Great Conjunction between Jupiter and Saturn
These occur roughly every 20 years, with the next one in 2080. According to Sky and Telescope, “During this period, Saturn completes two-thirds of its 30-year orbit, while Jupiter completes one lap of its 12-year orbit plus two-thirds of its next one. The odd two-thirds of an orbit mean that successive conjunctions are separated in the sky by about 240 degrees.”
Back in 1606, Johannes Kepler recognized these conjunctions and created a near-perfect triangle on the zodiac circle. The last conjunction was in 2020, and after the next one in 2080, the next ones will occur in 2417 and 2477 (Sky and Telescope).