Uranus lines up with Jupiter and the Pleiades this week, making it a great chance to see this faint planet. Find out how you can see it and other astronomy highlights in our weekly stargazing guide for 25 September to 1 October 2023.
Chris: Hello and welcome to Star Diary, the podcast from the makers of BBC Sky at Night Magazine. You can subscribe to the print edition of the magazine by visiting skyatnightmagazine.com or to our digital edition by visiting iTunes or Google Play.
Ezzy: Greetings listeners and welcome to Star Diary, a weekly guide to the best things to see in the Northern Hemisphere's night sky. As we are based here in the UK, all times are in BST. In this episode, we'll be covering the coming week from 25 September to 1 October. I'm features Editor Ezzy Pearson, and I'm joined by reviews editor Paul Money.
Hello, Paul.
Paul: Hello, Ezzy. Oh, I hope you like early mornings.
Ezzy: Oh, do we have quite a few early morning starts this week?
Paul: We have a few, and we start with that. But, I mean, it's worth it, because we actually start... we want to catch Mercury. Now, this is the week where it starts to drop back towards the horizon. So we're going to lose it.
But, there's a bit of a slight caveat here. It actually also brightens. So ironically, as it starts to drop down, it brightens, which still makes it easy to actually spot in the twilight sky. So it is in the morning. We're looking about six o'clock in the morning. Venus is to the far upper right, and again between them forming this shallow triangle, we've still got Regulus as well in Leo, the constellation of Leo the lion.
Venus is quite a brilliant object sort of thing, usually about -4.4 magnitude. You know, dazzlingly bright. In fact, if you've got no Moon in the sky, it's worth seeing whether you can do something... It's something that Pete's done. Pete Lawrence has done a few times quite envious of him, 'cause I've never had... I've got all the street lights and whatnot and whatnot, so I can't do it.
But, you could get the shadow of Venus. So basically you put a board up or something and then an object and then you wait. You make sure you do it before twilight sort of thing so that Venus is the dominant. It's so bright it actually can cast a shadow and Peter's done it several times quite amazingly. Peter's done this quite amazingly and been able to capture the shadow cast by Venus.
So it's Venus light hitting an object which then casts a shadow onto a piece of card. Venus is well placed at the moment.
You've got to do it before twilight starts and before the Moon gets into the area, into the morning sky as well. The Moon's in the evening sky, so this is the best week to actually try that, but well worth trying it. So as the ecliptic is quite steep, you know, you've got Venus and you've got Mercury as well.
So we've still got both inferior planets.
Ezzy: And if anybody wants to find out how to cast the shadow of Venus for themselves, we have a guide on that on the website. I will put a link in the notes down below so you can find that if you want to. You will need a very dark sky, as Paul said. But if you want to try, it's always worth a go.
Paul: Oh, definitely. I must say it's one of those projects that... I suppose really I need to go out into the countryside to get a good view, but it's the early morning sort of thing and I like my bed.
Call myself an astronomer. Good grief. Mind you, if it's a very special occasion, I am. I'm good. I do get up. Honest. I do. Honest.
So that was 25th. So, on 26th, I mean... you've got to bear in mind with Venus and Mercury, we have got them most of the week, but watch as Mercury starts to drop down towards the eastern horizon. On the 26th, Let's swap. It's two o'clock in the morning, so not quite as early, but it's still quite late in the night, isn't it?
We have got still Jupiter, Uranus, and the Pleiades star cluster. And again, Uranus is between Jupiter and the Pleiades, and the thing about this is that you will need binoculars, but it is technically naked eye. So if you've got no light pollution, you've got really dark skies, you do want a good chart, which we usually provide in the magazine anyway, and online.
You know, have a go, you might see Uranus, it's better when it's in a blandish area of sky with our... very few stars around it. It's the one that draws your attention to it. In the past, before I had, spectacles, I actually did see Uranus a few times in the naked eye from a dark side. So at least I can say I've got that in the bag. But nowadays I'm afraid it's not the case. Boo! Boo! Oh, never mind.
But have a go, you never know, you might be able to spot Uranus. And I've seen a few friends take photographs of them rising in the morning sky, completely forgetting that one of those dots is actually Uranus. So they're saying, oh, I've got Jupiter and the Pleiades, and I've always wanted to put... And you've got Uranus as well!
Because it's easy to miss it because it isn't as obvious as Jupiter is as well. So yeah, definitely have a look at that and that's on 26th. I mean, it is rising, but it's better to get it higher in the sky sort of thing so that it's a lot clearer and the sky is a bit darker as well. So that's the 26th at 2am.
However... If you go for the later evening, 26 to 27th, you can also see the Moon is creeping up on Saturn. Now, on 26th in the evening, about 9 o'clock, we're looking at the sort of like the gibbous Moon to the lower right of Saturn, and quite a reasonable distance away.
However, if you're one of those that like to stay up all night – he said laughing – then if you watch it before it sets at about 3:20-ish in the morning, so look about 3 o'clock if you've got that western horizon, watch the Moon and Saturn. It's about the southwestern in actual fact.
Watch the Moon and Saturn, because the Moon will be almost in conjunction. It's technically in conjunction shortly after they've set, but the difference to the naked eye is so shallow, you won't notice it.
And it will be a little bit closer to Saturn as well, but it will have changed its position. It will be moving slowly under Saturn. And again, by watching it over a period of a few hours, you're seeing the clockwork mechanism of the Solar System taking place.
You're seeing the Moon slowly move around the Earth. It's very easy from night to night, you'll see it jump. you know, 15 or so degrees, I think, each night. But when you, I always find that when it's close to a planet like this or a bright star, you know, you, you notice the apparent motion more if you observe over a few hours.
Ezzy: I do think, again, that's one of those things that sometimes... in my head, I just imagine the Moon is in one position in one night, and then the next night it's jumped to another place, which, of course, I know that's not what it does at all.
On those nights where you can actually see it, when you have that point of reference to see it moving across, it's actually quite... it's a bit magical.
Realising, as you said, this whole clockwork motion, everything is moving, because so much of astronomy is static, that when you can see these things moving across the night sky... there's a reason why people were always attracted to the planets and the Moon and and so on and so forth, because they were the only things moving across this night sky.
Paul: They were the oddities, weren't they? Sticking with, not quite oddities, but 28th, we're looking at 10 o'clock in the evening, use 10x50 binoculars, look at the Moon, it's not quite full. You might need a telescope to notice it, because it is literally a matter of hours. It's the next morning that it's actually technically full, but it's in daylight sort of thing.
You know, and it will have set for the UK by the time it actually reaches the point of full Moon. But we always tend to sort of be general about full Moon. Usually, when it's about, I don't know... 10 or 12 hours before or after sort of thing, towards this full moon, you know, purists would say, no, there is the point of full Moon and you see it at that point.
But no, in actual fact, visually it can look full for a day and a half either side, you know, because you've got a smaller scale.
Binoculars, I'm not sure whether you'd see any sort of hint of shadowing sort of thing on one edge, it might be... a telescope will, but if you use binoculars on 28th, 10 o'clock, look to the upper right: Lo and behold, there is Neptune and 20 Piscium, in the field of view.
This is interesting because, of course, what we're dealing with is that Neptune was recently at opposition. So, it follows that the Moon will be close to full somewhere in this vicinity, you know, within a week or so. So, I say, it's actually full the next morning, which will place it a little bit further away. But it just shows you the sort of thing.
Because full Moon is actually an opposition Moon. We forget that. It's actually opposite the sun in the sky, so it's full, sort of thing. So it's, we just call it full Moon instead, don't we? Rather than the opposition of the Moon. Because it's just so regular, it happens every single month. But this is a chance to see it. Neptune will be fainter, and of course, you've got to bear in mind the moonlight, very strong, could overwhelm it.
But I think having 20 Piscium there, right next to Neptune as well. If you see a dot next to the star - if you can see 20 Piscium, and then you see a dot next to it, to the right, that's actually Neptune. So, you know, there you are, you've got the two planetary bodies, or two Solar System bodies, the Moon and Neptune, as well as the star.
There might be one or two other stars as well, 27 and 29 Piscium, actually there as well. So well worth having a look at for that. So finally, we've had a bit of a short week this way. Sometimes weeks are like that, aren't they, sort of thing, that there's not as much happening. But, finally, the Moon has moved on.
1 October, it lies to the upper right of Jupiter. So, of course, you've got Jupiter, Uranus, and the Pleiades as well. It's now past full but it will actually lie to the upper right of Jupiter. And if you watch them, this is about 10 o'clock, Jupiter is well above the horizon, so is Uranus They're well above the eastern horizon now, so they are becoming easier and better placed to observe.
We won't have opposition for those planets until a little bit later in the year but we are creeping closer. So they are a lot easier to see. And so the Moon is to the upper right of Jupiter but if you watched again during the course of the night the Moon will slowly move above Neptune so it'll creep closer but move passable Jupiter by the time they set. But by the time they're set, well, that's next week.
So we'll deal with that next week, shall we? So there we are, Ezzy. Lots of things to look out for. Not quite as busy a week, but still interesting nonetheless.
Ezzy: Yes, there's certainly a lot of interesting things to see even if it is one of the quieter weeks, it's still, there's lots to get on with, so thank you very much for taking us through that, Paul.
So to summarise those again, throughout the week Mercury will be visible. It'll be getting brighter as it drops in the sky, and you'll also be able to see Venus as well. On 26 September, Jupiter, Uranus and the Pleiades will form a shallow bowl going across the sky, which makes it a great time to be able to find Uranus, which is going to be right in the middle.
If you want to try finding it [Uranus] with the naked eye, you will need a very good dark sky site, but the Pleiades and Jupiter will help guide you to it. Going from 26 into 27th that evening, the Moon will be slowly moving under the planet of Saturn, which is a great opportunity to see the Moon in motion over the course of several hours.
On 28th, the Moon is just off full, but it will also be in the same binocular field of view as Neptune, so another great opportunity to see one of those dimmer planets.
And then finally, on 1 October, Jupiter, Uranus, and the Pleiades will still be visible together, and the Moon will just appear above it as well, to make a lovely quartet.
So lots to be getting on with this week. We hope you have some good observing, and if you want to find out even more stargazing highlights for the coming weeks, please do subscribe to the podcast, and we will see you here next week.
If you want to find out even more spectacular sights that will be gracing the night sky this month, be sure to pick up a copy of BBC Sky at Night magazine, where we have a 16 page pull out sky guide with a full overview of everything worth looking up for throughout the whole month.
Whether you like to look at the Moon, the planets, or the deep sky. Whether you use binoculars, telescopes, or neither. Our Sky Guide has got you covered, with detailed star charts to help you track your way across the night sky. From all of us here at BBC Sky at Night Magazine, goodbye.
Chris: Thank you for listening to this episode of the Star Diary podcast from the makers of BBC Sky at Night Magazine.
For more of our podcasts, visit our website at skyatnightmagazine.com or head to Acast, iTunes or Spotify.
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Chris: Thank you for listening to this episode of the Star Diary podcast from the makers of BBC Sky Night Magazine. For more of our podcasts, visit our website at skynightmagazine.com or head to iTunes or Spotify.
Click here to listen to the next episode of Star Diary
