Transits and Retrogrades Explained

A transit is where a body actually is right now, and the angle that live position makes to a fixed degree in the chart cast for your birth. The second half is the one people skip. The sky is public — Saturn sits at the same degree for everyone alive at this moment — but the contact is private, because it depends on where your own Sun, Moon and planets stood on the day you were born. This page is about timing: how a transit is measured, why transit speed rather than planetary importance decides which contacts anyone ever notices, the return cycles with the arithmetic behind their famous ages, and what a retrograde does to the length and shape of a contact. Why nothing actually reverses is a separate question with a separate page.

The sky is shared. The contact is not.

A birth chart is a snapshot and it is frozen. Every degree in it stays exactly where it was at the moment it was cast, forever. A transit is the moving sky meeting that frozen snapshot: take the current ecliptic longitude of a body, take the fixed natal longitude of one of your own placements, and subtract. If the answer exceeds 180°, subtract it from 360°. What is left is the transit's angle, measured in exactly the same way a natal aspect is.

Worked example, with three people and one Saturn. Say Saturn is transiting at 12° Aries, which is 12° of longitude because Aries begins at 0°. Person A has a natal Sun at 14° Cancer — 90 + 14 = 104°. The difference is 92°: a square, 2° from exact. Person B has a natal Sun at 14° Libra, which is 194°. The difference is 182°, which exceeds 180°, so the separation is 178°: an opposition, also 2° from exact. Person C has a natal Sun at 12° Sagittarius, which is 252°, giving a difference of 240° and therefore a separation of exactly 120° — an exact trine.

One Saturn, one degree, three completely different contacts on the same afternoon. "Saturn is in Aries" is a fact about the sky. "Saturn is squaring my Sun" is a fact about the sky and about one birth moment — which is precisely what a column addressed to twelve Sun signs cannot deliver, because it knows the sky and does not know your degrees.

Three things a transit is not

• Not a force. Astrology describes a correspondence between a sky position and a theme. Nothing on this page claims a mechanism, and no mechanism is known.
• Not the same as a sign ingress. "Mars enters Gemini" is the sky moving through the zodiac. A transit to your chart additionally needs one of your own natal degrees to land on.
• Not a schedule of events. A transit produces an angle and a date range. It does not produce an outcome. See what we do not claim.

Speed decides which transits anyone notices

The difference between a transit people write books about and a transit nobody has ever mentioned is not importance. It is duration.

Count a contact as live from 1° before exact to 1° after — a 2° window, a tight but common working convention for transits. Then the length of the contact is simply 2 divided by the body's daily motion, because the natal degree does not move. The Moon covers 11.8° to 15.3° a day, so a 2° window is gone in three to four hours. Saturn covers about 12.2° a year, roughly 0.033° a day, so the same window holds for about two months. That is a factor of just over 400, and it is the entire explanation for why one of them reads as a season of a life and the other does not register at all.

How long each body takes to cross a whole sign is a different question, measured rather than derived, and the planets in astrology has that table. Two consequences fall out of this one. First, only the slow transits stay in orb long enough for a person to notice a pattern, name it and later write about it — so the literature is weighted toward Saturn and the outer planets for reasons of observability, not cosmic significance. Second, a slow transit is often not a single contact: because a slow planet stations retrograde and then direct, it can cross the same natal degree three times, once forward, once backward, once forward again.

That second point is the one everyone overstates, so it is worth pinning down rather than repeating. The triple pass happens only when your natal degree falls inside that year's retrograde arc. The next section works out how often that is.

The life-cycle transits, and the arithmetic behind them

A return is the moment a body comes back to the exact longitude it held at your birth. Nothing about its timing is mysterious: it is the orbital period. Saturn takes 29.46 years to go round, so it returns at about 29 or 30 and again at about 59. Jupiter takes 11.86 years, so it returns roughly every twelve. The famous ages are division problems, and you can do them yourself.

One correction before you do. Those are sidereal periods, measured against the fixed stars, and astrology reads the tropical zodiac, measured from the March equinox point — which itself drifts westward by about 1° every 72 years. A body therefore comes home to a tropical degree slightly sooner than it comes home to a star. For Saturn the tropical return period is about 29.42 years rather than 29.46, roughly twelve days earlier per lap. Over one return that is nothing; over three laps it is about five weeks. The ages below use sidereal periods and are unaffected at the precision they are quoted to.

How to work out any cycle transit yourself

1. Take the body's orbital period in years: Jupiter 11.86, Saturn 29.46, Uranus 84.0, Neptune 164.8, Pluto 247.9, the lunar nodal cycle 18.6.
2. Multiply by whole numbers for the returns: one period, two periods, three.
3. Halve it for the opposition, when the body sits 180° from where it started.
4. Quarter it for the first square, and take three quarters for the second — 90° after the start, and 90° before the return.
5. Read the ages straight off. Uranus at 84 years gives squares near 21 and 63 and an opposition near 42.
6. Then check an actual ephemeris, because that arithmetic assumes even motion round a circle and no real orbit obliges. Eccentricity and retrograde loops move the true date by months.

What a retrograde does to a contact

Retrograde motion is a viewing angle, not a reversal — no planet has ever slowed, stopped or turned around, and what does retrograde mean has the geometry, the stations, the measured frequencies and the reason the folklore does not survive its own numbers. What belongs here is narrower: what a retrograde does to the timing of a transit.

Two things, and the first is small. Normally the faster body applies to an aspect, closing the gap, and then separates. A retrograde swaps which is which, so a contact that was separating starts closing again.

The second is the one that matters. Between its two stations a planet covers the same stretch of zodiac three times — forward, back, forward — so any natal degree inside that stretch gets three exact contacts instead of one. Whether yours is inside it is a geometry question with a checkable answer: compare how far back each loop reaches against how far the loops move along the zodiac between one retrograde and the next.

The last two rows are the payoff, and they are not a rounding artefact. Neptune's loop backs up 2.8° while a year only carries the loop forward 2.2°, so consecutive loops overlap: there is no degree of the zodiac Neptune passes cleanly, and a band of them get five exact contacts spread across two years. Pluto is more extreme still. For the outermost planets the three-pass contact is not the exception, it is the only kind of contact there is — which is a large part of why an outer-planet transit reads as a period rather than an event.

Read the column as an ordering, not a probability. It is a geometric expectation from mean rates, and mean rates are not what real orbits do. The one case Zodiux has measured directly rather than derived — three exact contacts at a first Saturn return, scanned across 4,749 birth dates — came out at 37.8%, well below the roughly half the geometry predicts. Where a measurement exists, trust it over this table.

Reading a transit yourself, in order

Zodiux does not have a button that prints your transits, and this page is not going to pretend otherwise. It gives you both halves and leaves the subtraction to you. The free birth chart prints every one of the ten bodies by sign and by whole degree inside that sign, marks any that was retrograde at your birth minute with ℞, and adds the Ascendant when you give a birth time. The live sky prints the same three things for the sky right now. Everything between those two numbers is arithmetic.

The method, step by step

1. Convert your natal placement to longitude: sign index × 30, plus the degree within the sign. Aries starts at 0°, Taurus 30°, Gemini 60°, and so on to Pisces at 330°.
2. Read the transiting body's current longitude the same way, from the live sky.
3. Subtract one from the other. If the result is more than 180°, subtract it from 360°.
4. Compare what is left against 0°, 60°, 90°, 120° and 180°. Inside the orb you have chosen you have a contact. A 1° allowance is a sensible working figure for transits — much wider and everything aspects everything.
5. Look up the transiting body in the speed table above. That tells you how long the contact holds, and the triple-pass table tells you whether to expect one crossing or three.
6. Check whether the body is currently retrograde. The live sky marks it, and it decides whether the contact is closing or opening.
7. Read the slowest contact first, and mostly only that one. The fast contacts are real and they are also over in hours.

Two cautions about the numbers you are working with. Degrees on this site are floored, not rounded: a Sun at 21.98° of Cancer displays as 21°, so your own precision is a whole degree and a 1° transit orb is already at the edge of what the display can resolve. And the 1° figure above is a transit convention, not the site's natal convention — the chart's own aspect engine uses flat orbs of 7° for a conjunction, 5° for a sextile, 6° for a square and 7° for trines and oppositions, which what are aspects in astrology sets out along with why any orb is a settings choice rather than a finding.

Then stop. The method produces an angle, a direction and a date range — three concrete, checkable things. It does not produce an outcome, and the gap between those two is where most astrology writing quietly goes wrong.