 0°, 60°, 90°, 120° or 180°. Both sides of an angle count separately: a planet can be 60° ahead or 60° behind, and those are two different sextiles.
- A sign change is a crossing of a multiple of 30°. A retrograde body can cross the same cusp backwards, and that return is listed too.
- A retrograde turn is where apparent motion passes through zero, measured across a whole day centred on the moment — the same window the chart uses to decide whether a planet is retrograde at all.
- A moon phase is where the Moon’s distance from the Sun passes 0°, 90°, 180° or 270°. New and Full are the first and third of those.
- Alongside the Sun, Moon and planets, the calendar follows three points. The North Node and Lilith are the mean lunar node and the mean lunar apogee, Lilith projected onto the ecliptic; the mean node always moves backwards and mean Lilith always forwards, so neither ever turns. Both agree with Swiss Ephemeris to within a twentieth of an arcminute across 1800–2050. Chiron is placed from JPL Horizons’ orbital elements and agrees with Horizons to within an arcminute over the same span. Transits reach the three points in your own chart too. On the wheel and in its aspect list, an aspect with a point at either end is held to half the planets’ orbs — a convention that weighs the points below the bodies, not a measured quantity. The exact times in the calendar do not depend on orbs.
- The void-of-course Moon is not calculated separately: it is the gap between the Moon’s last exact aspect and the moment it changes sign. This site reads it against the Sun, Moon and eight planets, which is the modern convention, and not against the calculated points; older practice counts only the visible planets and produces slightly longer intervals.
How exact these times really are
The narrowing is exact to the second, but a time is only as good as the ephemeris beneath it, and this site calculates positions rather than reading a published table. Each event therefore carries its own margin: the measured positional error of the bodies involved, divided by how fast they are actually separating, doubled for safety.
That works out very differently across the chart. A Moon aspect is good to about a minute. The Sun entering a sign — the equinoxes and solstices — is good to about a quarter of an hour. A Saturn or Neptune sign change moves so slowly that a small positional error becomes days, and the calendar says so rather than printing a time that looks authoritative. Retrograde turns show a date without a time, because motion at a station is zero by definition and there is nothing to divide by.
The four 2026 equinoxes and solstices are locked in the test suite against their published times, and each one lands inside the margin this page prints for it.
What happens to what you type
Every calculation on this site runs in your browser. There is no account and no server that receives a name or a birth date. Shared links carry reading details after the # in the address, which browsers do not transmit to a server. Calcabala counts visits with Google Analytics only if you accept it — and it is given the page address with everything after the # removed, so a shared reading never reaches Google either. Decline or change your mind from “Cookies” at the foot of any page.
City coordinates and time zones from GeoNames, used under CC BY 4.0. The list is bundled with the page: choosing a birth city never contacts a server.
Common questions
Why does the calendar hide Moon aspects by default?
The Moon makes about three or four exact major aspects a day, which is around a hundred a month — more than every other body together. They are one checkbox away, and a day you open always lists all of its own regardless.
Why do some events show a margin of days?
Because the position they depend on is only known to a few arcminutes, and a slow body takes days to cross a few arcminutes. Jupiter and Saturn are the least precise bodies in this ephemeris, so their sign changes and their aspects to other slow planets carry the widest margins. Fast events are unaffected.
Which time zone are these times in?
The one shown above the calendar, which starts as whatever your browser reports. Days begin and end in that zone too, so an event just before midnight moves to the neighbouring square if you change it.
What is a void-of-course Moon?
The stretch after the Moon has made its last major aspect in a sign and before it enters the next one. Traditionally it is read as a period when matters begun do not come to much; here it is simply reported as an interval, with the aspect that ended and the sign that follows.
Do I have to give my birth details?
No. The calendar is complete without them. A birth date adds a second track of events — the sky reaching exact angles to your own chart — and a birth time and city sharpen the Moon and allow houses. None of it is transmitted; the page has no server to send it to.
Calcabala calculates astronomy and reports symbolism. Nothing on this page is a prediction, and no event listed here causes anything.