The Moon and dwarf planet Ceres both pass near the Teapot asterism this week. Find out how you can see these for yourself as well as our usual stargazing highlights in this week’s podcast guide, Star Diary, 17 to 23 June 2024.
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Chris: Hello and welcome to Star Diary, the podcast from the makers of BBC Sky at Night Magazine. You can subscribe to the digital edition of the magazine by visiting iTunes, Google Play, or Apple News, or to the print edition by Visiting skyatnightmagazine.com.
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 17 to 23 June. I'm Ezzy Pearson, the magazine's features editor, and I'm joined by Mary McIntyre, an astronomer and astronomy writer.
Mary: Hello, Mary!
Ezzy: Hi, Ezzy! So Mary, what have we got coming up for us in the night sky this week?
Listen to last week's episode – Star Diary: See the Lake of Death on the Moon (10 to 16 June 2024)
Mary: Well, at this time of year in the UK, we don't get very much darkness. In fact, no darkness at all in some parts of the UK, but there are still some interesting things happening, luckily.
So we actually have the earliest sunrise this week and also the summer solstice, they're not necessarily on the same day exactly.
We've got a couple of planets visible, lots of lunar conjunctions which are not dependent on being very dark, and a couple of comets, and hopefully some noctilucent cloud displays as well.
So, first of all the summer solstice. On 20 June is actually the northern hemisphere summer solstice.
That is when the sun reaches its most northerly point as it's basically at 23.5º because of the tilt of the Earth. The sun reaches its highest point from the celestial equator.
So basically, if you plot where the Sun is at its highest point at noon every day throughout the year, it forms an analemma, which is kind of like a figure-of-eight shape.
If you've ever seen one of those, you'll notice that near midsummer the Sun doesn't move an awful lot over those couple of weeks. So that's where the name solstitium comes from, which means Sun stands still. So that's where the name summer solstice actually originates.
Interestingly, the earliest sunrise is not the same day necessarily, but there's only like a minute in it.
So actually the earliest sunrise day is 17 June, but it's only rising one minute earlier. So there's really not a lot in it.
Ezzy: It's not a huge difference. It's not that much extra time you're losing in bed.
Mary: Not really, isn't that? 4:45AM and obviously it starts to get light before the Sun dips over the horizon, which is why we're not really getting any darkness at this time of year.
So yeah, you'll see a lot of stuff online about the summer solstice. I know some people say that stone circles are attuned to the solstices, but I read recently that Stonehenge is more attuned to winter solstice and to the Moon position rather than the Sun. But I think there's a lot of mystery over what those circles were built for and what their purpose was for.
There's a lot of just completely made up stuff about it online. But there will be a lot of people at Stonehenge on the solstice.
Ezzy: Yes, it is definitely there are a lot of ancient structures that are out there that are aligned with the Sun and the Moon because that was the main way people used to tell the time.
I remember writing an article many years ago about an observatory in India, but they didn't have telescopes because they didn't have glass at the time it was built, so instead they built these like huge structures to basically be able to plot out things in the night sky and things like that. So there are a lot of things out there that are aligned with the Sun.
There's also some places which just happen to be aligned with the sun. I know there's a quite famous one called Manhattanhenge, which is, there's a couple of days every year where the east to west streets of Manhattan, the Sun just shines directly down them at sunset, which apparently looks absolutely beautiful to see.
Mary: Yeah, I've seen photographs all the traffic stops and everyone gets out of their cars and it looks absolutely incredible.
So we've got the solstice happening.
In addition to that, we have a couple of planets on show. It's not the best week for it to be honest. Mercury, Venus and Uranus are not visible this week, but the other planets that are visible are primarily morning objects.
So if you look at the eastern horizon around 1:15AM, you'll see Saturn rising. It's about mag plus one at the moment, it lies in Aquarius, so that's kind of the best bet in terms of rising early enough.
Neptune lies to the left of Saturn and rises about 15 minutes later, but being mag +8.5 it's already an object that needs optical aids to see it. And being that near to the twilight is going to make it a challenge to actually spot visually. You might have more chance on a photograph, but visually that's going to be difficult.
Also difficult rising about 2:30 in the morning is Mars. So that's going to be mag +1.1 and lies in Aries. But again, that is going to be a real challenge to spot in the dawn twilight. I do like the challenge of trying to see a planet in the twilight like that, but they are very difficult to get super excited about because it's a tiny speck on a photograph and then it's lost in the twilight getting so bright that it just engulfs it, but it is kind of cool when you do just spot it.
Ezzy: That's one of those things, if you happen to be out at 2:30 in the morning... which you might be, it's the summer, people go out quite late at night. But if you are out and about, maybe doing some stargazing or something, then keep an eye out and see if you can see it.
Mary: Yeah, I mean a lot of us are out before dawn at the moment looking for noctilucent clouds, so do remember that in the east, which is kind of where the noctilucent clouds are likely to be, just keep an eye out for the planets.
Jupiter's rising one hour before the Sun, so you may be lucky enough to spot that, but again, really, really challenging.
Slightly better placed is Ceres, which is a dwarf planet, and that reaches opposition in a couple of weeks, which means it's visible all night. I think we've discussed before, but you don't only get to see a planet at opposition on the night of opposition, it's kind of in the weeks leading up to and after, you can get a really good view of it.
So Ceres is lying near the handle of The Teapot. That's rising about 10:20PM and reaches its highest point about 2:30AM. So kind of in that darkest period that you get, you should be able to spot Ceres. Now you will need binoculars to see that.
Okay, so moving on to the Moon this week. The Moon is passing from around first quarter through to full Moon, which we have on 22 June at 2:07 in the morning.
One thing you may notice if you are an avid Moon observer is that over the winter the Moon was incredibly high in the sky, like the highest it had been for quite a few years. It's now incredibly low again and this is like in a very similar way that the sun is higher in our sky in the summer, the Moon does the opposite.
So the times where the sun is really high in our sky, the Moon is often very, very low. So you need to kind of have a clear horizon because the Moon just doesn't get as high as it used to. But there are still some interesting things to spot. You don't need a very dark sky to observe lunar features.
So on 17 June, Cassini's Moon maiden is visible. This was named by Cassini in honour of his wife Genevieve and it's where the sun rises over Promontorium Heraclides and the right way up it doesn't really look like a Moon maiden but when you look at it through a telescope and it's upside down it really does and it was one of those features I'd photographed numerous times without realising that I had because I was taking pictures of it the right way up.
But that is a really nice one to spot and it's not super time critical you can kind of see it all evening that day and the day after. So that's a good one to look for.
On 19 June at 11:30 at night the 95% waxing Moon is just half a degree above Fang, and that's Pi Scorpii, and that is to the right of Antares. Then the day after the moon has moved over to the left of Antares in Scorpius. So we know Scorpius is very low in our sky, the Moon is kind of moving through Scorpius in those two weeks.
On 22 June we have the full Moon and the libration is favourable to get a glimpse of a couple of features that we don't always see. Because the Moon wobbles as it goes through its phases and through its orbit, we actually get to see about 59% of the lunar surface, not all at the same time obviously, it kind of tips back and forth and wobbles.
And that means that this time we've got the southwestern sort of region, we've got Mare Orientale, which is just visible. That is actually huge. It's 294km across and that lies at the centre of a much bigger feature that's 900km across and it all resembles a bull's eye so it's a massive impact feature and the very centre of it is flooded with lava to form a mare region. Now we can't see all of that lovely bull's eye structure, but we can just get a tantalising glimpse of it and it will be very foreshortened because it's right on the limb. But it is always fun to just get a glimpse of those features that you can't see easily.
Ezzy: I always think when you see something on the edge of the Moon, like Mare Orientale, it really does highlight how much foreshortening there is changes how things seem.
Because as you said from above it looks like almost a perfect circle it's got this entire bull's eye structure and then you see it on the Moon and it's just this kind of long oval thing it's just you would not guess it was circular at all.
Mary: No and I don't know when they figured out that those features were actually circular I guess when they sent probes and got to actually look at them from above.
Ezzy: Well I think people could kind of like deproject it which is... we know it's a sphere so, or sphere-ish, so you know what shape the Moon is, you can just about work out what shape some of these things should be. Then when you go and actually view them from the top, there's all of this detail that you can't see because it all gets squished together when you're looking at it.
It's a thing people tend to forget with a lot of astronomy. Like you were talking about earlier about the fact that most telescopes flip or reverse the image that you're seeing of the Moon because of the way that the light goes through all of the optics. And that's one of the biggest things in astronomy is trying to get what you actually get and turning it into what it actually is.
Mary: Yeah, it's why I'm hopeless at star hopping because every telescope setup we have does something different to the image and it just blows my mind.
Also favourable that night of full Moon is actually Crater Einstein, which is a little bit further up towards the western limb.
And again, that is a nice crater if you see it from above, but it's a kind of squished elongated blob, but it's still nice to just get a glimpse of that. So really good western libration stuff on full Moon night.
On 23 June at about two o'clock in the morning we have the waning gibbous Moon actually lying in the handle of The Teapot. So the Moon actually lies halfway between Namalsadirah II 2 and Ascella, two stars that are within the handle of The Teapot. So we've got a Moon in a Teapot, which is always fun.
We have a couple of comets that you can try for this week as well. 13P Olbers is technically an all night object, as in it's above the horizon all night, but it's pretty low, so your best bet for this is to be out as soon as the Sun is set and just try to get a glimpse of it.
It's moving through Auriga and up towards Lynx this week, so it's only 15º above the kind of northwest horizon after sunset, and it gets lower and lower over night. So given that the north is where all the brighter twilight is, that is going to be a bit of a challenge. It is currently around mag +6.0, but it's +5.0 around about 2 July.
So it is brightening. It may do something interesting. Comets very often do. It's hard to predict exactly what they'll do. But worth looking for that if you are out looking for noctilucent clouds and you're not seeing them, just try to have a look for that comet instead.
Ezzy: That's the thing with comets, you have to hunt them down and sometimes there'll be a bit of a damp squib and a bit of disappointment. But sometimes you'll also get that, where they just suddenly brighten and they're a lot more spectacular than anybody was expecting. And it's that sort of uncertainty I think that a lot of people are drawn to them by.
Mary: Yeah, they don't follow the rules. They really do their own thing, and that is why they're so fascinating. And Comet C/2023 A3 Tsuchinshan-ATLAS is also getting a lot of attention at the moment. That is currently in Leo, so it's about 17º above the west southwest horizon, and that's setting about 1:00 in the morning.
It's currently about mag +9.4, which is definitely going to need optical aids. But it is predicted to get to peak magnitude of -0.9 on 4 October. So all eyes are on this comet. It's going to not be in the most favourable position for us in the UK, but we have a chance to glimpse it now and get some pictures of it.
While it's fainter, then we can compare it as it heads toward perihelion and gets brighter in the sky. And I think it's always fun to get pictures of it before everyone else was talking about it and just see what it looked like and how it did. moves over time.
Ezzy: I knew it before it had an outburst.
Mary: Yeah, you can kind of do little animations and show how it's changing and that's actually really interesting.
It will just be a bit of a smudge, you know, it will be a challenge in the conditions that we have at the moment, but always fun to look for a comet.
So finally this week, we have definitely had confirmed sightings of noctilucent clouds now, so the northern hemisphere noctilucent cloud season is upon us.
To find them, you need to look kind of to your northern horizon about an hour after sunset or an hour before sunrise and low down. Usually from the UK they're pretty low down they kind of have this ethereal glowing quality noctilucent translates as night shining and that is because they're so high up at the border of space and that means they're still illuminated by the Sun when we are in the shadow. It gives them that eerie, ethereal, glowing quality and they're just absolutely beautiful.
So for the most part you do need a low horizon. I don't have big hopes for this year's season because solar activity has been so aggressive recently. We've just had so much solar activity and there's very little water up in that part of the atmosphere and UV light breaks down that water. So the more X-class flares we have, the more energy is hitting our atmosphere, the less water there is to actually even form those clouds in the first place.
So last year was a pretty terrible year. I think I only saw them twice all season. One of them was spectacular. I was in Edinburgh and didn't have a camera, so I had to mark one eyeballs only, but it was really an amazing display. So again, we can't forecast exactly what they'll do, so they're always super interesting to look out for.
Ezzy: Another thing that you raised there was the Sun. The is doing some absolutely fantastic things at the moment. We can't tell you when that's going to happen on the podcast because it's so unpredictable. Most of the time, we don't know a flare is going to happen until it's happening. Occasionally, there'll be a very active sunspot but at most you're getting a couple of days warning. So it's just one of those things people have to sort of pay attention to.
But the Sun is at the maximum point of its 11-year solar cycle. It's due to peak sometime in the next year or so. Various different people predict various different times, but it's approaching the peak, and we won't know until we've gone past exactly when that happened. But keeping an eye on the Sun.
Obviously, as always, when it comes to solar observing, make sure you are looking with the correct equipment, that you're not looking directly with your naked eye. That you've got proper certified solar safety filters on everything, because you can cause quite a lot of damage.
Mary: Obviously when we've got a lot of solar activity, we get more aurora displays from mid latitude. So make sure you've got some aurora apps.
I actually wrote an article on how to forecast aurora for Sky at Night magazine. That's online. It is. So make sure that you're not only finding out about the aurora the day after when everyone's sharing their pictures, make sure you've got the apps and you know when it's happening.
Ezzy: Yes, I will put the link to that article in the show notes below. So if anybody wants to have a look at that, please do.
Thank you very much for taking us through all of that, Mary. And if our listeners at home would like to keep up to date with all of the latest stargazing highlights, do subscribe to the podcast and we will be back here next week.
But to summarise that week again, on 20 June, the northern hemisphere is going to reach its summer solstice, so that will be the shortest day of the year for the northern hemisphere. That does mean some shorter nights, but that doesn't mean there's not lots of things to see.
All of the planets are going to be morning objects at the moment.
Keep an eye out for Mars at around 2:30 in the morning. It's probably not going to be something to get up for especially, but if you are out and about looking for NLCs or something else, have an eye out to see if you can see Mars. We'll also have Jupiter which will rise about an hour just before the Sun as well.
In terms of dwarf planets, we also have Ceres, which will be near the handle of The Teapot asterism.
Looking at the Moon, the Moon's going to be low throughout the entirety of the summer, but on 17 June, you can see Cassini's Moon maiden.
On 19 and 20, the Moon will be near Fang and Antares, bright stars in the constellation of Scorpius.
On 22nd, we have the full Moon to look forward to, which is a great time to look at some of the libration features along the southwestern limb, particularly Mare Orientale, which will be on that southwestern limb.
Then on 23 June, the Moon will lie in The Teapot asterism.
In terms of comets, Comet 13P Olbus is going to be moving through Auriga into Lynx this week, and will be predicted to continue brightening throughout the week, and should be visible just after sunset.
Comet Tsuchinshan-ATLAS will be in Leo and again visible after sunset. Noctilucent cloud season is definitely upon us at the moment, so if you are out an hour after sunset or an hour before sunrise, do keep an eye out for those to see if you can see them.
And finally, also keep an eye out for sunspots and solar flares if you have the proper solar observing equipment as well.
Thank you very much for listening. We always like to hear your feedback, so please do if you have anything that you would like to comment or any questions you'd like to ask, please do email into contactus@skyatnightmagazine.com and from all of us here at Star Diary, goodbye.
If you want to find out even more spectacular sites 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 pullout 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 Night Magazine. Which was edited by Lewis Dobbs. For more of our podcasts, visit our website at skyatnightmagazine.com/podcasts, or head to Spotify, iTunes, or your favourite podcast player.
Listen to next week episode, "When will 'new' star, T Coronae Borealis, appear? (Star Diary, 24 to 30 June 2024)"
