The Great Conjunction of Jupiter and Saturn – Dec. 21st 2020

This coming Monday the 21st of December 2020 is the Great Conjunction of Jupiter & Saturn.

Given that this is so close to Christmas it is often mistakenly called the Christmas Star.

This event occurs in a regular pattern once every 20 years however what makes this event special is the rare opportunity to see the planets appearing close enough to almost be a single ‘star’. This is brilliant for astronomers as they can observe this event within the same field of view of their telescope. According to what I have read, the planets last appeared this close in 1623.

It is also an event of significance because it’s been close to 800 years since the alignment of Saturn and Jupiter occurred at night, making for easy observation.

They won’t appear this close again until 2080.

I’d also add that December 21st is also when the Sun’s track across the Australian sky reaches its highest point. It is the day that we have the most daylight hours of any other day in the year. The summer solstice more frequently occurs on 22 December, but can occur between the 21st and 23rd of December.

As always, these things have an equal and opposite effect and so in the Northern Hemisphere it will also be the mark of the Winter Solstice. I have always had a sense, particularly in our Southern Hemisphere Winter Solstice, that the days actually got shorter and darker after the solstice. I have not been mistaken and I have found the explanation at last!

The winter solstice is the shortest day in the Northern Hemisphere but not the day with the latest sunrise and earliest sunset. How is that possible?

The winter solstice doesn’t coincide with the latest sunrise or the earliest sunset. Those actually occur about two weeks before and two weeks after the winter solstice. This is because we are changing our distance from the sun due to our elliptical, not circular, orbit, which changes the speed at which we orbit.

This comes from this webpage from The Conversation.

A few more things to know if you wish to view this event.

The Dyer Observatory which is owned and operated by Vanderbilt University and is located in Brentwood, Tennessee, will have a live streaming of the conjunction of Jupiter and Saturn.

You can view the Great Conjunction of Jupiter and Saturn Live here.

For those is the US it will be live between 5 – 6pm CST on the 21st of December 2020.

For those viewing in the UK it should be live by 11 pm on the 21st of December.

For us Aussies it will be live on Tuesday the 22nd of December from 10 -11am EST.

Of course, for us West Aussies we’ll get it a little earlier and can watch it eating breakfast at 7am on the 22nd. . . . and if you haven’t worked it out – 9:30 am for SA.

This ABC site has a great slide view of what to be looking for in the evening sky.

And for those that can remember I just had to include this for some reminiscing.

Further Information:

Ideas for the Summer Solstice

Vanderbilt Dyer Observatory

USA Today article

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