Solar Return Calculator

Overview

A solar return is the instant the Sun regains its natal ecliptic longitude. Finding it is a root-finding problem on an ephemeris — precisely solvable — but the chart drawn for that instant depends on a location choice the tradition does not settle.

• The return moment is found by solving for when solar longitude equals the natal value.
• It drifts about six hours later each year and resets at leap days.
• The chart's houses depend on which location is used, and practitioners disagree.
• The same arithmetic gives lunar returns and returns for any other body.

Finding the return instant

The natal Sun's ecliptic longitude is a fixed number. Finding the solar return means solving for the time at which the Sun's longitude equals that value again — a root-finding problem, normally handled by iterating on an ephemeris until the difference falls below a tolerance.

The Sun moves about one degree per day, so the longitude changes fast enough that the solution converges quickly and is well conditioned. The answer is exact to within the ephemeris precision, which is far finer than any interpretive use requires.

Why it drifts against the calendar

The tropical year is about 365.2422 days. The civil calendar uses whole days with leap-day corrections, so the return instant falls roughly six hours later each year and jumps back by nearly a day when a leap day intervenes.

Over a four-year cycle the return therefore migrates across roughly a day of calendar time, which is why it can fall on the day before or after a birthday and at a very different clock time each year.

The location problem

Once the instant is known, the chart requires a location to compute the Ascendant and houses. Practitioners disagree about whether to use the birthplace, the current residence, or the person's actual location at the return moment.

The choice materially changes the chart, since the Ascendant advances roughly a degree every four minutes and the whole house structure follows it. This has produced the practice of relocating for a solar return, and whether that is meaningful is disputed within the tradition. It is a clear example of an interpretive framework generating a question that no computation can settle.

Returns for other bodies

The same root-finding applies to any body. A lunar return recurs about every 27.3 days, so the arithmetic is identical but the solution is found more often and the convergence is faster because the Moon moves about 13 degrees per day.

Planetary returns follow the body's orbital period: a Jupiter return roughly every twelve years, a Saturn return roughly every 29.5. Those intervals are genuine orbital facts, independent of any interpretation placed on them.

Continue in the data

Catalogues, hubs, and reference pages that hold the underlying records for this topic.

• Solar returnWhat the tradition makes of the chart.
• Celestial eventsTropical years, equinoxes, and orbital returns.
• Scientific calculatorsExecutable orbital-period calculators.

Frequently asked

How is the solar return moment calculated?

By solving for the instant when the Sun's ecliptic longitude equals its natal value — a root-finding problem, normally handled by iterating on an ephemeris until the difference is below tolerance. Because the Sun moves about a degree per day, the solution converges quickly and is precise to well within any interpretive requirement.

Why does my solar return fall on a different date each year?

Because the tropical year is about 365.2422 days rather than a whole number. The calendar absorbs the fraction with leap days, so the return instant drifts roughly six hours later each year and jumps back when a leap day occurs — migrating across about a day of calendar time over the four-year cycle.

Which location should a solar return chart use?

There is no agreed answer. Practitioners variously use the birthplace, the current residence, or wherever the person actually is at the return moment, and the choice changes the Ascendant and every house cusp. It is a convention within an interpretive framework, and no computation can resolve it.