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Chris Bramley: 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 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 episode, we'll be covering the coming week from 19 to 25 August. I'm Ezzy Pearson, the magazine's features editor, and I'm joined today by Mary McIntyre, an astronomer and astronomy writer.
So, hello Mary, how are you doing today?
Mary McIntyre: I'm good, thanks.
Ezzy: What do we have to look forward to this week?
Listen to the previous episode, "The Perseid meteor shower peaks (Star Diary 12 to 18 2024)"
Mary: So this week we have a blue moon. We've got Saturn hiding behind the Moon, plenty of planets on show, a miniature bull and a dusty letter E.
Okay, so I'm going to start off with the planets going in order of rise time because they kind of rise at different intervals throughout the night. Venus is still going to be very challenging this week.
It's going to be lost in the twilight, only setting about 45 minutes after the Sun. So despite being the brightest of the planets, you're going to need binoculars to see it. But as we said last week, if you are going to do that, make sure the Sun has definitely dipped below the horizon before you start to look for Venus.
You're not going to see Venus well, very easily anyway, while the Sun is above the horizon. So just let the Sun set for about 15 minutes and then come out with your binoculars and you may spot it low in the west.
Saturn is a bit easier to see. That's currently at mag +0.7. It's lying in Aquarius at the moment and it's rising about 9:30PM in the evening and that is going to then stay visible all night long. It's interesting to look at at the moment because the rings are almost edge on, so it's very pretty to see it that way.
Neptune is rising at about a 9:45PM in the evening. That is at mag +7.7 and is sitting below Pisces, so you will need binoculars or a telescope to spot that.
Likewise with Uranus at mag +5.8, that is in Taurus at the moment and that is going to rise at about 11:30PM in the evening.
So both of those will need binoculars or a telescope. Mars and Jupiter are both still fairly close together after last week's very close conjunction. They're both in Taurus and they're both rising almost at the same time at 12:30AM and then they'll stay visible right through till dawn, so it's a really good time to look at both of those planets.
And Mercury is still lost in the solar glow this week, so we won't be able to observe Mercury this week.
Ezzy: Almost had the full set.
Mary: Nearly, nearly. And when that happens I would notice the press like to say alignment of planets and it's kind of if you've got a sky big enough they're always in a line. It's kind of that's how the orbit works.
It's great to get people out looking for the planets but the graphics they use are always highly suspicious and fake and not really what people will see.
Ezzy: Yes. Do always watch out and we always have detailed charts of where all the planets will be over on our website, skyatnightmagazine.com, as well as in the magazine itself.
So if you do want to know exactly where these planets are going to be, make sure that you check out the website and the magazine.
Mary: While Jupiter's well placed, we have lots of opportunity to see shadow transits, and there is some really good opportunity on 25 August. From about 12:30AM through 2:40AM, you've basically got Io's shadow transiting, and at 1:45AM in the morning, the shadow of Io is going to be on top of the Great Red Spot, so it's always great when those things happen at the same time. From 12:45AM through till 3:55AM, we've got Io itself actually transiting. But as well as that, Europa and Europa's shadow are gonna transit as well.
So the shadow of Europa begins at 2:40AM through to 4:55AM. Then the moon Europa itself will then start to transit the disc at 5:05AM. So with those, although you're gonna start getting twilight, you can still observe them even though it's not fully dark. That's a good night to look at Jupiter because it's all happening with, Europa and Io and the shadows all in the same session. So, it's kind of good.
Asteroid Psyche reached opposition on 6 August, so that is visible all month moving through Capricornus and it's mag +10.0, so you will need optical aids to see that, but I do think it's fun to observe the asteroids. I get excited by those tiny pinpricks of white dots.
I love seeing how they move against the background sky, I just think they're interesting to observe.
Ezzy: It is a bit of a challenge. It's a bit of a quest that you have to really plan out trying to see these things and over a long period of time, but you were talking about there, earlier, but the shadow transit of Io over the GRS and that, I'm actually really keen to see that maybe some people will take like videos of that and you can see the whole journey, but you can see that whole journey in a couple of hours.
With asteroids, that can sometimes be weeks to see they're fully moving across the sky. So that takes dedication.
Mary: Yeah, and I do find those kind of slight challenges, and it's a difficult one because if you're an astrophotographer, the photographs don't have the same impact as taking a picture of the Pleiades or of Jupiter. And people are like, "yeah, it looks like another star, so what?"
But I like it, and I take pictures for myself, not for anybody else, so.
Ezzy: You see that one point of light, that one dot that looks like a very dim, boring star. It's not. It's very interesting, and you will be interested.
Mary: Similarly, Pluto at mag +14.0. You're going to definitely need a big telescope to see it, but that is currently lying between Capricornus and Ophiuchus.
The movement of that against the background stars is minimal, so you really need to observe that over a longer period of time to see it. But it's rising at about 11:00PM now, and it will set at about 2:50AM. So it's reaching its highest point. It's only at around 14º, but that's still high enough to kind of get out of the kind of lower level fug, if you will.
You should have a better chance of seeing it when it's at its highest. So a challenge, but one that that's quite good fun to do.
Moving on to the Moon this week, we begin the week with a full Moon and head towards the last quarter, as the week goes on. And interestingly, the full Moon that we have at 7:25 PM on 19 August is a blue Moon.
There's a lot of confusion over blue Moons, because there are two completely different definitions of what a blue Moon is.
This blue moon is what I consider to be an actual, proper blue moon rather than the newer version that's come to light. There are four seasons in the year and 12 months through the year, so in theory, if the Moon's cycle fitted perfectly with our months, we would get 12 full Moons in a year.
But the Lunar cycle is a bit shorter than that, so every two or three years there will be a season that gets four full Moons instead of three. And the blue Moon is the third of those full Moons rather than the fourth one, so it's the one that's breaking the cycle.
So sometimes it happens that they're both in the same month, so two Full Moons in a month, that is where the newer definition of Blue Moon comes from.
But there's some really interesting things about the origin of the word blue Moon, because the Moon doesn't actually turn blue.
Ezzy: It is very, very rare. There's been a couple of occasions when a volcano has exploded and put ice crystals into the atmosphere. That is a pretty good point, the moon won't actually be blue.
Mary: It won't be blue. The old English word for betray was beluan, and that got mixed up with the word belu in Middle English, which was again for the word blue. So when people were saying betray, they meant betraying the regular pattern of having three, four moons per season. The word betray got mixed up with the old English word for blue, which was belu and therefore it became known as blue.
So it doesn't have its origins in the farmer's almanac like people normally associate with full Moons.
Ezzy: It's one of those important things to remember. The Moon was how people used to track their calendar. It was very important that you could do that. So There suddenly being an extra moon in there was very important for people to know that that was going to come up and why it was such an important thing to keep track of.
Mary: Yeah, and it's that kind of day and a half or two days short of our month cycle basically adds up over time and that's why it's kind of every couple of years. Every two and a half to three years you end up with an extra full moon in the year. That one doesn't have the usual name that we see from the Native American Almanacs because it's an extra one so it doesn't have an official name.
So on 20 August, the 98% waning Moon is going to be just 3º away from Saturn. So if you see a bright star near the Moon that night, that will be Saturn rather than a star.
On 21 August, we have another great event. This time, the Moon is going to actually occult Saturn, so Saturn will actually disappear behind the Moon.
So, the Moon will be a 97% waning gibbous Moon, and this occultation is actually visible across Latin America, the Caribbean, Africa, Europe, and Asia. So we should all get an opportunity to see that.
Now the exact time that Saturn disappears will vary depending on where you are in the country, but the times for the middle of the UK are around about 4:28AM. So make sure that you start observing at least 20 minutes before to just make sure that you don't have the wrong start time and actually miss that because you really don't want to miss the time when it disappears.
The kind of southern part of Saturn will disappear behind the Moon and then when it starts to come out again, it's going to emerge rings first.
So that'll be really exciting to see how quickly you can see those really thin rings starting to appear from behind the limb of the Moon. So yeah, make sure that you're observing in plenty of time so you don't miss those. Yeah, it will be really exciting to see that.
Ezzy: You can always look up, exactly when it's due to be appearing in your neck of the woods. But always with these things, it pays to be there early, just in case you've got something wrong and you put the wrong date into your software or something, or the wrong, slightly wrong location.
You don't want to miss it just because you turned up late.
Mary: Yeah. I mean, if you see it disappear, you've got about 45 minutes before it comes back again. So that means I will be out there 25 minutes after I've been imaging for ages, just waiting for that moment that it just appears again.
So again, because everything's moving along the ecliptic and the Moon and the planets and the stars are all moving at slightly different rates, it's always interesting this game of cat and mouse that happens and it's really great fun to see these sorts of occultations.
They're not rare, per se, but it is unusual to see it from such a huge distance and they're always fun to see, so definitely worth looking for.
Comet 13P Olbers is moving through Coma Berenices, so it's just 18º above the western horizon at 9:45PM in the evening. It's about mag +9.0 now, it will have faded a little bit from last week, so you will need a telescope to see it.
But if you look on 25 August, it's going to be 0.5º away from M64, the Black Eye Galaxy, so having a comet and a galaxy in the same field of view will be a really fun photo opportunity, and good observing opportunity as well, just seeing how different visually the comet looks compared to the galaxy. Because both will just be a little smudge visually, but it's really good fun to look at both of them.
So another thing to look for that's a deep sky object is a beautiful cluster called Poniatowski's Bull. So this is a miniature star cluster that looks like a miniature version of the Hyades star cluster, the V shape and the head of Taurus. If you find Kelb Alrai, which is Beta Ophiuchi, then just scan to the left a little bit, you will see this V shape that's made up of +4.0 and +5.0 magnitude stars.
The stars are 66, 67, 68 and 70 Ophiuchi, so they make that pointing downwards like an arrowhead.
There's an interesting story here. There was an astronomer in the 18th century who proposed that it should be officially named Taurus Poniatowy in honor of the King of Poland, but that didn't happen. But it is known as Poniatowski's Bull because of that story.
If you actually look at this with 10x50 binoculars, you will see that there are way more stars in the background as well as that V shape. It's a really beautiful open cluster, so one that would be really nice to seek out.
Ezzy: That's not the first time I've heard of someone trying to name something in space after a monarch.
Back in the day before government grants and stuff, if you wanted somebody to fund your research and fund your telescope, one of the best ways to do that was to name something after them. But then a lot of the international community said, "No".
Uh, which is why we have the more sort of equal terms that we have today.
Mary: Yeah, proper official naming things, not just random people. I mean, there's still loads of unofficial names for asterisms, but like the official stuff has to go through a board and kind of be properly looked at.
Another interesting thing to seek out is one that's a little bit different because normally we're looking at stars or the shapes they make or clusters they make. And I'm always interested in this ability that the human brain has to see shapes in things that are actually totally random.
This is a great example of that. It's Barnard's E, so it's located in Aquila the Eagle. Altair is the brightest star there, one of the summer triangles, so that's easy to find.
If you just move up a little bit to the star above that called Tarazed, you basically look 1º to the right of that and there'll be this really dense star cloud. But within that dense star cloud, there are some really dark dust areas that kind of spell out a capital E.
If you've got good transparency in your sky, if your sky is not brilliantly transparent, you may see a C with a line underneath it. But just keep looking and hopefully you'll spot the extra bit that's harder to see. And averted vision actually might help you see that letter more evenly.
But I really like things that are named for the dark regions rather than the bright regions. It's something that happens a lot within the Milky Way because we've obviously got the Great Rift and there's all sorts of mythology stories that are named around the dark bits rather than the bright bits and I find that really fascinating.
Ezzy: That's these thick clouds of dust which are just blocking out all the lights of the stars behind it. Unless you manage to get your hands on a very shiny infrared telescope. So, that's why images taken by something like the JWST tend to look a bit different because they just go straight through those dust clouds.
Mary: Yeah, we can't really see through it from here, but it does mean we can look for alphabet letters within the shapes.
Ezzy: Exactly. We can look for all kinds of shapes in those random clouds.
Mary: And on the subject of the Milky Way, because that is kind of nestled within the dust and gas of the Milky Way, we do have another masterclass coming up, a webinar on imaging the Milky Way.
That's taking place on 24 October. So there'll be more information about that on the Sky at Night website.
Click here to buy your tickets to the Masterclass now
Ezzy: Absolutely. And we hope to see more people there. We'll be having an entire suite of classes all about how to take photographs with a DSLR camera. So if that's something of interest to you, please nip over to the website and I will put a link in the show notes below.
Mary: Yeah, there's so much you can do without telescope if you have a camera and you know, there's a whole world out there waiting to be discovered. So that'll be a really great series.
One final thing is that we've got the International Space Station back in our dawn skies from 22 August, so you can have a look on Heavens Above to see the exact times.
There's usually more than one pass in a night and there'll be one that's higher and brighter than the other, but it's always fun to just see the space station silently sailing across the sky.
And on that subject, it's the season where there are loads and loads of opportunities to see the International Space Station crossing the disc of the Moon or the Sun.
Obviously, never try to observe that on the Sun if you don't have the right equipment. But there is a website you can go to. And you need to be within like a 20km channel for it to actually be within the path of visibility, because obviously the Moon is quite small, the Sun is quite small, so you need to be within that path.
But if you go to that website and put your location in and search for the coming month, you will find all the times when it is possible to actually see the space station crossing the Sun or the Moon from where you are. And I, put it in with like a 250km radius and there are so many coming up in the next month.
So it's definitely worth seeking that out and it's amazing to watch because it takes less than a second for the space station to cross the entire Moon and it's just whoosh and it's gone. But when you can actually get a high frame rate video camera like a little CMOS imaging camera. You can just shoot a video of that and extract the frames and you'll see the shape of the space station moving across and that they're challenging, but they are really good fun to do.
Ezzy: Some people managed to get some absolutely amazing shots. I'm constantly in awe that you can see the solar panels and all of these different details on it. It might take a bit of work to get up to that level, but definitely worth trying if you can.
Mary: Yeah, I photographed a few of them and my images are not awe inspiring in any way at all, but the fact that you can even see the H shape with some panels, I'm like, yes! Like one frame out of the 30 will be in focus because of atmospheric turbulence, but it's good fun to do and it'd be boring if we did the easy stuff all the time, so definitely look out for that.
So that's transit-finder.com is the place you can put your details in to look for that.
Ezzy: Definitely lots of interesting things going on, some good challenges as well.
And if our listeners at home would like to keep up to date with all the latest stargazing highlights, please subscribe to the Star Diary Podcast.
And to summarise this week again: Venus is going to be in the evening twilight, but will be quite challenging to see.
You'll have better luck if you want to look at the other planets such as Saturn, Neptune, Uranus, Mars and Jupiter which will be rising throughout the evening.
Take a special look at Jupiter on 25 August where there will be a shadow transit going right over the top of the Great Red Spot.
If you want a couple more challenges, then try and keep an eye out for asteroid Psyche in Capricornus and Pluto, which will be between the constellations of Capricornus and Ophiuchus.
In terms of the Moon, the Moon is going to be moving from full to last quarter.
On 19 August, we will have a full blue Moon. It won't actually be blue, but it will still be worth taking a look at.
On 29 August, we'll have a waning gibbous Moon lying near Saturn.
And then keep an eye out on 21st to see the Saturn being occulted by the Moon in the early morning.
Comet 13P Olbers will be going through Coma Berenice this week.
It's also a chance to take a look at Poniatowski's Bull, a star cluster in Ophiuchus, and maybe even you could also see Barnard's E, a pattern in a dense dust cloud in Aquila, spelling out the letter.
And finally, there's some great ISS passes going on from 22 August. So have a look, see if there's any of those happening in your area, and maybe you'll get a chance to see the ISS going across the sky and perhaps even the Moon.
Thank you very much for listening. Thank you very much to Mary for taking us through all of that, and we'll hopefully see you back here 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, I'm 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.