A very rare celestial phenomenon will take place on 21 December night when the two biggest planets of the solar system, Jupiter and Saturn, comes closure to each other probably appearing them as a big elongated single planet, Professor Chandana Jayaratne, the Director of Astronomy and Space Science Unit, University of Colombo.
‘You can look at the western skies these days after the Sunset and you will see the two planets are gradually coming closer to each other and the closet approach will occur on 21st December 2020 when the two planets will be separated by just about one-tenth of a degree or 6.1 arc minutes.
On December 21st the two planets will set down at 8.14 p.m. Therefore, to watch this spectacular event, it is better to select a place where you can see the western skies clearly without much trees or buildings. About 30 minutes after the sunset, say from 6.30 p.m. – 7.30 p.m. period, look at the western skies closer to the horizon and towards somewhat northwest direction, you would see the two planets, perhaps as a double star or an elongated ball of light. Naked eye observation is possible or you may use a binocular.
In their elliptical movement around the Sun, Jupiter passes Saturn in a conjunction every 19.6 years, so the event is already rare, but on this December 21, the event will be the closest in recent history. The last time these two planets appeared so close was 397 years ago, on July 16, 1623, when they were only 5 arc minutes apart. That was 13 years after Galileo built his first astronomical telescope and discovered the four large moons of Jupiter, the rings of Saturn and Sunspots among other discoveries.
Astonishingly, we will get another conjunction of the two planets with 6-arc minute separation in 60 years time, on March 15, 2080’ said Professor Jayaratne.