Noctilucent, or night shining, clouds sparkle from the edge of space in the twilight sky. Find out how you can see these for yourself as well as our usual stargazing highlights in this week’s podcast guide, Star Diary, 27 May to 3 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 skyatnighmagazine.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 27 May to 2 June. I’m features editor Ezzy Pearson and I’m joined this week by astronomy writer Katrin Raynor.
Hello, Katrin!
Katrin: Hi Ezzy.
Ezzy: So Katrin, what do we have to look forward to in this week’s night sky?
Katrin: Okay, there are a few things to look for and enjoy. So this week we have a waning Moon and two planets visible in the dawn sky, as well as a binary star to point your telescope at. It’s the start of a new month and any fans of noctilucent clouds who enjoy taking photos of them will be dusting off their cameras as I speak.
It’s a really exciting time for these cloud hunters or for any listeners who have just tuned in and may not have heard of them before or, you know, seen them before. I’m hoping that some beginners will get out and try and spot some.
So on that note, I am going to start with noctilucent clouds or NLCs.
So we’re now entering noctilucent cloud season or NLC season as we approach the end of the month and enter June.
Now these clouds appear from the end of May right through summer to the beginning of August. And the clouds don’t actually occur in space but instead in the high altitudes of Earth’s atmosphere, the mesosphere, at around 76 to 85 kilometers from Earth’s surface.
And they don’t appear in the daytime sky, which you might think is quite weird.
They are composed of ice crystals and can be seen during astronomical twilight, so between sunset and sunrise from mid latitudes, as the sunlight reflects off the ice crystals which make up the clouds. And now the clouds are just really beautiful, they’re blue white swirls, they look totally magical in the twilight, and in fact the name means night shining, so noctae meaning night and lucent meaning shining.
Have you seen them before?
Ezzy: I think I saw them once. I keep an eye out for them. Unfortunately, my garden points the wrong way.
Katrin: Oh. Typical.
Ezzy: And I live in a very built up area, which doesn’t help. But I think I saw them once. They were very, very pretty. I was very… I was annoyed I didn’t have my camera on me at the time.
Katrin: Oh, yeah. You’ll have to try this summer, perhaps.
Ezzy: It’s one of those things I do sort of keep on my radar and I keep an eye out. But it requires remembering when sunset is, and I’m not great at that. I suddenly look outside and it’s dark.
Katrin: Yeah. Now, unlike meteor showers or comets, there is no specific date or time that the NLCs will make an appearance.
So you’ll want to utilise any clear night that we have to try and spot an NLC display. You’ll want to look to the northwest horizon around 90 to 120 minutes after sunset or before sunrise. And on a good night, these displays can be seen all night long. Now, I’m yet to spot an NLC display. I think, you know, like you were saying, Ezzy, from your location, it’s hard.
And from my location, it’s difficult because I live in the South Wales Valleys. So, you know, I don’t really have a clear horizon at all because it’s just hills everywhere you look.
So yeah, you know, I think it’s going to be worth me taking a trip out in June to a location with a clearer horizon to try and spot some.
You know, I’ve seen some fantastic photographs of NLCs, and I do know that a close astronomy friend and writer for the Sky At Night, he’s a huge fan. Gets very excited during NLC season, so I look forward to seeing his pictures.
Ezzy: I know a lot of astronomers get really excited about NLCs because they do tend to occur at a time of year when it’s not really getting properly dark, you can’t necessarily see what’s going on in the night sky as well as you might hope. So it’s something else to get you out and looking up at the night sky.
Katrin: So diehard NLC observers utilise satellite images and data to predict when the NLCs may be happening. But sometimes it is just the anticipation of spotting them that I think beginners may enjoy and you know just getting out on a clear night and seeing them will be totally rewarding.
And the best part of all is you don’t need any equipment to see the clouds. Just get out to a location with a clear north west horizon and look up, and this could even be from your own garden. But remember, even in June, the nights can be chilly, so make sure you are wearing some warm clothes.
Ezzy: Also, on that safety point, if you are going out somewhere to try and get a clear view of the horizon, make sure it’s somewhere that you’re allowed to be after dark.
Make sure that you can find your way back in the dark as well.
As you said, it’s still summer. It still does get dark at night, even if it doesn’t get as dark as some astronomers might like it. So just make sure protect yourself when you’re coming home as well.
Katrin: Okay, so moonrise, we start the week off with the Moon rising after midnight, and as the week goes on, it will rise later and later.
So we’ll be seeing the Moon mainly in the daytime sky, which is great news for any listeners who want to enjoy the moonless nights. Well, a moonless night at this time of year is greatly appreciated because as you know, and as we’ve said earlier, the nights, they’re a lot lighter than they are in winter, for example.
Ezzy: You don’t want to be dealing with the Moon and a summer night if you’re trying to see something particularly deep in the sky. You can’t change the time of year, but you can at least wait until the Moon gets out of the way.
Katrin: So on 31st there will be another fantastic photo opportunity. When on the morning of 31st, the Moon and Saturn will be close together, rising in the East at around 3:00AM.
The Moon will be 45% lit at this time, and Saturn will be shining at a magnitude of around +1.0, so you know, pretty bright. You’re going to have around two hours of observing time before the Sun rises, which is five minutes earlier than last week at 5:02AM. Solar System wise, Mars and Saturn are in the morning sky all of this week.
Mars will rise around an hour and 40 minutes before the Sun at 3:30AM, low in the eastern horizon, while Saturn will have risen around 2:45AM. And if you want to view Mars a bit later on in the dawn sky, remember never use your binoculars or any optical aids to look at the Sun, so view with caution. And we do mention that quite a lot when the Sun is in the sky close to a planet, just be careful.
Ezzy: We do keep saying it every time it comes up and we will keep saying it because it is very important. We don’t want anybody to hurt their eyes because then you wouldn’t be able to see all the wonderful things coming up in the night sky. So protect them and make sure that you’re being careful of where the Sun is.
Katrin: So, Comet C/2023 A3 Tsuchinshan-ATLAS has now moved out of the Bowl of Virgo and is slowly making its way towards Leo the Lion, located in the southwestern sky. And on 1 June, the comet will be shining at a magnitude of around +9.0, so again, nowhere near naked eye visibility, but it can be picked up in small telescopes.
If you have a digital camera with a long lens, you know, have a go at photographing it. For any budding astrophotographers, this would be a great time to start snapping the comet over the coming weeks and months. You know, maybe creating a montage over time to show how it brightens and changes in appearance.
Ezzy: And if anybody is interested in learning how to photograph comets and learning a bit more about that, we have a guide over on our website. I’m going to put a link down to that in the show notes below as well. So if you want to get a bit more up to date with how to photograph a comet, take a look there.
Katrin: So as we approach the end of May, now is a good time to focus your gaze on the constellation of Boötes or Boot-ies, the Herdsman. So Boötes features the fourth brightest star in the night sky, Arcturus. It’s one of spring’s prominent stars shining in the night sky, an approximate magnitude of +0.11, so yeah, just above +0.0 so it’s really bright.
Boötes sits above the constellation of Virgo, and whilst this constellation contains very few objects to view, Izar, a double or multiple star, is worthwhile pointing your telescope at.
So if you can locate Arcturus, and if you draw an imaginary line with your eyes diagonally upwards to the left, until you settle on the nearest brightest star, you have found Izar.
And a telescope with an aperture larger than three inches will actually separate the double stars which appear as one yellow and one blue star. So something really worth taking a look at, I think, towards the end of May.
Ezzy: There is something quite fascinating about looking up in the night sky and seeing something as one thing and then you look through your telescope and you see it as a completely different thing.
And with binary stars that’s one of those things that when you look at them separately it’s what seems to be one white star is actually two coloured ones and it is just really interesting.
Katrin: Yeah, I’m going to give this one a go as well, I think, with the telescope I bought last year. So, yeah, it’s like you say, I think when you are just looking up with the naked eye, it does look like one star, but once you use an optical aid and it’s magnified, you think, oh wow, yeah, I can see two things rather than one.
So yeah, I’ll be giving this a go.
Ezzy: And there are some systems out there that actually have multiple stars, more than two. Finding three is quite common, but there’s been two systems that have seven stars within them, all stably balanced together, and those are Ai Cassiopeiae and Nu Scorpii. So those two star systems are actually made up of seven different stars all orbiting around each other.
Thank you very much for taking us through all of those, Katrin. And if you at home would like to get even more stargazing highlights, please do subscribe to the podcast and we’ll be back here next week with even more highlights.
So, to summarise this week again, though:
We start with taking a look at noctilucent cloud season, which will be kicking off from late May throughout June, and will carry on right through the summer until the beginning of August.
There’s no specific time or date when you can see these. You’ll want to make the most of any clear evenings that you can to get out and try and spot them over the northwestern horizon. They’ll appear about 90 to 120 minutes after sunset or before sunrise, so that’s when you want to be looking for those.
In terms of what’s going on in the Solar System, in the morning of 31st we have the Moon and Saturn which will be close together and rising in the east at around 3:00AM.
Mars and Saturn are in the morning sky all this week. They’ll be visible low above the eastern horizon. You will need an unobstructed view to be able to see those, they are quite low.
Comet C/2023 A3 Tsuchinshan-ATLAS has now moved out of the Bowl of Virgo and is slowly making its way towards Leo the Lion, which is located in the southwestern sky. It is still quite faint, so you’ll need a large or small telescope to be able to see that comet.
And finally, if you point your telescope at the double star Izar in Boötes/ Booties then you will be able to see that it is actually two stars, one yellow and one blue star orbiting around each other.
So lots of really fascinating things to see in the night sky this week and hopefully we’ll see you back here next week for even more. Goodbye.
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 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.