What's in the night sky in the week of 20 to 26 March, 2023 in our weekly stargazing guide: Ceres brushes past galaxy M100 and goes through opposition this week, while the New Moon offers an opportunity for deep-sky observing.


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 to our 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 hemispheres night sky as we are based here in the UK. All times are in GMT as a particular word of caution to any of US listeners do be aware that your clocks have changed, but others haven't yet, so you might need to take that into account when you are converting. Any times in this episode, we'll be covering the coming week from 20 to 26 March. I'm Ezzy Pearson, the magazine's features editor and unfortunately neither of my co-presenters could join me this week again. But I'm here to run you through all the best things to see in the night sky this week. And after a few quiet weeks, I am very happy to say that this week there are several things to watch out for in the night sky. So let's have a look at what's coming up throughout the nights this week.

Starting on 20 March, it's going to be the equinox. This, in practical terms, is the day of the year where the day and the night is the same length. So 12 hour day and a 12 hour night. And it's caused because the Sun is going to be passing over what's known as the celestial equator. So where it's directly overhead passes over the equator, and that's going to be happening exactly at 21:25p.m. on 20 March. It marks us moving forward into spring. And unfortunately for us astronomers, it does mean we are also moving into the period where the days are going to be longer than the nights, cutting down on our time for astronomy, which is very sad, but that doesn't mean we shouldn't mark these celestial events all the same. Then on 21 March, it's time for the New Moon. So time to get any deep-sky observing that's been on your list done. The Moon's going to be out of the way. You won't have light pollution contributing to any of your images, so hopefully that'll be a great opportunity to get those.

Also on 21 March, it's a great time to see the dwarf planet Ceres. It's going to be passing through the constellation of Coma Berenices and just north of the Virgo cluster, the dwarf planet is about magnitude 6.6, plus 6.6 at the moment. So that does mean you're going to be want to using a pair of binoculars or a small telescope to be able to see it. But it is brighter than most things in the asteroid belt tend to be. So it's a good time to be observing it. And the reason why it's so bright at the moment is because it's heading towards opposition on 23 March. So 21 March is when it's going to be near the Virgo cluster, 23 March, it will be opposition. So that means it'll be opposite the Sun on the sky. So Sun, Earth and then Ceres all in a line. You'll also notice that throughout that section I very carefully refer to Ceres as a dwarf planet, even though it's in the asteroid belt. If you want to find out more about the history of Ceres and its name, do be sure to go back to last week's episode where we go into that in a bit more detail.

Then on 22 March in the evening sky, the moon is going to begin brightening up again. After the New Moon. It's still only going to be 1% lit, so it's going to be a very thin crescent, but about 1.8 degrees away is going to be the planet Jupiter. The moon is about half a degree across, so it's going to be about three to four moon diameters away and Jupiter is going to is very bright at the moment, so you shouldn't have much trouble finding it. It's magnitude -1.9. Any minus magnitude is immediately one of the brightest things in the night sky. So minus two means it's incredibly bright. Unfortunately, the moon is very low on the western horizon at the moment, which means it's quite difficult to see. And it will also be setting very quickly. Jupiter sets about 8:30PM and the moon follows along about 10 minutes later. So you do need to be on your toes to be able to catch these two together. However, with the crescent moon and Jupiter close to the horizon, that also offers a lot of potential photo opportunities. So if you have any interesting foregrounds that you think might offset these two together, then put 22 March in your diary.

There's another double show between the Moon and a planet on 24 March, this time in the morning sky, when the 9% waxing crescent is going to be 57 arc minutes south of the planet Venus, so about a degree south of Venus. But that's going to be happening at 10:10AM so in the morning sky. And by that time the sun will be up. So if you are looking for these to do, be very careful. Never look directly at the Sun, even with your naked eyes, and especially not through optics. In fact, I would leave any kind of telescope or binoculars well alone for observing these too. But if you are out and about and you happen to see the Moon up in the sky next to a bright dot, when you're getting your coffee at 10AM in the morning, that be what that is. So do keep an eye out for those.

Going forward into the evening, though, of 24 March. Moving forward into the evening, the Moon is going to be about two degrees away from the planet Uranus. When the pair set at around 10:25PM, unlike Jupiter and Venus, Uranus is a very dim planet. It's magnitude +5.8. So you really need binoculars or a telescope to be able to see that. However, it does mean that you have the nice Moon that pointing either way to helping towards helping you find Uranus on the night sky. If you are looking for it and if you need a bit of guidance.

Then on the 25 March, the 20% lit crescent Moon is going to be approaching the north west horizon, and it will also be approaching the Pleiades open star cluster, which is a beautiful cluster surround by this charming blue nebulosity, this white blue nebulosity that you can even see that with the naked eye. To really appreciate it, though, you are going to be wanting to look through binoculars or a telescope. But again, they are quite easy to find. And at this time the Moon is going to be about 2.5 degrees away on the night sky, so relatively close together. And it's going to be a great photo opportunity to capture two beautiful things together on the night sky.

Then finally, on 26 March, Ceres is back again, and this time it's going to be passing across the magnitude +9.3 galaxy M100. And it'll be doing that throughout the night and into the morning. So lots of opportunities to be able to see that the two will actually be quite close together for... throughout the week from about 23 to 29 March. You can get them in the same field of view, but on the night of 26th, they are really going to be brushing past each other. Ceres is going to get right up close to the spiral arm of M100. So if you want to see that, do be sure to get out there on 26 March. Thankfully, the moon's going to be cooperating and getting out of the way nice and early, so give you lots of opportunity to be able to see this dark sky object and really appreciate it. To find it, M100 is located next to the bright star diadem in the constellation of Coma Berenice, so you can get a dwarf planet within our own galaxy, next to a galaxy that is 55 million light years away. And I always think when you manage to get those just juxtapositions, it's always a really enchanting thing. A nice reminder about our place in the universe and the size of everything the cosmos around us.

And finally, a reminder to all our UK listeners on 26 March is the date where all of the clocks change. So we will be heading forward into British Summer Time from now on. From next month's episode onwards, all our times will be in British Summer Time. So if you want to make sure that you catch those episodes, do subscribe to the podcast and we will hopefully see you then.

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 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. For more of our podcasts, visit our website at skyatnightmagazine.com or head to 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.