The Jupiter-Saturn conjunction cycle has an interesting rhythm. I ran a computer search over a span of 4,500 years from years -1500 to +3000, or 276 close approaches to see what came up. In the graph below each point shows the closest separations between the two planets over the 276 conjunctions. They vary from about 1.5 arc minutes to 80 arc minutes. Most close approaches while eye catching are not remarkable. Out of the 276 conjunctions only seventeen came to within the range of this December's separation.
Jupiter and Saturn catch up with each other every 20 years and every 60 years are especially close. Last one was 1961 when they approached to 14.7 arc minutes apart. This time around on 21 December they will be closer at 6.1 arc minutes. Sixty years on in 2080 they are a tad closer at 6.0 arc minutes apart.
The closest approach of all during the entire span occurred on -423 December 28 when the two planets were only 1.5 arc minutes apart. Only the keen sighted might have been able to split them. It is not until 2874 December 25 do they once more make and eye-challenging conjunction at 2.3 arc minutes apart.
Edited by Marty0750, 29 November 2020 - 09:38 AM.