Those with clear skies were in for a special treat these days, when the planets Jupiter and Saturn began their dance around each other, which would bring them to a very close tête-à-tête on December 21, 2020. The astronomical community calls these rare close encounters “great conjunctions“. They occur approximately every 20 years when Jupiter “overtakes” Saturn in its orbit. This year’s great conjunction was the closest since 1623 and the closest observable since 1226, and won’t be matched again until the extra close Jupiter-Saturn conjunction in March 2080. During their closest alignment the gas planets were just a tenth of a degree apart, i.e., you could cover them both with your pinkie finger at arm’s length. Although they appeared so close together on the night of the conjunction, they were actually some 734 million km apart.
Jupiter and Saturn with the waxing moon on December 17, 2020.