What's in the night sky in the week of 13 to 19 February 2023 in our weekly stargazing guide.


Chris Bramley Hello and welcome to Star Diary, the podcast from the makers of BBC Sky at Night Magazine. You can subscribe to the print edition of the magazine by visiting www.skyatnightmagazine.com Or digital edition by visiting on 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're based here in the UK all times are in GMT. In this episode, we'll be covering the coming week from 13 to 19 February. I'm Ezzy Pearson, the magazine's features editor, and I'm joined on the podcast today by a very special guest, experienced amateur astronomer and photographer Charlotte Daniels.

Charlotte Hello there.

Ezzy Hello, Charlotte. It's so lovely to have you with us. Some of our listeners might recognise Charlotte's wisdom from the pages of Sky at Night Magazine, where she regularly writes for us, and you might even recognise her voice if you've joined one of our online masterclasses, which she was very kind enough to come on and talk to us about and share all of her expertise. And she's going to be joining us on the podcast for the next few weeks. So Charlotte, as I said, it's lovely to have you on. So can you tell us what wonderful things we've got coming up in the sky this week?

Charlotte Thank you Ezzy. It's lovely to be here. Yes, of course. So we are now looking at the period of the 13 to 19 February. And the best thing about this week is that our beloved Moon is starting to wane. So it is starting to gradually disappear for a little while. We do love it. It will be starting off the week at just over 50% illumination and it will be reaching New Moon phase by the following Monday 20th. So we we do just get a slightly well, a slightly a period where it's starting to gradually fade. And it's always tricky trying to take advantage of lovely winter skies during the Full Moon time. So I do think there is this extra eagerness in winter to have it disappear for a little while so that we can get back to some serious stargazing. And so on 13th the Moon will be rising in the very early hours of the morning and it will be setting by 9:45 a.m. so nice and early and it gives us lots of time to observe our beautiful green Comet C/22 E3 ZTF or comet E3 because that is a bit of a mouthful, isn't it?

Ezzy It really is.

Charlotte It really is. So on the Monday evening we'll be able to get our binoculars and our telescopes out and take a good look. So Comet E3 is dimming and it's already had its closest approach and reached its brightest stage for us in the early part of February. But thanks to these dark skies at the waning phases of the Moon, we can definitely still look for and track it in mid-February. Now, so far I've not managed to see it naked eye, unfortunately, but I have been enjoying it through my binoculars in the early morning. Once the Moon has been getting out of the way, I followed it through Camelopardalis. I always have to be careful with that one.

Ezzy It's such a hard one to pronounce.

Charlotte Isn't it? I know. And so I always have to take breaths and. But I also have tracked the comet off to the end of Dubeh in the constellation of Ursa Major. And it's looked absolutely lovely through my pair of binoculars, though I will say that with my trusty 25x70s, it has started to feel very heavy after only 5 to 10 minutes of watching it. So by all means, a smaller pair of 10x50s, for example, will be ample, as we do expect, the magnitude of this comet to still be in that region of 6 to 7 mag at this time around 13 before it gets dimmer in the last half of the month and leaves us. So by the 14 and 15 February, the comet is actually going to be near the constellation of Taurus, which is great as that lovely bright reddish orange star Alderbaran is going to help guide us the way to the comet. So look towards Alderbaran and E3 should be just below and to the left, less than two degrees. So really lovely and close. This could be a perfect time to grab some pictures too. So if you wanted to image the comet per say, you ought to pop a camera on a tracker potentially, and shoot at least with a 250mm lens and 30 seconds to get really detailed shots. However, you can still get really good images untracked and keeping it to about 10 second exposures. All say if you don't want your stars to trail, just make sure you follow the 500 rule. So you would divide 500 by the focal length of your lens and then your stars won't trail too much. Stick all your images together and see what you can get. You could also just take a long exposure untracked and expect trailing stars and you'll still catch lots of detail in your comet because it's moving much, much slower than the stars themselves across our field of view. And so it won't blur. That is the great thing about imaging comets.

Ezzy I think also when you do get those light star trails, it can make some really dynamic pictures as well because you've got this sort of like the motions of the comets tail and then it sort of looks like it's speeding through space.

Charlotte Absolutely.

Ezzy Which it is.

Charlotte Yeah.

Ezzy Even if it's not speeding across our night sky.

Charlotte Exactly. No, you're absolutely right. It gives that kind of sense of motion relative to its background. So, yeah, absolutely. Give give both types of imaging a go. So on the night of 15 February, we'll also get some excellent planetary views this week, just after sunset. The Sun's setting about 5PM that day. So once the Sun is fully disappeared and also give it a good 20 minutes after sunset just to be on the safe side, Look low to the west and you'll see Venus and Neptune very, very close together. You won't be able to miss Venus. It's a real sky hogger. It's our brightest planet and super easy to spot. But Neptune will be as little as 20 arc minutes apart. So barely a third of a degree away from that planet. And it's a nice opportunity to try and observe this distant, distant planet as it's the one that's always challenging to spot. So at least here, Venus can help guide the way on the 15th. And don't forget that night, Jupiter will also be out and all four Galilean moons will be visible. So you can catch this lovely bright planet nice and high by Pisces on the evening of the 15th, too. Finally, on Thursday 16th, when the Moon is just over 30% illuminated and getting smaller. We'll still we'll be able to see the effect of something called lunar libration, which is that orbital phenomenon, which means we don't technically always see one side of the Moon, because that can get boring, can't it? But we occasionally get an extra little glimpse and peek at part of the side that is often hidden. So on 16th, it will be a great time to cast your guess the left limb to see what we call a Southwest lunar libration. And you will see Mare or Sea that we don't always get to look at and this is Mare Orientale, and this translates to Eastern. See, which is kind of counterintuitive because it's actually on the left hand side of the western side of the moon as we see it. But if we could see this sea head on, it's absolutely huge. It's almost 600 miles in diameter and it actually resembles a bull's eye. I wish we could see it head on, honestly. I really do, because it's got these fascinating concentric circles. We're not going to see this face on, sadly, during the libration. However, if conditions allow, we should be able to pick out the mountain ranges around the outer edge of the basin and also appreciate the darker patch of this sea as it partially turns towards us. And you'll have about 2 hours at the early hours of the morning, about 5:30 a.m.. So get get up nice and early. And with sunrise at 7 a.m. You should be able to get plenty of viewing opportunities out of the way of sunrise with plenty of time and be able to see this tiny part of the Moon that we don't get to see that often. So I think that's a really special time.

Ezzy So whilst the Moon is so great to to look at, especially when it's got something special like these libration features, it is moving out of the way at the moment. It is it is making itself scarce. So if somebody did want to take advantage of the dark skies, what is particularly interesting in the night sky at the minute to try and keep an eye on.

Charlotte I just don't think you can beat Orion in winter. I mean, obviously that is Orion's time, but there's something about the different coloured, you know, Betelgeuse and Bellatrix. It has a lovely nebula that's super easy to find as well, the Orion Nebula. M42. You know, I think that that is probably my go to Dark Sky object at this time of year, and it will also be leaving us soon, you know, sort of as we go into March and April, it's it's going to be lower on the horizon before disappearing completely. I really do think that this is a great time to take advantage of it while you can still see the full constellation. Definitely.

Ezzy I know Orion is definitely one of one of my favourites as well. It was the first time I ever saw a nebula was the Orion Nebula, as I'm sure it is the same case for most people and the fact that you can see all phases of like a star's life throughout the constellation of the like the star forming in the nebula and all the way through to Beetlejuice, or Betelgeuse, which is about to explode and go supernova about to and you know, astronomers terms, which is sometime between like now and like 10,000 years time. Maybe. Might be 100,000, you know, order of magnitude it's fine.

Charlotte It's a blink of an eye. The blink of an eye Ezzy

Ezzy It's just several times, you know, history of civilisation. But that's, that's the way it is with astronomy.

Charlotte Do you remember about three years ago when we thought it was about to supernova?

Ezzy Oh, when it started dimming? Yes. I think that was back at the end of 2019, beginning of 2020, I seem to remember. And it suddenly started dimming.

Charlotte Yes.

Ezzy Which they think now it belched, for want of a better term, out a whole bunch of dust. And that knocked the view from Earth and that was why it seemed to them. But it's, you know, people look up at the stars. It's one of the reasons why I really like comets as well, is because they're the kind of unpredictable sides of astronomy, because so much of these things are on millions, billions of years timescale and sort of seeing things happening and changing out there in the cosmos is a fascinating thing to see.

Charlotte Absolutely.

Ezzy And if my listeners at home would like to get to grips with Orion, now is a brilliant time because the Moon is going to be moving out of the way towards the end of the week whilst you're out there. Also keep an eye out for the Green Comet, Comet E3, which is beginning to fade away now, but it is still with us and it is still visible. So definitely worth a look. Then on 15th, it's planet time as we've got Venus and Neptune are going to be very close to each other on the sky. So that'll make it a lot easier to see that dim planet Neptune. Plus, also, Jupiter will be out, joined by all four of its moons. So a great time to try and get out and see those Galilean moons. And on the 16th, even though you might be waiting for the Moon to get out of the way, you might want to take a look at it on 16th as the lunar libration will bring Mare Orientale into view. We also mentioned that one on last week's episode. So if you want a bit more information about that day, be sure to go back and listen to last week's episode. And if you like the episode, do be sure to subscribe. Thank you, Charlotte, for joining us and hopefully we'll have you back on the podcast soon and we'll hopefully see you all here next week. If you want to find out even more spectacular sites that will be gracing the night sky throughout the month, be sure to pick up a copy of BBC Sky at Night Magazine. Well, we have a 16 page pull up Sky guide with a full overview of everything worth looking up for. 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 and Night Magazine. Goodbye.


Chris Bramley 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.


Elizabeth Pearson
Ezzy PearsonScience journalist

Ezzy Pearson is the Features Editor of BBC Sky at Night Magazine. Her first book about the history of robotic planetary landers is out now from The History Press.