With a relatively short period of activity of just over a week, tonight's Ursid meteor shower is underway in the northern hemisphere. Following the winter solstice yesterday, the Ursids peak tonight, 22-23 December 2023, when the meteor shower is expected to produce around 5-10 meteors per hour. However, with an almost full Moon to contend with, patience is key.
If you’re looking for other targets to spot while you wait for that elusive Ursid, check out our Astronomy for Beginner’s guide for some easy constellations to get you started.
When is the Ursid meteor shower in 2023?
The Ursid meteor shower is peaking tonight, in the early morning hours of 22–23 December 2023. The meteor shower is active between 17 and 26 December 2023 (but you won't see as many meteors outside the peak window)
It’s a relatively minor shower so we can only expect to see up to 10 meteors per hour – and there’s also an interfering almost-full Moon. This is in stark contrast to the Geminids earlier in the month where we could see up to 150 meteors per hour.
"Just as the Geminids, the best shooting-star shower of the year, fades away on 17 December, the Ursids meteor shower takes over," explains Dr Darren Baskill, an astrophysicist from the University of Sussex. "The crisp, cold nights at this time of year are great for observing the night sky - as long as you wrap up warm! "
What is the best time to see the Ursids?
The best time to spot shooting stars from the Ursid meteor shower is between around midnight and 5am on 23 December 2023.
At this time, the radiant will be positioned at its highest point in the sky, so meteors streaking away from it cover a shorter distance in the atmosphere, resulting in longer and more visible trails.
The sky is also generally darker at this time and, as we approach 5am, the Moon will have set (in both the US and UK). And due to the rotation of the Earth, we’ll be turning into the direction of Earth’s orbital motion. This means we’ll be facing the oncoming meteors at this time, increasing the chances of meteoroids entering Earth’s atmosphere and burning up – and therefore we have more chance of seeing meteors.
Where to look to see the Ursids
The Ursids will be visible across the whole sky, but they will appear to radiate from a single point, directly overhead. This point is called the ‘radiant’ and is located in the constellation of The Little Bear, Ursa Minor (also called the Little Dipper).
Ursa Minor is always above the horizon and is a constant feature of northern skies. It’s also home to the north celestial pole, marked by the pole star, Polaris.
Ursa Minor never rises or sets, and is surely the dizziest of all the constellations, spinning around the pole once every 24 hours. It’s a relatively small constellation, with Polaris marking the end of the Little Dipper's handle.
Find the radiant of the Ursid meteor shower by following these five easy steps:
- Locate the Big Dipper, Ursa Major: The Big Dipper (aka the Plough) is a prominent asterism and part of the Ursa Major constellation. Look for its distinctive shape, which resembles a large ladle or saucepan.
- Identify the Pointer Stars: In the Big Dipper, find the two stars that form the outer edge of the ladle's bowl. These are called the Pointer Stars; Dubhe and Merek.
- Extend a Line from the Pointer Stars: Imagine a line extending from the two Pointer Stars, and follow it in the direction away from the ladle.
- Find Polaris (North Star): Continue along the imaginary line, and you'll come to Polaris, the North Star. Polaris is the brightest star in the Ursa Minor constellation and is very close to the north celestial pole.
- Follow the handle: From the pole star, follow the handle of the Little Dipper and you’ll reach a similar ladle as in the Big Dipper. The radiant is just above this point.
Although knowing where the radiant is located is useful, especially when it comes to distinguishing your Ursids from your Geminids, the Ursids will be visible across the whole sky. If possible, it’s best to find a location where you can scan as much of the night sky as possible.
How to maximise your chances of spotting an Ursid
You don’t need any special or expensive equipment to view meteor showers; your eyes are the best instrument.
Here are some top tips on how to maximise your chances of spotting one of the rare and elusive Ursids:
- Maximise darkness: If you can, find a location away from streetlights and other sources of light pollution.
- Let your eyes adjust: You’ll be able to notice more if you let your eyes adjust to the dark. Sit outside for around 10-20 minutes, and resist the temptation to look at your phone (or other bright lights) at this time. You’ll become accustomed to the darkness and your eyes will be able to pick out stars and meteor trails with more ease.
- Protect against the elements: It’s cold, so grab a blanket and a thermos. Might as well make an occasion of it.
- Get comfy: If you have a reclining chair, or hammock not obscured by overhead branches, this is the ideal way to take in as much of the sky in your field of vision.
- Use a red light: If you absolutely must check your phone, use a red filter – or a red-light torch if you need to pop back into the house for something. Avoid switching on any other lights and ruining your accumulated night vision. (Red light works because the rod cells in our eyes are not sensitive to this part of the light spectrum, so it doesn’t interrupt the accumulated night vision.
Where do the Ursid meteors come from?
The Ursid meteor shower is associated with Comet 8P/Tuttle, a contact-binary comet.
Contact binary comets are made up of two distinct, separate objects (typically icy bodies or chunks) that are in physical contact with each other. They are thought to form from collisions, mutual capture or rotational fission. Comet 8P/Tuttle is comprised of “two roughly spherical lobes measuring 3 and 4 km in diameter”.
As Comet 8P/Tuttle orbits the Sun, it leaves behind dust and debris. When Earth’s orbit intersects with this debris – which it does every year in December – the small particles and dust from the comet burn up in the atmosphere. From our viewpoint here on Earth, the result is bright streaks in the sky that we see as shooting stars.
It’s a periodic comet (that means it has an orbit of less than 200 years), with an orbital period of 13.6 years, following a regular and predictable orbit around the Sun.
Like the elusive 46P/Wirtanen that teased us with a brand new meteor shower earlier this month, 8P/Tuttle is influenced by the gravitational pull of Jupiter.
How many Ursid meteors will we be able to see?
Under perfect conditions, we could expect to see between 5 and 10 meteors per hour.
However, as 2023 comes to a close, we have an almost full Moon to contend with, so conditions are not favourable and it’s likely we won’t see this many.
How can you tell Ursid meteors from Geminid meteors?
You might think that shooting stars are all the same – they’re not! Most of the time they come from different sources and it’s satisfying to know which comet is producing which shower. They also travel at different speeds.
The Ursid meteor shower is active just as the Geminids come to an end, and there is also the chance of spotting the odd sporadic here and there. So how can you tell which is which?
This is where the radiant comes in; different showers appear to originate from different parts of the sky. For the Ursids, that location is directly overhead, but for the Geminids that location is in the constellation Gemini.
Then there’s speed: the Ursids are typically slower-moving and have a shorter tail, whereas the Geminids are often bright, colourful and can be fast.
About our expert, Dr Darren Baskill:
Dr Darren Baskill is an outreach officer and lecturer in the department of physics and astronomy at the University of Sussex. He previously lectured at the Royal Observatory Greenwich, where he also initiated the annual Astronomy Photographer of the Year competition.
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