Watch two comets pass overhead with the help of our weekly stargazing podcast guide, Star Diary 4 to 10 March 2024.
Chris: Hello and welcome to Star Diary, the podcast from the makers of BBC Sky 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 GMT. In this episode, we’ll be covering the coming week from 4 to 10 March. I’m Ezzy Pearson and I’m joined this week by Mary McIntyre.
Hello, Mary!
Mary: Hello!
Ezzy: It’s great to have you back again.
Mary: Thank you.
Ezzy: Please, could you let us know, what do we have to look forward to in this week’s night sky?
Mary: I’m going to start with the planets again, and once again Jupiter is kind of dominating our western sky. But it is starting to slowly dip down, so it won’t be too long before we start losing Jupiter, but it’s still well placed all week this week.
It doesn’t set until about 11 o’clock. So 11:00 at night, obviously. 23:00. And it’s about mag -2.0, so it’s very, very easy to spot.
Now at the moment, if you look at it every night through a pair of binoculars, you will notice that it is moving against the background stars because Jupiter is starting to slip down quite quickly now, and it’s really interesting to kind of compare that with how little, for example, Uranus moves over the space of a week against the background stars.
That is, of course, because Jupiter is much closer to us than Uranus is.
So it’s really easy to spot and on 10 March at 20:30, there is another opportunity to spot the Great Red Spot in transit. It takes about three hours for the Red Spot to transit the full disc of Jupiter. So the kind of bang in the middle is at 20:30.
So you’ll get an opportunity to see the whole of that transit before Jupiter sets.
Ezzy: You said there about being able to see the fact that Jupiter moves more than Uranus.
Mary: Yeah.
Ezzy: It’s stuff like that that always fascinates me because that’s how, you know, ancient astronomers worked out these things were going around us and that one was further away than the other.
And to be honest, when you sort of find out about how ancient astronomers made all of these determinations with just being able to, quite often just looking with their naked eye, I always, it’s absolutely fascinating to me.
Mary: It is. I mean, the name planet is from Planetti, which is the wandering star. They were called the wanderers because they didn’t match the pattern that everything else was following.
Ezzy: Yeah. Exactly. And it’s just that sort of window back into the people who came before us and did all of this work that’s more advanced than I could.
Mary: I get emotional when I actually think back to stuff like that. It can really get to me. It is amazing. Well, if you do spot Jupiter, which is super easy, if you kind of look about seven and three quarter degrees up to the left of that, you’ll spot Uranus with binoculars.
It’s mag +5.8 still. So you are going to need binoculars to see that. And as we just said, if you look at Uranus every day or make a drawing of it through binoculars and get the background star field in there, you will notice that it barely moves in the space of a week, whereas Jupiter does, and I think it’s really fun to compare the two.
Uranus doesn’t set until 23:00, so you’ve got all evening to try to spot that.
Ezzy: And also having something like a big bright Jupiter relatively nearby, it also helps just make sure you’re in the right area of the sky and points your way towards finding objects like Uranus. So hopefully that’ll be a bit of a help as well.
Mary: Yeah, and if you do take just a quick photograph with a simple camera, you will have a star in there that is actually Uranus. When you use Jupiter and just check it against a star map or Stellarium, you’ll be able to find Uranus in your photograph quite easily.
Ezzy: And if anybody does take any wonderful astrophotos this week, please do send them into the magazine.
You can find details in the notes below, and also over at skyatnightmagazine.com. We always love to see your photos, and we will print the best in the magazine as well.
Learn how to photograph the planets by signing up to our Masterclass: Imaging the Planets
Mary: I’m going to talk about a couple of comets. Now, comets are incredibly difficult to predict how bright they’ll be. The famous comet observer David Levy said comets are like cats, they have tails and do exactly what they want, and it is so true.
We’ve got two comets that are well placed, they’re not at the moment super bright, but with binoculars and a small telescope you’ll be able to see them.
The first one is Comet C2021 S3 PanSTARRS. That is visible all week. It’s moving through Serpens Cauda in the eastern sky, so that doesn’t rise until about two o’clock in the morning, so you’ll need to be an early riser for that.
The estimates of the magnitude this will be is a roundabout magnitude. +9.5, so it’s definitely a telescope or big binocular object. But what’s really interesting because comets move even more than any other object against the background sky, especially when they’re near to us, they tend to move through the star field and have lots of conjunctions with deep sky objects.
And on 4 March, PanSTARRS, Comet S3 Pan STARRS, is going to be only half a degree away from Alava, which is a fairly bright star, so that’ll be nice to have those two side by side. And when the comet is near a bright star, it’s actually good to help you find the comet as well. Because comets have a very low surface brightness, so the easiest way to see them is using averted vision, and that is that trick where you look slightly off to one side and the object that you want to see suddenly gets brighter.
That’s because the cells around the outside of your eyes are more sensitive in low light. Therefore, your peripheral vision is more sensitive to faint objects. So, averted vision is an absolute must if you’re doing visual coma observations.
Ezzy: I think it’s the cones which do color and they tend to be focused around the center of your eye. Centre of your retina and around the edge you have the rods which are the bits that sort of say brightness basically like how bright or dim it is and so it’s when you’re using averted vision you’re using more of your rods than your cones.
Mary: Yeah, you don’t really see the colour too much but sometimes when a comet is particularly bright you can see a hint of green colour which is just because of the chemical composition of the comet.
Ezzy: Yes, quite often with most things in astronomy unfortunately the colours only really come out when you start doing photography. But you can occasionally see a hint of colour in something other than a planet, and that’s always nice to see.
Mary: Well, there’s another comet that’s actually brighter than that one, and that’s Comet 12P Pons Brooks.
This one’s been keeping astronomers on their toes for several weeks now because this one is constantly encountering outbursts. So, you have this prediction of what a comet may or may not do, and then it completely throws you a curveball by just saying, “you know what, I’m going to throw a load of gas out tonight and I’m just going to have this really bright coma that’s way brighter than anyone was expecting”, then two nights later it’s all dissipated again and it’s back to where it was.
So if you want to kind of potentially catch an outburst, Pons Brooks is the comet to do it, because it’s constantly doing that. And it will be doing that due to fissures on its surface. And as comets come into the inner Solar System, they’re encountering more solar wind and that is kind of causing sublimation of the materials on the surface.
You’ve got the kind of nucleus in the centre, but then you’ve got that big kind of diffuse area around the outside called the coma. And that will vary in brightness all the time if you’ve got an active comet like this one.
So it’s currently moving across the top of the Square of Pegasus, and that is obviously part of the bigger constellation of Pegasus.
It’s an asterism, but it looks exactly like a huge square on the sky. So if you can find the square of Pegasus, Pons Brooks is kind of moving across the top of that during this week. So it’s about 22 degrees above the west-northwest horizon. Predicted mag +7.5 but take that with a huge pinch of salt because who knows what it will be on the night that you’re looking at it.
Ezzy: It’s one of those things it’s a bit hard to predict, especially when they’re changing from night to night, so always keep an eye on those and look up. If you are interested in seeing a comet, keep an eye on the updates of those to make sure that you don’t miss a particularly good night.
Mary: So moving on to the Moon, the Moon is moving this week from last quarter through to new Moon, so that’s good if you like deep sky objects, but there are a couple of interesting conjunctions with the Moon.
First of all, on 5 March, if you get up early at 5:30 in the morning, 33% waning crescent Moon is going to be resting on the spout of the Teapot Asterism. So Sagittarius, the shape of the constellation, looks a bit like a teapot.
Ezzy: It really does.
Mary: It really does, and there’s a teaspoon up to the top left of it as well, so it’s kind of like, I’m here for the teapot it’s just amazing and it is more of a summer thing really but we can just see a hint of it before dawn at the moment.
Ezzy: Some of the constellations you’re going “that looks like a Centaur? Okay if you say I don’t see it” . But the teapot really looks like a teapot.
Mary: It does and the Moon is pretty much going to rest just on the spout of the the teapot.
So you can get some tea with the Moon in it, which I think is just wonderful. I don’t really do mornings myself, but that’s one that would encourage me to get up and go out and have a look at that.
Now there’s something that the press are undoubtedly going to get hold of, and that is on March, the Moon is going to be at perigee two hours before new Moon. So perigee is when the moon is at its closest to earth because its orbit is not perfectly round, it is an oval shape, so once a month it’s a bit nearer, once a month it’s a bit further away. But whenever there’s a perigee Moon, the press like to call it a supermoon, But this is going to happen on a new Moon.
And I’ve seen before where people have written pages and pages on an article about a Super Black Moon and it’s how to see it. You can’t. So I find it, it’s really weird. We’ve got a Super New Moon. Amazing. Go out and look. Oh, wait, you can’t see anything. And I do find this really strange. The whole obsession with Supermoons is something I find bizarre because to the naked eye, you can not tell the difference.
You can with a telescope a little bit, but. Honestly, the amount of mania that goes on around it kind of drives me a bit crazy.
Ezzy: It’s one of those things where, from my perspective, it gets it into the public consciousness. It gets people talking about the Moon and talking about looking up and into the sky, which I think is a good thing.
Yes, maybe the Supermoon doesn’t actually look any different from a regular Moon, unless you’re taking photographs and comparing them side by side, but if it gets people outside and looking up at the night sky, I don’t think it’s too bad of a thing.
Mary: Yeah, I get it when it’s a super full Moon, but when it’s a super new Moon, it’s a little bit strange to me.
But yeah, again, it’s making people understand the Moon does have phases, and that it is always changing. Like, even in the space of two hours, you can see the shape of the Moon has changed. So yeah, I do get that it’s good to get people going out, but you know, the press are going to get hold of the super new Moon undoubtedly.
So be prepared for the clickbait articles on that one.
Because the Moon isn’t actually rising now until the early hours, basically. It’s a really good time to just kind of have a scan around some other parts of the sky.
And one area that’s really good to investigate at the moment is Orion. Because once we get past another cycle of the Moon, we’re going to be really losing Orion low down in the west. So Orion is a seasonal constellation. We don’t see a at all during the summer and it’s gonna start getting quite low and into the twilight fug, so now’s a really good time to go and investigate Orion with a pair of binoculars.
Obviously everybody zooms in on M42, the Great Orion Nebula, it is utterly beautiful, but If you just use your binoculars and have a look around the belt of Orion, there are hundreds and hundreds of stars. The amount of stars there is just breathtaking when you actually just scan around with your binoculars, so just have a look there.
Like, I know that M42 does deserve the love, but there are other bits of Orion that are beautiful as well.
Ezzy: It’s one of the things I love about Orion is there’s so much going on. You know, you’ve got the nebula, Orion’s nebula. You’ve got lots of other things going on in just the sword region. You can see Rigel, if you want to see a blue giant star, then Betelgeuse up on the other shoulder.
And there’s just whatever you want to look at, you’ll be able to find it in Orion. It’s always a good sort of place for people to start, I think. And everybody knows what it looks like, because it’s one of the first constellations that most people learn.
Mary: It is, and I think I like the seasonal constellations.
I’m sad when he goes, but I’m also happy because I’m starting to see The Teapot and Scorpius. I think Orion is so special because we don’t have him every night. I think you kind of think, oh yeah, Ursa Major, I can see that any time. But when you’re looking at seasonal constellations, it’s… you have to make the most of them while they’re here.
And within the astrophotography community, when we get to the end of summer and towards the winter, there’s this competition over who’s going to be the first to take a picture of M42 this season. People are staying up till 5:00 in the morning to get a glimpse of it before it’s lost again.
It’s worth actually reading some of the mythology stories around Orion.
Not so much the Greek ones, but some of the other stories from other parts of the world are just amazing. So, in your spare time, if you’ve got a bit of free time, just go and investigate some of the stories about Orion because some of them are just incredible.
Ezzy: Absolutely.
Mary: And while the Moon is away again, there’s another cluster that’s worth looking at and that is Messier 93.
This is in the constellation Puppis and it’s called the Butterfly Cluster. It’s one of those rare times where the cluster actually does look like its name. A lot of the names of clusters were given when they were observed naked eye. And when you take a photograph of clusters, you see way more stars than you can visually.
So the clusters rarely look like their name suggests but this one kind of does. It’s really beautiful and it’s really easy to find with binoculars, even though it’s very low down. It is only 15 degrees above the southern horizon, but the star Azmidi in Puppis if you have that in the bottom left corner, the cluster is going to be about in the middle of your field of view.
It’s got +6.0 magnitude overall, but it’s got way more stars around the outside than it does on the inside, which is kind of back to front compared to most star clusters. So it is a really beautiful one to look at.
So there’s another group of galaxies that are worth seeking out while the Moon is out of the way, and that is the Leo Triplet.
Leo is packed with galaxies. Galaxies are usually… like the whole kind of galaxy clusters that we see are located quite far away from the band of the Milky Way, and that’s really good because it means we can see through without having to, you gas and dust obscuring our view of them.
And Leo is in a really kind of empty patch of sky with no gas or dust obscuring things, and there are loads of galaxies there.
The three kind of easier ones to see with binoculars are the Leo Triplet, and that is comprised of NGC 3628, Messier 65, and Messier 66. So, the stars at the bottom of Leo, you’ve got like the pointed nose end of Leo, if that’s the way round you see that constellation.
There is an equilateral triangle between Denebola, Chertan, and TszeTseang (Iota Leonis) and the Leo triplet is halfway between Chertan and TszeTseang so looking at the triangles will really help you kind of get your bearings.
You will need a good dark sky. They are a challenge, but it’s really good to challenge yourself to some of these more difficult objects.
Averted vision is definitely going to help you, and wait until Leo is really high. So kind of have a look at around midnight when Leo is really, really high. Make sure there’s no cloud around and that you’ve got good transparency and good seeing conditions.
And I think it’s really fun to look for the challenging objects because some nights You can see them some nights you can’t and it’s part of the challenge of visual astronomy. I think it’s really good fun to just test that and see what a difference the seeing conditions makes.
Ezzy: Well, it certainly sounds like we’ve got a lot of great things to see in the night sky this week.
So, thank you very much for taking the time out of your day to talk to us about the Mary.
Mary: Thank you.
Ezzy: And if our listeners at home would like to get even more updates about what’s going on in the week’s night sky, do subscribe to the podcast and we will be back next week.
But to summarise this week again.
We started off with the planets.
Jupiter is going to be dominating throughout the night sky this week. It’s very bright and easy to spot and you can even see it moving from night to night across the night sky.
Uranus will also be visible and close to Jupiter this week, so if you need a little bit of a helping hand finding it, that’s the time to go towards Uranus.
We’ve got two comets also appearing in our night sky this week. Comet C 2021 S3 Pan STARRS is predicted to be about +9.5 by around about 4 March when it will be passing by the star of Alava.
And Comet 12P Pons Brook is going to be moving across the tops of the square of Pegasus and that’s been slightly brighter and even having a couple of outbursts so definitely keep an eye on that one and see what it’s getting up to.
In terms of the Moon, this week it will be going from last quarter to new Moon, so there will be some really nice deep skies to be able to see. However, if you want to get a look at the Moon itself, on 5 March, the crescent moon will be on the spout of The Teapot asterism.
And on 10 March it will be a perigee new moon, so just before new Moon it will be reaching its closest approach to Earth. Unfortunately, you’re probably not going to be able to see much with that one.
Whilst the Moon is gone, you also might want to take the opportunity to join Orion before it moves out of our skies.
There’s The Butterfly Cluster as well, which is easy to find with binoculars, and also the Leo Triplet of galaxies will be visible away from the main plane of the Milky Way around about midnight when Leo is nice and high in the night sky.
So thank you very much for taking us through all of that, Mary.
And we hope to see our listeners here back 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.