Saturn return calculator

Saturn takes about 29 and a half years to travel once round the zodiac. Your Saturn return is the time it spends coming back to the degree it occupied when you were born. The first arrives in your late twenties, the second in your late fifties, and a third, for those who reach it, in the late eighties.

Astrologers read Saturn as the planet of structure, limits and time, so its return is treated as a checkpoint: a season for taking stock of the commitments, work and habits you have built, and choosing which of them you mean to keep. Astrology reads it as a question the period asks you rather than an event that happens to you.

Seen from Earth, Saturn appears to move backwards for about four and a half months of every year. If one of those retrograde spells falls across your natal degree, Saturn crosses it three times, forward, back and forward again, over seven and a half to nine months. If not, it crosses once. For births from 1930 to 2010, about six first returns in ten are a single pass and four in ten are three; for the second return it is the other way round.

So the calculator gives you three kinds of date. The exact passes, with the retrograde one marked. The stretches when Saturn is within one degree of your natal Saturn, the orb most astrologers use for a return in progress: anything from two weeks to about four months in all, sometimes in two or three pieces. And the longer period Saturn spends in your Saturn sign, between two and nearly four years, which many astrologers count as the return's wider season.

StarMap first works out where Saturn was at the moment you were born, in the tropical zodiac, with astronomy-engine, an open-source ephemeris that agrees with the Swiss Ephemeris to within about an arcminute. It then follows Saturn forward through the years a return can fall in, notes each time it crosses your natal degree, and narrows each crossing to the minute. For births from 1930 to 2010 the first exact pass falls between the ages of 28.4 and 29.9, and the second between 58.2 and 59.0.

The dates on your result are shown in the time zone your browser is set to, and the result says whether each return is behind you, under way or still to come.

You can still use the calculator. Saturn moves slowly, never more than about eight arcminutes in a day, so the birth date alone fixes its position closely. Without a time, the dates are worked out for noon on your birth date, and the result says how far they could move: usually by one day, and by up to a week when Saturn is turning round close to your natal degree. For about one return in a hundred, Saturn turns so close to that degree that the number of passes depends on the hour, and the result says so when it applies to you.

Put the dates in a calendar and read the description of your Saturn sign under the result: the sign describes the kind of structure the return tests. Your whole chart adds the house Saturn falls in, if you know your time, which says which part of life the return is read as being about, and the aspects Saturn makes to your other planets. If the return is under way now, the sky today shows where Saturn is this month, and the guide to reading a birth chart explains houses and aspects in plain words.