What's in the night sky of the week of 16 to 22 January 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 skyatnightmagazine.com or digital edition by visiting on iTunes or Google Play.

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 GMT. In this episode we'll be covering the coming week from 16th to 22nd of January. I'm Ezzy Pearson, the magazine's features editor and I'm joined on the podcast today by reviews editor Paul Money. Hello Paul.

Paul Money Hello there is now a back to normal now for this week aren't we? So quite a few events to look out for.

Ezzy Yes. So what do we have to look forward to over the coming week?

Paul Well, we did mention that Mercury would have a poor apparition over the last few weeks. We mention that. But Mercury does creep into the early morning twilight sky. So we're looking from 16th onwards, but it isn't a particularly good appearance. But we can be seen. It's one of those things, sometimes you get a mindset where you only go for the really best apparitions and sometimes the others are actually okay. It's just you have to work a bit harder at them. So keen observers may spot it on an uncluttered low horizon in the south east. You will have to set your alarm for 7AM, but Mercury's in twilight. It's always going to be a sill o'clock time, isn't it?

Ezzy 7 a.m.. I think that's, you know, like if you get up early to go to work, it just means getting up a little bit early.

Paul Yeah.

Ezzy I think so. 7:00 I don't think is too unreasonable to be getting up in the morning.

Paul I've done that. I remember there was two planets in the morning sky. It was it was actually Venus and Jupiter. And I remember setting off early for work and parking up and getting some photographs. This is on slide film in those days. Unfortunately, got a bit carried away and then I realised the time when I got in, so I was 5 minutes late, naughty, slapped wrist why are you late. I tried to explain. They weren't impressed when I eventually got the pictures and showed them the went "Wow. Oh, see now why you were late. That's quite impressive. Well done." So it is well worth. But don't go into work late,. Make sure you get up. Don't get in trouble because I don't want you blaming Paul Money or Ezzy Pearson for that. But it is worth it because I say poor Mercury sometimes, it gets a bit of a bad reputation because it's always only visible in twilight, which is true, but some twilight apparitions are better than others. This is a pretty poor one, but it is visible. So you know, you never know. You might spot this over in the south east. It's the left of the south-east low down at 7:00am. And if you do, it'll be the brightest object in that part of the sky anyway. So you know, Well worth having a look at that now on 18th, and we're still in the morning sky at the moment. The Moon has been in the morning sky and it is decreasing in phases, it's heading towards a thick crescent and thinner and thinner and thinner over the next few days. And so on the 18th is actually just above the Orange Star and Antares in Scorpius. This is the heart of the scorpion. So it's going to be a slim crescent. You'll see Earthshine – We've often mentioned Earthshine last year. I'll make no apologies. Going to mention it again because it is gorgeous, this ephemeral glowing of the night side because of light bouncing off the Earth's reflective ocean and atmosphere and sort of light is like fill in flash photographers use, sort of thing. So you've got the bright crescent, which is sunlight, but then you've got the feeble glowing rest of the moon as well. So they always think it looks ghostly. Hanging there in the sky. So on 18th then it's just to the upper right of Antares. And then on 19th it's further down, again look around 7:00, but it's nearly level with Mercury. It's well off to the side. Where is Mercury's sorta to the left of southeast, the Moon is over to the right. But you should see them. So they've got a chance to see Mercury and the Slim Crescent Moon as well, round about the south east to the south southeast for that particular view itself. So, you know, I love these. They're sort of like they are ephemeral events sort of thing. And I think there's some there's an aspect, you know Ezzy about the early morning, but often it's calm still and you don't get that for some reason quite in the evenings, I think. It's probably the bustle of activity. People are probably coming home from work or whatever, but the mornings seems to be calm still and a special time.

Ezzy There tends to still be people on the roads in the evening, even until quite late. People coming home from the pub or from work later in the night. But in the mornings it does it, it is a very different vibe that's happening. I also think this one is quite good. You know, if you've perhaps never looked towards Mercury before, you're never entirely sure whether it is that you've got it this is another good one because it will be level with the Moon. So you've got a nice pointer showing that you're looking in the right area of the sky, which is always a great thing. If you are a beginner, if you're just getting started in astronomy and trying to find out how to find these things, that's a great way to do it. Wait until it's next to something and you'll be able to. If you can find the moon, then you can find it quite easily.

Paul And that's the key isn't it? Because the thing is, the planets do look like stars. I mean, planet means wandering stars. So unless you're familiar with the night sky, then it is easy to actually get mixed up with the stars themselves. But having the Moon away off to the right level, this is the key is actually level with Mercury. So you should know. So look to the left of the Moon. If you see a star on its own, it'll be Mercury instead the innermost planet. Okay, then we do have an unusual... Observationally, there's nothing special in a sense, about this next event. However, it comes around about but once every 12 years. And this is Jupiter at perihelion. Now, perihelion is the closest point of Jupiter's orbit to the Sun. And because Jupiter's orbit is12 years long or thereabouts, it only happens once every 12 years. So if we know is well placed to observe. So I have it in the early evening on the charts I produce sort of thing. And so have a look at Jupiter. It's at its closest to the sun itself. And so it's to say, well, worth having a look at. I mean, let's face it, put a telescope on Jupiter is always a rewarding object, you know, to look at. You've got the belt sort of thing you've got and it's got like.... These sort of like.... The can't think of the... Loops. But uh... plumes! That's what I was thinking of the term. Plumes coming off, especially from the north belt itself. And of course you've got the moons. I think that's why a looms was going on. And it was the moon's brain was getting confused. It's the moons! Now in the evening, as it happens, that we've got three moons off to the right hand side of Jupiter. But Ganymede is transiting. So there's a chance you might see the shadow of Ganymede as well. But that's early evening talk about 5:30. So as on 20th January, Jupiter perihelion, but always worth looking at a telescope anyway.

Ezzy Yeah, because you did mention it will be at perihelion it will be closer to the Sun. I don't think that will actually have any effect on how it appears to us on Earth. It's not going to look look any brighter than it would any other time of year. But it's always a good excuse to look at Jupiter, because people always talk about seeing Saturn, rings of Saturn for the first time or the belts of Jupiter. But for me, it was seeing the moons of Jupiter for the first time. That was when I was like, Oh, that's cool.

Paul I mean, seeing these little tiny dots of light and then the next night they've changed. You think "what". And you realise they're orbiting the planet. And when it is it's one of the... I think it's often almost one of those revolutionary moments when you realise that Jupiter's got like a miniature Solar System with these moons going round it. So I think we're very lucky. We've got a bright planet with four bright moons going round it. Well, to finish this week off, we're on 21st to 22nd. We're back into the evening twilight. Ahh! Something convenient! Even if it probably is very cold. But we have Venus, in conjunction with Saturn, is closest on the 22nd now very close. Well worth having a look at. Photographers, get your cameras out. There is a faint star in line up on the 22nd with them. I'm looking at around about 05:30 in the evening - I say, this is local UK time. And if you look from Saturn down to Venus and carry on, you'll end up in actual fact at one of the brightest stars of Capricornus. Naturally, I haven't brought it up on my chart so I can't tell you, but I think it's either Delta or Gamma. I suspect Delta. But it'll be interesting to see that because you've got two bright planets and it'll be bright Twilight but see if you can see that star as well forming a line. Again, like we said, with the moon, when you've got something obvious to point towards it, you can often see a fainter object easier than you would expect. So but that is the conjunction. So Venus is catching up. It will overtake, as we'll see next week. But I don't want to let you into what's happening next week. So but this is a great conjunction.

Ezzy And if you are seeing Saturn and Venus in conjunction together, how can you tell which one is which? Which one's going to be brighter?

Paul Well, Venus will outshine Saturn tremendously. I can't remember how much percentage, but it is a phenomenal difference. But they'll be quite beautiful in binoculars and a small wide field... one of the Richfield telescopes may well actually just have them in the same field of view. So that I think would be well worth photography wise.

Ezzy You should be able to get them in the same field of view through binoculars then?

Paul Oh, definitely. Yeah. And probably that star as well I mentioned.

Ezzy Definitely one to to grab a pair of binoculars and get out and see that one. So thank you, Paul. Certainly sounds like we've got a packed week this week, actually. On 16th of January, Mercury is going to be creeping into the morning sky. Then on 18th, the crescent moon is going to be next to Antares in Scorpio, great chance to see some earth showing there. On 19th, Mercury in the Moon will seem about level in the sky, so it's a great time to try and catch both of those together. Then on 20th, Jupiter is going to be at its closest approach to the sun, something that only happens every 12 years. So that's always a great excuse to go and look at the biggest planets of our solar system. And then finally, on 21 to 22 January, Venus is going to be in conjunction with Saturn. So it's a great opportunity to grab a pair of binoculars and be able to see those in the field, same field of view. So some great things to look forward to. Thank you very much, Paul, for taking your time to talk us through all of those.

Paul My pleasure.

Ezzy And be sure to join us next week like and subscribe the podcast to make sure that you're always kept up to date with what's going on in the night sky every week. And we'll see you then.

Ezzy 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 where we have a 16 page pull-out 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 the 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 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.