Jupiter and Saturn: the Great Conjunction
When the two slowest bright planets meet, astronomers call it a great conjunction. It is the rarest of the bright-planet pairings, returning only about once every twenty years, which is why each one is a landmark of the sky.
Computing the next conjunction…
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Dates and positions are computed live in your browser and are accurate to well under a degree. "How close" is the separation along the ecliptic; the zodiac position is the tropical longitude (0° at the spring equinox).
About this pairing
Jupiter and Saturn line up in our sky about every 19.86 years, the slow beat set by their long orbits. Each conjunction lands roughly 117 degrees further around the zodiac than the last, so three of them, close to sixty years, nearly return to the same region and trace a slowly turning triangle that Kepler drew and called the trigon.
The conjunction of December 21, 2020 was the closest since 1623, the two giants separated by only about a tenth of a degree, roughly a fifth the width of the full Moon; widely shared as a "Christmas Star," it was a genuinely rare close pass. Kepler himself studied the great conjunction of 1603 and connected the cycle to the Star of Bethlehem question.
Over roughly eight centuries the meeting works through all four groups of zodiac signs, a long pattern known historically as the great mutation. You can place these conjunctions in that wider rhythm on the Cycles by Length page, and find the exact dates for any pair of planets with the Planetary Alignment Calculator.
Frequently asked questions
When is the next great conjunction of Jupiter and Saturn?
Jupiter and Saturn line up about every 19.86 years. The most recent great conjunction was in December 2020, and the next is in 2040.
What is a great conjunction, and why was 2020 special?
A great conjunction is a meeting of Jupiter and Saturn, the two slowest bright planets, the rarest of the bright-planet pairings. In December 2020 the two passed only about a tenth of a degree apart, their closest since 1623 and roughly a fifth the width of the full Moon.
Other conjunctions
Keep exploring
Planetary Alignment Calculator
Conjunction and opposition dates for any pair of planets, and multi-planet line-ups.
SkyToday in the Sky
Where the Sun, Moon and planets sit right now, and the next sky events.
InteractiveThe Live Orrery
Watch the planets move and see these meetings unfold from above.