What's in the night sky in the week of 24 to 30 April, 2023 in our weekly stargazing guide. Mars makes its way through Gemini, while Saturn begins to emerge in the week’s stargazing guide.


Chris Bramley 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 www.skyatnightmagazine.com or digital edition by visiting on iTunes or Google Play.

Ezzy Pearson 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 week's episode, we'll be covering the coming week from 24 to 30 April. I'm Ezzy Pearson, the magazine's features editor, and I'm very glad to be able to welcome back to the show our reviews editor, Paul Money. Hello, Paul.

Paul Money Hello, Ezzy. Glad to be back.

Ezzy It's absolutely great to have you back again. It's been a while, but this week we're looking up at the night sky. Can you tell us what we have to look forward to?

Paul Well, a lot of attention has been in the evening twilight, and that continues because Venus absolutely dominates, doesn't it. I mean, it is so bright. I mean, it's the first thing you never know, see, as the sky starts to darken, but it's got Mars up there as well. But on 24th, we've actually got three planetary bodies. And technically, we ought to say four, because you can see the Earth's horizon. We've got Venus, but we've got the crescent moon as well. It's a rather thick crescent moon, and we've got Mars as well. So, you know, and if you've got dark skies, it's something I haven't I don't really have a good site for because my western horizon has lots of buildings and light pollution. But if you've got a nice horizon you might still get the zodiacal light as well sort of thing. So that's worth looking out for at the moment, especially as it extends through the Pleiades, because the Pleiades star cluster are.. we're in the last stages, we'll lose it shortly after this. So this is your last chance, really, I think, to get the Pleiades and they actually forms a line with.. It goes the Pleiades, M45 Venus, Crescent Moon and Mars. So you've actually got quite a line-up there. And if you have the zodiacal lighting, gosh, you've got a lot going on in the evening sky.

Ezzy For those of you who don't know, the zodiacal light is the light from, I believe, the Solar System. It's dust within the solar system that is gets reflected sunlight. And you can sometimes see it shooting up over the horizon. It does. I believe you need quite a dark sky to be able to see it. But if you are out in the dark anyway, keep an eye out and you might be able to catch it.

Paul Yes, it's a cone of light and it's it follows the ecliptic, which is why we know it's the fine dust in the inner Solar System scattering the light. So I've only seen it a few times to be fair. And you have to get away from light pollution. There's no doubt about it. First time I ever thought I saw it, I was actually looking towards Horncastle and it was the light pollution from Horncastle. So it's just one of those things in it. So yeah, a good dark horizon. So there's nothing in the way. No light pollution to fool you as such, but it does follow the ecliptic and that's part of the clue. So yeah, we've got Venus, the Moon, we've got Mars. We've got the Pleiades as well all in the image. I'm looking around about 9:30pm so I think start to leave early, later and you'll start to lose the Pleiades. But of course the sky will get darker as well. But the Moon is interesting because you've actually got the Moon as a like... Quite thick crescent. And I was I was looking at that and I'm thinking, well, actually halfway between new and half phase. So surely we should be calling it quarter phase Moon. It's just a confusing sort of thing with a normal quarter moon sort of thing, which is of course quarter way around the orbit.

Ezzy I'm quite glad that they haven't gone for that naming convention because the astronomers, they don't always give things the best names. For instance, the quarter moon is when it's half full.

Paul Yes.

Ezzy And then I think having another thing where it's the quarter phase would be even more confusing and I don't think I could have one.

Paul Yeah. So I encourage that to get started, but it does mean we get a good view of the Mare Crisium, the sea of crises actually on the Moon and I always tickles me. Mare Tranquilitatis is just coming into view as well and fecundity art is is well displayed. It's both it and Crisium really well displayed. But it always tickled me that there's a crater called Picard and Mare Crisium and it's actually quite well seen, you know, it's quite an easy one to see, but it's not that Picard. It's not Jean-Luc Picard from a certain TV franchise. No, but it is Jean Picard. And he was actually a French astronomer and geodesist in the Paris Observatory in the 17th century. So, you know, I got to I have to admit, I had to look up geodesist. So somebody who measures the Earth sort of thing, you know, from observations, gets their positions and coordinates from that. So I thought that was quite fascinating. But it's a nice crater. So you've got this huge, great mare sort of thing, but you've also got this nice crater in it. There are all the craters. Well, we should say there are other craters in Mare Crisium and on the Moon. But it's worth having a look up because this one stands out and this particular phase, you've got some nice shadows forming from it as well. So that's the Moon then. Now that's on 24th. So you know, quite a lot happening on 24th. Get started on 25th and 26. What we find is the moons. We always follow the moon that way because the moon, you know, that's where we get months from. It goes round. So every month we're going to have events featuring the moon. And this is no exception because on 25th and 26th and on 25th, it's to the right of Mars. So he shouldn't have trouble identifying Mars really. But it is fading now. So it is beginning to look more like some of the regular stars around it. The only difference is that it is slightly orangish, but Betelgeuse is still up, so you've got the two to compare them. But to give you a guide to it, you've got the Moon on 25th to its right and it's still quite a thick crescent as well. So. So you better pick out Mars. But telescopic it's quite small. Now. I tried imaging it just the other week and it was so tiny and I just thought it's a blob time.

Ezzy Sometimes the planets are just blobs in the night sky, but that doesn't mean you can't, you know, try and pick them out with the naked eye and have a good look at them.

Paul Exactly. I mean, the fact that it shows a disc, there is a disc, there shows you haven't got a star that's out of focus. You've got an actual disc itself. So that was good. The 26th, though, the next night, the Moon is trying to form a bit of a line-up with Castor and Pollux in Gemini. So it's a slightly curved line. And I always think it's a bit of a triangle also with Kappa from Pollux and Kappa Geminiorum as well. So as it happens, with Mars going through the centre of Gemini at this particular time, on 25th, it should be noted it's right next to 48 Geminorum. So it's got a star right next to it. Now, Mars is magnitude +1.3. The star is a lot fainter, it's mag +5.8. So this is quite difference there. You can't confuse them and there'll be a colour difference as well. And you can see this easily with binoculars. You know, technically it's a naked eye star as well, +5.8 magnitude. But you know, but again, you don't want to have much light pollution and you've also got natural light pollution because we've got the Moon coming in and we growing in phase sort of thing. So that's always a... I mean, you either love the moon or you hate it. You hate it if you're a deep sky observer sort of thing, you know, or you love it, If you're a lunar observer. I tend to fall between the two a little bit, but I must admit I am more of a deep sky observer myself.

Ezzy So I think you just have to learn to have to flip flop throughout the month. You know, two weeks you're a lunar observer and then one week you're a deep sky observer and that's how you're going to go through. I think that's probably a good approach to take.

Paul It is.

Ezzy Might require getting some different equipment to use throughout the month.

Paul But often enough, I was going to mention that because if you're an astroimager, once upon a time, when the moon was that was it, you stopped. But now we've got so many different filters that can cut through the moonlight, especially the emission line, one sort of thing, you know, oxygen and silicon, things like that. Astro images now can near enough image throughout the entire month without worrying about the moon. And I think that is absolutely amazing. But it does mean, when do you sleep? During the day? Hang on, you could be a solar observer. And of course, the Sun is actually getting quite active. So, you know, I mean, we have had some recent auroras during March. And, you know, aurora season isn't quite... I've seen aurora in July. I mean, I've only seen it twice. But, you know, if it's a really good storm, you can actually have the aurora during the summer months as well. So, you know, always keep a lookout. You never know if there's a big storm. We are they think now there's a prediction that the solar cycle might peak towards the end of 2023, 2024. So that'll be exciting. So, you know, we might still have some aurora, so it's worth keeping a lookout. Just think, I never, never say it's just a season. So... Just lingering around from March and April, you know, we're thinking about it for the rest of the year as well.

Ezzy I was going to say, if there is anybody out there who is thinking about possibly doing some aurora hunting, you might want to move your plans up a bit. If you are planning on going next year or the year after. People think the peak might happen this year, it might just be that we're in a really active solar cycle and it will keep going on. If you haven't done that once in a lifetime trip, which I, I've managed to go aurora hunting and have success and I really do recommend it if you can.

Paul I mean, it is a sight to behold, I must admit sort of thing. I have a toss up between the aurora and noctilucent clouds. When is Aurora season I'm really excited of a bright aurora and of course, unfortunately I was ill and we had cloud when we had the really bright one in March. Isn't that typical? Isn't that typical. I can't complain because I did do the Northern Lights flights for many years sort of thing. So I got some absolutely humdinger of some displays, but I have seen some great ones from the ground as well. But I have to say sort of thing now, ready one When we get into the summer, my allegiance is switch and I start saying, Oh, yeah,. Noctilucent Clouds. They're brilliant. Yeah. And then when that season finishes, when we get the aurora and get a good aurora. Oh yeah. Well aurora for me. So I'm definitely a flip flopper aren't I.

Ezzy And if you are interested in finding out a bit more about noctilucent clouds, then I suggest you pick up the May copy of BBC Sky at Night Magazine where we have a feature all about in there. And also, if you are interested in hunting aurora or Noctilucent clouds, then go to our website www.skyatnightmagazine.com. We have lots of guides on there. I'll put a couple in the show notes below as well.

Paul Exactly. We will cover it every year slightly because that's just such an amazing experience to see them. And I do know people have gone to Iceland and Norway to see them and being cloud about and I know that really big ones. There was some friends of mine had gone to Norway and didn't get anything and were rather cheesed off, shall we say, to find out we'd had a great display in the UK. Yes, it's an ironic twist, isn't it? Sort of things that you can be up there and actually miss them because the auroral oval has moved south? Otherwise we would better see it in the UK. But you know, it's just one of those things, you know, I mean, you have to take it or leave it. Now, continuing we're looking to the next night,April 27th, we're following the Moon now. We're not quite at half phase. It's just about... it's borderline. Yeah. Catching it directly a half phase is a bit of an art because sometimes it can occur when the Moon's below the horizon for us, but it'll be directly above the Beehive Cluster. This is Messier 44 in Cancer. So the half phase Moon... now the light from the Moon will diminish some of the cluster members. You've got to bear that in mind. And then on the 28th we switch – I know is the morning sky. I know it's 4:30 in the morning, but Saturn is getting back into the sky. Now. You do need a good, uncluttered solar east, south, east horizon, to be fair, which is that I have a disadvantage there. I have an industrial estate and a big... they call it a bund. It's a big sort of a mound that hides us from the industrial estate and got lots of shrubs all over it. Trouble is, as lives have grown up is hidden more and more of that horizon for me. Yet to the great shame but Saturn is now emerging back into view. So you better check out the rings. So yeah, to look at around about 4:30 in the morning. So you know, if you're an early morning riser, you know, a lot of people are they've got work in the morning sort of thing very early. So look out for that. I say in the south, a lot of things are now that Saturn is creeping out to the glare of the Sun. So that was on the 28, sort of thing, and from then on, really sort of thing with Saturn. But on 29th, the Moon continues in a journey around and it's directly involved and forms a bit of a triangle with Regulus and Eta Leonis as well. So but I always find it's almost on a line – it's a bit of a curve – with Algieba and Regulus as well. So Regulus and Algieba both double stars. So this is a time when you can use the Moon to guide you on. Double stars aren't spoiled by the moonlight. That's the good thing about them. Whereas deep sky objects like galaxies and nebulae as a swamped by the moonlight. But double stars are all right. So here we are also Gamma Leonis Algeiba and closer inspection is a closer double with two yellow orange stars, one slightly brighter, and the other one at magnitude 2.21 at 3.6 magnitude as well. So, you know, this is a nice time to catch up on these double stars when the Moon is actually quite close to the Sun. Then to finish off this week, certainly from my part, we've got... Iris, 7 Iris, It is an asteroid. It is actually quite faint, but it reaches opposition on 30th April. It will no doubt is just on the border of Virgo and Libra, both because it reaches opposition, is now visible technically all night, because it rises as the Sun sets and sets to the sun rises. But it is fine if magnitude +9.6. So I would allow at least wait until about 11:00pm onwards, let it get well above the horizon before you try. But you will need, I think, in this case, a telescope to actually hunt it down. So I'll give you another planetary body to find because we have got a scarcity of planets at the moment. We really only got Venus and Mars in the evening sky, Saturn in the morning, and then this very meagre minor planet coming to opposition. We'll have to wait a few weeks, but we will have some come back. Sadly, we've lost Mercury, of course, we've just lost mercury. Oh, we just lost it. It's just one of those things. But it will be back at some stage.

Ezzy It does sort of feel like Venus is doing all of the work at the moment. You know, Venus, it's a bright I think it's about -4.0 this week. It's around about that point. And, you know, very much the brightest thing in the sky after the Moon. And then there might be some other ones maybe.

Paul Yeah. It's almost like screaming out, look at me, look at me. Don't look at anybody else. Look at me. But it is well, it's got the morning and evening star moniker. And of course, at the moment it's the evening star. So it dominates in the night sky and it's the first thing people see as soon as the sky gets dark, so... The trouble is, it's always a bit featureless that. You have to really look carefully and have specialised filters to really bring out the subtle clouds actually on Venus sort of thing. But I like just looking at the crescent, the phase, you know, sort of, gibbous phase at the moment. But it will eventually, later in the summer, turn into a quite large crescent.

Ezzy So to summarise what you can see this week, we start off on 24th of April where Venus, Mars, the moon and the Pleiades will all be lined up on the night sky. Then on 25th and 26th, Mars will be in Gemini, 27th. The moon will be near to the Beehive cluster on 28th. Saturn will be making its way into the morning sky. 29th is a great chance to see some double stars in Leo. And finally finishing up the week on 30th is the opposition of the minor planet Iris. So there certainly sounds like there is a lot of things to see throughout the week. If you'd like to find out what's going to be in the night sky next week and all the weeks after, do be sure to subscribe to the podcast. And thank you very much, Paul, for taking us through all of that.

Paul As a pleasure and look forward to do it next week.

Ezzy Pearson If you want to keep up to date with all of the latest stargazing highlights, do be sure to subscribe to the Star Diary podcast and we hope to see you all here next week. If you want to find out even more spectacular sites that will be gracing the night sky throughout the month, be sure to pick up a copy of BBC Sky at Night magazine. Well, we have a 16 page pull out Sky Guide with a full overview of everything worth looking out for. 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 a detailed star charts to help you track your way across the night sky. From all of us here at BBC Sky and Night Magazine. Goodbye.


Chris Bramley Thank you for listening to this episode of Star Diary, the podcast from the makers of BBC Sky at Night magazine. For more of our podcasts, visit our website at www.skyatnightmagazine.com or head to aCast, iTunes or Spotify.


Elizabeth Pearson
Ezzy PearsonScience journalist

Ezzy Pearson is the Features Editor of BBC Sky at Night Magazine. Her first book about the history of robotic planetary landers is out now from The History Press.