That bright star in the south-west

Noticed a bright star over in the south or south-west and wondered what it is? You aren’t alone, and it’s a question that every astronomer gets asked! Could it be the Pole Star, or the Space Station, perhaps?

Jupiter and Saturn as seen at about 20:30 UK time in autumn 2021. Image from Stellarium software

If you are looking in the early evening in autumn 2021, just after sunset, the answer is that it is Venus. You’ll see our closest planetary neighbour in the twilight sky, low down in the south-west. But if you’re looking later in the evening it’s probably Jupiter. During the early evening Jupiter is in the south, but later in the evening, and later in the year, it will be in the south-west. It will be around for the whole of 2021, getting a bit lower in the sky as we go towards Christmas, but with the sun setting earlier each week if you look at the same time after sunset you won’t see much change over the months.

And if you look to the right of Jupiter, about a hand’s breadth at arm’s length, you’ll see another, less bright star. That’s Saturn. By the end of 2021 it will be too low to be seen in the twilight, but if you get the chance, do take a look at it through a telescope and you’ll be able to see its famous rings. How well you see them depends on how good your telescope is – but you’ll see them clearly with a magnification of 40 or more. If you are having trouble getting that telescope to work, check our help page on common telescope problems. The rings look solid enough, but in fact they are made of billions of tiny particles of ice, orbiting in a flat plane around the planet. Probably there are not many chunks bigger than a car within the rings. Many experts believe that the rings are only temporary, so take a look while you can. They may be gone in a hundred thousand years or so!

Jupiter and Saturn
Jupiter and Saturn as they appeared in 2020, when both planets were very close together. View from Stellarium software

And even if you only have binoculars, take a look anyway. Even 10 power binoculars will show that Saturn is somewhat elongated as a result of its amazing rings. The take a look at Jupiter, and you’ll see that it isn’t alone in its journey around the Sun — it has a retinue of four big moons, each of them larger than our own Moon. You might not see them all when you look, as one or two of them might be in line with or behind Jupiter itself. But take a look on another occasion and you’ll find that they have moved, so you might see all four strung out in a line.

During November and December you can see all three planets, Jupiter, Saturn and Venus (working from left to right) in the south and south-west. It will be a gorgeous sight. Look at Venus with binoculars or a telescope and you’ll see that it is a lovely thin crescent, like a crescent Moon but much smaller of course. Venus goes through phases just like the Moon, but it changes size as well, and only when it is very close to Earth, as it is now, can you see the crescent phase.

Fun, isn’t it! To keep up with what’s in the sky, why not join the Society for Popular Astronomy! We believe it’s great value, so find out more here.