Rare 'Christmas Star' Sky View Will Appear at the End of 2020 — How and When to Watch It?

The astronomical phenomenon can be enjoyed with the naked eye after sunset where there are clear skies and free visibility to the southwest of the sky.

This strange and difficult year 2020 has brought several astronomical phenomena that have been described as "rare" by the community of skywatchers. Without a doubt, the phenomenon that closes the 2020's year is one of the rarest in the time that has elapsed since it was last observed.

Next December 21, the day of the Winter Solstice in the northern hemisphere, you will be able to see the conjunction of two of the largest planets in our Solar System.

On that date, after sunset, the giant Jupiter will appear in the sky very close to Saturn, so much so that they will appear to be a single very bright star a few degrees above the horizon, southwest orientation.

Anyone with clear skies and a clear view will not need any special devices to enjoy this rare planetary phenomenon. Those with a telescope will notice that the planets appear close together side by side.

WHAT IS A CONJUNCTION

Conjunction is simply when two or more celestial bodies line up with respect to the observer's point of view. If a line is drawn from the observation point, the objects will appear aligned on that line.

Of course, they are not as close as they appear, since the distances in space are enormous. Taking as a unit the distance (astronomical unit = au) from the Earth to the Sun, Jupiter is 5 au from us and Saturn is 10 au.

WHY IS IT SO RARE

This particular conjunction is rare because the last time Jupiter and Saturn were this close was on March 4, 1224. Otherwise, these planets regularly approach each other every 20 years.

Some people, even scientists like the astronomer Johannes Kepler, thought that the "Star of Bethlehem" of the Bible story, was really a planetary alignment, conjunction, between Jupiter and Saturn and Venus. This phenomenon would be so visible and brilliant that it may have given rise to the story of the “Three Wise Men or Magi.”

TOGETHER ALL YEAR

During this year it has been possible to observe the trajectory increasingly close of the Giant Jupiter with Saturn. In the year 2000 during the last conjunction of these planets, Jupiter was close to the Sun, which made it difficult to observe it.

But this year it seems that everything has changed, recently, in November, another conjunction occurred, this time in addition to the Giant, there was also the Moon and Jupiter. Its brilliance allowed everyone who got ready to see it to enjoy a phenomenon about which little is known.

NOVEMBER 2TH IMPORTANCE

On November 2, Jupiter and Saturn experienced what astronomers call heliocentric conjunction. This is nothing more than the point where two or more planets align with the Sun.

A line can be drawn from the Sun, Saturn, and Jupiter, they are all on the same line. As they get closer each night, they can see each other as one for December 21, at the solstice.