This week, Jupiter’s moons will arrange themselves into a triangle to the left of the gas giant. Find out how you can see it and other celestial sights in this week’s stargazing guide podcast, Star Diary from the makers of BBC Sky at Night Magazine, 1 to 7 July 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 1 to 7 July. I'm Ezzy Pearson, the magazine's features editor, and I'm joined today by Mary McIntyre, an astronomy writer and astronomer.
Hello, Mary!
Mary: Hi, Ezzy!
Ezzy: So, what have we got to look forward to in this week's Night Sky?
Mary: This week, Earth reaches aphelion. We've got an asteroid at opposition, several planets to see, as usual lots of lunar conjunctions and then we have some noctilucent cloud and International Space Station action to look forward to.
First of all, on 5 July, Earth is at aphelion, which is the opposite of perihelion. So Earth's orbit around the Sun is not perfectly circular. And aphelion is the point where it's at its furthest away.
Which is often the opposite way around to what people expect, because obviously it's warmer in the summer. People assume that we are nearer to the Sun in the summer, but we're not. The seasons are caused by the Earth's tilt towards the Sun.
The distance at this time of year is at its furthest from the Sun. And that happens on 5 July.
Ezzy: The reason why it's warm in the summer is because we get more energy from the Sun and the amount of time extra that you get because, you know, the days are longer, we're slightly tipped towards it.
That is much, much more important than the fact that you're... I can't even remember how much closer you are at one time or another. Even though the entire planet is getting slightly less energy from the Sun when it's further away, but the length of time that you're being exposed is much, much more significant.
It's only when you're talking about, you know, the difference between Earth and Mars, that the difference in space becomes much bigger.
Mary: But it's interesting because if you're in the southern hemisphere then aphelion is your winter. Yeah. But in the northern hemisphere it's the other way around.
Ezzy: Yeah, it makes sense if you're in the southern hemisphere.
I remember being in school and when that fact came up and I was like, my brain doesn't compute this . It took me a minute to logic it out in my head.
Mary: It's an interesting one. I mean, the difference is, you know, given the distance as a percentage, it's fairly small. But it, you know, it is a significant difference.
So we have a few planets visible this week, although not being particularly dark still, the conditions are not the best, but we can still have a go at trying to look for them. Saturn is rising about 12:15AM now. It lies in Aquarius and is reaching a magnitude of +0.8, so that should be naked eye visible and rising at 12:15AM, certainly in the more southern parts of the UK you are sort of getting some darkness around that time, so that's a good one to look for.
Neptune is rising about 15 minutes after that, and it's up to the side of Saturn, and that is mag +7.8, so that is definitely something that will need binoculars. If you are taking pictures of that area, just make sure you look for Neptune in the pictures as well as Saturn, because you may well spot it.
Mars lies to the right of Taurus and is rising at about 2am, so that is going to be more of a challenge in the twilight, but is at mag +1.0 at the moment, so you might be able to spot it naked eye, but binoculars will certainly help you out.
Again, another challenge is Uranus, which rises about 2:15 in the morning, and that is in Taurus, so not far away from Mars, and that is at mag +5.8, so although that's still brighter than Neptune, it is more in the twilight sky. So again, it's going to be a challenge. Certainly you're going to need binoculars for sure to see that.
Jupiter is definitely going to be a challenge because of twilight, but it is improving. It's currently rising at about 3:00AM and it's about mag -0.2, so it is bright, it's just competing with the twilight sky. Now, interestingly, on 4 July, it's just 5º north of Aldebaran, so it'd be interesting to try to spot both of those in binoculars and see if you can find where they both lie.
On 6 July, if you look at Jupiter with binoculars, you can see the Galilean moons.
The Galilean moons don't orbit Jupiter in a perfect kind of plane, so sometimes the moons are a little bit higher than at other times, and there's a really interesting kind of pattern that it makes on this particular night.
You've got Io, Europa, and Callisto forming a big triangle to the left of Jupiter, which is something that I don't see particularly often, so I thought that was quite interesting. And you'll have Ganymede off to the right, but you'll have this really clear triangle of what looked like a triangle of stars all grouped together on the left of Jupiter.
So hopefully you'll be able to spot that in the twilight, definitely worth looking for on 6 July.
In the evening we have two planets that are very, very low after sunset, so these are going to be a challenge.
First of all, Venus. Venus lies in Gemini, and that is technically mag -3.8, but it sets at 10:00PM which is just 30 minutes after the Sun. So it certainly is not going to look like it's mag -3.8. It really will be a challenge, it's going to be very, very low.
So if you are trying to spot these, please wait until the Sun has set. Don't try to look for these planets in the evening sky until the Sun is well out of the way because you do not want to accidentally point your binoculars at the Sun. It's so important that you don't do that.
Ezzy: Especially when... the second that you start involving binoculars or telescopes. You shouldn't look with your naked eye, but I know everybody does, but don't. But the second that you pick up a telescope or a pair of binoculars, you need to make sure that the Sun is out of the way.
Mary: Also very low in Cancer, setting at around 10:30PM we have Mercury, currently at mag -0.7, but again, very low in the twilight. Will be a bit of a challenge, but they are there, so I want to tell you that they're there, just so you can try to find them.
Dwarf planet Ceres reaches opposition on 6 July, so that is visible all night. It is located within The Teapot asterism. That is mag +7.3, so you will need binoculars to see that.
But it is easy to see in binoculars, and later on in the night we are actually getting some darkness now, so it will be okay to spot.
It's rising at about 10:00PM. But that will obviously be in the twilight, but it's getting maximum altitude of 8º at about 1:15AM, so if you kind of try to look for it before that, before it gets it maximum height, you will have it when it's still quite dark.
So that is low, but The Teapot is low from the UK, like there's nothing we can really do about that, that's just where that constellation lies.
Ezzy: But maybe if people are going off on their summer holidays, that might be something to keep an eye on.
Mary: Yeah, if you're heading further south, it'll be higher in the sky, but if you are anywhere on high ground that has a clear view that direction, you'll have no problem spotting it.
So moving on to the Moon, this week we've got the Moon passing through from a waning crescent phase down to a new Moon on 5 July, then at the very end of the week, the Moon is waxing again. So it's quite an interesting time to see the Moon switch from our morning sky to the evening sky and changing its appearance quite drastically.
On 1 July, the 26% waning Moon is going to be to the upper right of Mars. Then the following day, it's now a 17% waning Moon, that's going to be to the left of Mars.
So again, the kind of celestial cat and mouse thing going on. One day it's to one side of a planet, the next day it's at the other. So, it'll be really good for helping you find Mars, actually, because you can use the Moon as a bit of a pointer.
On 3 July, the 9% Moon is just 4.25º above Jupiter. Then you've got M45, the Pleiades to the upper right of that, and you've also got Uranus and Mars to the right. So that's quite a grouping of quite a few objects that you can try to look for and use the Moon as a a pointer again to try to find those.
On 4 July, the 4% Moon is just 3º to the right of Elnath. So I always find that the really slender Moons are more difficult to spot, but that they are in fun challenge.
Now, this one is a challenge On 5 July, a 1% waxing Moon is gonna be just 3.3º above Venus. So you can use Venus to help you find the Moon because spotting a 1% Moon in a not pitch black sky – almost impossible. So if you can find Venus, you can use it as a pointer to try to then find that very, very slender Moon.
And obviously being 1%, it's going to set quite soon after sunset. So it's going to be low in the sky. Venus is low in the sky already. The Moon is going to be very low, but that'll be a fun one to try for. It will be a challenge.
On 7 July, the 3% waxy Moon is just 2.2º above Mercury, so this time you can use the moon as a pointer to try to look for where Mercury is. A 3% Moon is a lot easier to spot than a 1%, so you'll have more chance of doing it that way round on 7th.
Ezzy: Does look like the Moon is taking its tour of the planets this week. Mars, Uranus, Jupiter, and Venus and Mercury.
Mary: They're all along the ecliptic and most of the planets are in the dawn sky at the moment, so the Moon is just moving through all of them.
They're not actually near each other, we just must point out, that it's just the way that they look from here. They're not really near each other. I see some crazy stuff online about that. No, it's just line of sight effect.
Ezzy: They are close to each other on the night sky.
Mary: Night sky, yeah. Moving on to comets, these are both a bit of a challenge now. 13P Olbers is technically an all night object, but best after sunset.
It's moving through links and it's about 17º above the northwest horizon at 11:15PM. It's then sinking lower and lower as the night goes on. It doesn't set, but it gets lower and lower in that twilight, so your best chance to try to find that is as soon as it gets dark after sunset. It is predicted to reach peak magnitude this week on 2 July, where it will be around about mag +5.0.
I don't think you will see that naked eye in the twilight, although technically that figure is on the verge of naked eye visibility. I think you're going to need binoculars, but definitely have a look for that. And if you do spot it on 6 July, it's just 23 arc minutes from Ursa Majoris. Which is a binary star system which is in Lynx, even though it's got the name Ursa Majoris.
The constellation boundaries were changed, so the star is still named as though it belongs to Ursa Major when it's no longer in Ursa Major.
Ezzy: It's always good when they make sure that star names are nice and easy to understand so that you know exactly what everything's going on. You know, sometimes they call things like noctilucent, night shining, very nice and easy to understand, and then they do something like that.
Mary: I'm trying to remember, was it in the 20s where they changed all the constellation boundaries and made it a formal map of regions rather than just the stars that formed the brighter bits of the constellation? So the definition of what a constellation is very subtly changed, but they did change the boundaries there and that means that some of the stars that used to be in Ursa Major are no longer in Ursa Major.
But yeah, that is a very close conjunction of that comet and that star, so it's worth having a look for that one.
Ezzy: So yeah, with the constellations. There's the constellation in terms of the star pattern that we see out in the night sky that people have been using for millennia to keep track of and the things with all the stories associated with it.
And there's also a constellation, which is an area of sky, which is roughly blocked out around those various star patterns. That's, you know, prescribed these days by the International Astronomers Union. It's used to show different areas of sky, split up the sky into 88 different sections. Very unevenly.
It's very much a higgledy piggledy pattern out there on the night sky, but it's what astronomers use to find their way around.
Mary: Yeah, I find those irregular boundaries really frustrating sometimes. It's like, why does that one extend out and go down there for no apparent reason? I'm sure they had their reasons, I wasn't on the committee.
But yeah, it does have a different definition now, and it's good that we do have those formal boundaries. They went with the Greek Roman breakup of the sky, different cultures broke the sky up in a different way entirely. So yeah, I still love looking at star mythology from other cultures other than the Great Roman stuff.
It's fascinating to see how differently they interpreted those patterns.
Ezzy: I mean, there are some in, especially in the Southern Hemisphere sky where, partly because there weren't as many people living in the Southern Hemisphere, so there's a lot of bits of night sky that didn't really have people telling stories about it.
I know there's the Sextant constellation, and I think there's a Water Pump as well, and all of these...
Mary: Microscopium.
Ezzy: Ones that are named after various different scientific instruments because that was what people wanted to record at the time that the constellations were made.
Mary: Yeah, it's a fascinating thing to delve into. There are so many amazing books on that subject. But yeah, it is interesting to actually see a star with apparently the wrong name. But it's going to be very, very close to the comet that night.
We have C2023 A3 Tsuchinshan-ATLAS that is currently below Leo. That's going to be visible after sunset. On 1 July it's only going to be 5º above the west horizon at 11:15PM, so that is incredibly low. Very difficult to see anything that low because of atmospheric turbulence you're seeing through a thicker layer of atmosphere. You get more distortion effects and it makes things more difficult to see.
But unfortunately that is where it is. It's setting by midnight.
By 7 July, by the end of this week, it's only 1.5º above the horizon at 12:15. That's going to be tough. That's going to be almost impossible to see. So although there are a lot of eyes on this comet because it is predicted to get a lot brighter later in the year, like possibly mag -1.0 by October,
it's currently mag +9.4, so you are not going to see it through that many layers of atmosphere. It's just really unfortunate that it's not well placed for us anymore here in the northern hemisphere, but if you can quickly get a glimpse of it at the beginning of this week, it'd be interesting to compare with what it's going to look like later in the year, if it does brighten as much as they think it will.
So noctilucent cloud season continues throughout July. These are night shining clouds. They are absolutely minuscule ice crystal clouds which are right upon the edge of space and they are so high that they remain illuminated by the Sun.
At this time of year the sun does dip a bit lower so there's less chance that they're going to be visible all night long, but if you look around an hour after sunset, hour and a half after sunset, look towards the northwest horizon and then through the night as the Sun dips.
Any clouds that are there will remain illuminated. You sometimes see them look like the clouds are moving along the horizon as the Sun moves. It's just that's so small, those ice particles are so so small that they just catch a glimpse of the sun when it's in the right position.
So they are very, very beautiful. I don't love getting up early at all, but I will do it for Noctilucent Clouds. I'm not a morning person, as everyone who knows me will attest, but I really do love Noctilucent Clouds and it is genuinely the only time of year that I ever see dawn.
It's kind of nice that if I'm out there, then I will look for the planets and other things as well. If there's no Noctilucent Clouds, I will not be out at dawn. But they are really, really beautiful. And I think a lot of people
once they have seen them, they understand why people get quite obsessed with them because they are very beautiful. They make a beautiful time lapse subject. They, they move in a very different way from clouds in our lower atmosphere.
It's kind of like they're influenced by gravity waves. You end up with like water ripples. You can have interacting spirals moving along. There are so many different subtypes of noctilucent clouds. Each of them more beautiful than the other. And when you just even do 20 minute time lapse, you can see that they're moving slowly in just such an interesting way. They behave so differently from normal clouds.
Finally, the International Space Station has got some really good passes all week during the early hours of the morning. There are multiple passes through the morning because the ISS goes all the way around the Earth in less than an hour and a half. So you quite often get two chances.
One of them will be higher than another and brighter than another. So definitely look out for the times for your local area for that if you are in the UK, because it will be the brightest thing in the sky other than the Moon for that brief time that it's visible. So always fun to watch that and wave at the astronauts that are on there and do #ISSWave on Twitter.
Ezzy: The ISS is very bright. I've seen it go overhead a fair few times. And we've had some absolutely amazing images of people managed to take of them. There's a lot of astrophotographers who actually managed to, you know, you can make out the solar panels from a picture, which just blows my mind a little bit that you can get that much detail.
Mary: I've tried that. It's so hard. You need five arms. It's just, I don't know how people do it by themselves. Like two of us have done it together trying to capture it and we still struggle.
Ezzy: Because that's the other thing, when it's that zoomed in to be able to make it up, then it goes across the field of view within moments.
It's so quick. You need to really make sure that your telescope's in the right place to get that. So it's always very impressive when people manage it.
Mary: It really is. There's some of them I'm kind of like, is this even real? But you can see that the tilt is correct and yeah, it is awesome. But even with the naked eye from a light polluted area, you will see it because it can reach like almost mag -4.0 when you've got a good pass.
So even from the most light polluted city, you will be able to see that. So it's always good fun to look for that.
Ezzy: Well, thank you very much, Mary, for taking us through all of those. And if our listeners at home would like to make sure they keep up to date with even more stargazing highlights coming in the future, please do subscribe to the Star Diary podcast and we will see you back here next week.
But to quickly summarise this week again.
We start off with looking a little bit at the Earth, actually. Earth is going to be at aphelion, its furthest distance from the Sun on 5 July. In terms of the planets, Saturn will rise at around 12:15PM, Neptune around about 12:30PM, Mars and Uranus will both be rising at around about 2:15AM, Jupiter at about 3:00AM however, those later ones will be towards the twilight, they will be quite low down in the sky. They will be trickier to see, so do be aware of that.
However, on 4 July, you might want to try and make the effort to find Jupiter as it will be near the bright star Aldebaran.
And on 3 July, the Galilean moons, Jupiter's moons, will form a triangle to the left of Jupiter. Or at least three of them will, with Ganymede off on the right hand side as well.
In terms of the evening sky, we have Venus, but that will be setting at 10:00PM very shortly after the Sun is setting, and Mercury setting at 10:30PM as well. So again, those two will be a bit trickier to see.
The dwarf planet Ceres will be in The Teapot asterism throughout the week from around about 10:00PM but will be reaching its max altitude at around 1:15AM.
In terms of the Moon, it's taking a tour of the planets this week. We start on the first and the second, where the crescent Moon will be passing by Mars.
On 3rd, it will be meeting up with Jupiter, M45 Uranus and Mars, so great opportunity to see five different things together there.
On the 4th, it will be near the star Elnath. 5th, the 1% waxing crescent will be very difficult to see, but you will be able to catch that near Venus on 5th. And then finally, on 7th, it will be near the planet Mercury.
In terms of comets, 13P Olbers is still in Lynx. It will be up all night, but best viewed after sunset. Its peak of brightness is predicted to be on 2 July, however it will be in twilight, so it might still be quite tricky to see.
Comet Tsuchinshan-ATLAS will be visible from 1 July just above the horizon at about 11:15PM but it will be incredibly low, getting even lower by 7 July it will just be 1.5º above the horizon. But you might still want to try and get a look at it now so that when it does brighten up significantly later in the year, as it's supposed to, you will have some for your reference to come back to.
NLCs should be visible about an hour or so after sunset or before sunrise throughout this week and going forward into the next couple of months. So do keep an eye out for those.
And finally, the International Space Station is due to make several good passes above the UK this week, so do be sure to look out when that's going to be going overhead in your area.
It will be very bright in the night sky and should be easy to spot, so something to look forward to there as well.
And if you do manage to catch any of those sites, please do let us know at contactus@skyatnightmagazine.com. We always like to hear what you found and what you've seen and what you've imaged in the night sky as well.
So thank you very much for listening and we hope to see you all here back next week. From all of us here at Sky at Night Magazine, 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 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, 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.
