Jupiter & Saturn positioning

[Joe G]

Hi apologies if this query has already been answered but I can’t find it. I have been viewing Jupiter & Saturn lately & I’ve been wondering why they have started to appear in the night sky later each year. It then struck me that, if I recall right, Jupiter used  to always appear before Saturn . Has Saturn overtaken Jupiter or are I just having a bit of a “Senior Moment “. If I’m correct,is it to do with their distances from earth/ speeds of their orbits etc? 
I would appreciate any feedback from more more knowledgeable people on this forum & thanks in advance 

[vlaiv]

57 minutes ago, Joe G said:

If I’m correct,is it to do with their distances from earth/ speeds of their orbits etc? 

Yes.

They appear later in the year each year because they move small amount on their respective orbits as we do one full revolution around the sun.

In fact - each successive night they appear earlier - but also move in the sky a bit. One is due to our orbit around the sun and other is due to their orbits.

You can download and install free software called Stellarium - that is planetarium software that displays position of stars and constellations with respect to selected time and your location. It has clock that you can adjust and see how planets move in matter of days, months or years.

[Joe G]

Hi Vlaiv

Thanks for the useful feedback on the way planets orbit in the night sky .I did try to download Stellarium a few years ago but it wouldn’t let me. It was probably an older system but I’ll try it again later . Again thanks Joe 

[Tiny Clanger]

It's never easy to explain such things accurately and simply in words, but ...

Imagine the planets going around the Sun in a series of tracks,  the inner track planets (like us) have a shorter way to go,  so out year / orbit/ circuit is far shorter than the further  out planets . What happens is that we lap those further out planets.

Probably still not clear, so here's a lovely animation to play with, set the speed to one second = a month or faster, tick animate and watch what happens

https://theskylive.com/3dsolarsystem?objs=15p|c2019l3|7p|c2020t2&date=2021-07-01&h=20&m=41&

Heather

[rob_r]

Saturn moved to the right of Jupiter during the Great Conjunction of December 2020. They appeared within a degree, one tenth of a degree if I recall, of each other around the 21st December. Their positions align once every 20 years. 

[Joe G]

Hi Heather & Rob

Thanks for all your feedback. I knew about the Great Conjunction & I should have realised it would result in Saturn “overtaking “ Jupiter. I had a quick look at the Skylive animation & it’s a neat feature in explaining what’s going on up there !! You’ve been a great help in getting my head around it all & again many thanks to everyone Joe 

[skybadger]

4 hours ago, rob_r said:

Saturn moved to the right of Jupiter during the Great Conjunction of December 2020. They appeared within a degree, one tenth of a degree if I recall, of each other around the 21st December. Their positions align once every 20 years. 

I'd forgotten that. It was a sight.