Conditions are looking good for this year’s Leonids. Here’s how and when to watch some of the fastest meteors of the year.
The Leonid meteor shower is fast and is well-known for its impressive, bright fireballs. Every so often the Leonids will produce ‘meteor storms’, where viewers can see meteors in their thousands. Sadly, 2023 is not predicted as a meteor storm year, but the shower is still well worth watching, especially if you’re in an area with little-to-no light pollution.
But how can you spot a Leonid? Will you need any equipment? And, where do the Leonids come from in the first place?
If want to plan ahead for upcoming meteor showers in the UK, check out our guide, and if you’re looking for more stargazing tips, be sure to check out our astronomy for beginners guide and our full Moon UK calendar.
When is the Leonid meteor shower 2023?
The Leonid meteor shower peaks on Saturday 18 November 2023, in the early morning just before sunrise. You can still see meteors from the shower on the night of Friday 17 November, and the night of Saturday 18 November.
“The Leonid meteor shower is active between 3 November and 2 December. Peak rates occur mid-November, this year’s maximum predicted for 6am on 18 November,” explains veteran astronomer and BBC Sky at Night presenter, Pete Lawrence.
“Leonids are amongst the swiftest meteors, the particles forming Leonid trails entering our atmosphere at a speed of 70 km/s (44 miles/s).”
What is the best time to see the Leonids?
The best time to see the Leonids will be between midnight and dawn on 18 November 2023.
“The night of 17/18 November should give the best rates but if the weather is poor, the nights before and after should be fine too,” explains Lawrence.
“On the night of 17 November, the waxing crescent Moon sets around 5pm leaving the sky good and dark for a Leonid watch. The radiant doesn’t rise until 10:30pm, so a watch from 11pm until dawn on 18 November is recommended.”
You’ve got the best chance of spotting the most meteors when the radiant is highest in the sky, which gets higher as the dawn approaches. Watching when the radiant is high, means the meteors are entering Earth’s atmosphere from nearly overhead.
This allows you to see meteors streaking across a larger portion of the night sky, making them more visible and frequent. When the radiant is nearer the horizon, part of the view is essentially ‘cut off’, and many meteors may end up out of sight.
Where to look to see the Leonids
The Leonids appear to originate from the constellation Leo the Lion, as Lawrence explains: “The shower is named because its radiant is within Leo the Lion during peak activity.”
But the meteors don’t actually come from the radiant, that’s just how it appears from our vantage point on Earth.
“A shower’s radiant is the area of sky which associated meteor trails appear to emanate from. For the Leonids, it’s within a backward question mark pattern of stars [within the constellation Leo] called the Sickle,” Lawrence says.
The easiest way to find the Sickle is by first locating the Plough, in Ursa Major. This distinctive asterism can be used as a signpost, to help you locate other constellations in the night sky.
Turn your attention towards the lip of the saucepan (away from the handle), and locate the two bright stars, Dubhe and Merek. These are useful ‘pointer stars’, and by extending an imaginary line northward between the two, will point towards Polaris, the North Star, and the Sickle in Leo if you head the opposite direction.
But you don’t need to look solely at the radiant to spot meteors. In fact, often most meteors won’t become visible until they’ve travelled some way away from the radiant. When watching for meteors, try to take in as much of the sky as possible in your field of view, a buffer of around 45 degrees around the radiant should do the trick.
You can look further away still, and this will give you the added bonus of spotting longer meteor trains. It’s all down to perspective and the angle we’re looking at them; like the stars that stretch out either side of the Enterprise when the galaxy-class starship goes to warp (we’re counting the days until 5 April 2063), or that screensaver from the 90’s.
Nearer the radiant, the meteor paths are shorter; a very short flash indicates a meteor that’s coming towards us.
Where do the Leonids come from?
“Leonid meteors are associated with Comet 55P/Temple-Tuttle,” Lawrence says.
Comet 55P/Temple-Tuttle, or Comet Temple-Tuttle for short, is a periodic comet, comprised mainly of ice and dust. Like Halley’s Comet, which gave us the Orionids in October, Comet Temple-Tuttle is in a retrograde orbit around the Sun. This means that it’s travelling in the opposite way to the Earth.
But while Halley’s Comet takes 75-76 years to make one orbit, Comet Temple-Tuttle only takes 33 years to orbit the Sun.
As comet Temple-Tuttle orbits the Sun, it leaves a trail of dusty debris in its wake, which gradually gets spread around the comet’s orbit. When the Earth’s orbit subsequently intersects with this trail of debris, these bits of dust collide with our atmosphere and disintegrate. The result is streaks of light that we see as shooting stars.
How many Leonid meteors will we be able to see?
At the peak of the Leonid meteor shower, we can realistically expect to see around 10-15 meteors per hour, perhaps less.
“Earth’s passage through this comet’s orbital debris typically brings a peak zenithal hourly rate (ZHR) of 15-20 meteors per hour,” Lawrence says.
But there’s a catch. “The ZHR figure assumes perfect viewing conditions with the radiant overhead. As these conditions are rarely ever met, expect the true visual hourly rate to be significantly lower.”
Occasionally, however, the Leonids produce what’s known as ‘meteor storms’. In 1966, witnesses experienced thousands of meteors per minute during a 15-minute period, it was a spectacular event – and one of the best meteor storms in living memory.
Further back, the 1833 meteor storm was said to be “raining fire”, and produced up to 150,000 meteors per hour!
These meteor storms seem to occur in cycles, but the next one is not predicted for another decade:
“The Leonid shower is famous because of outburst events occurring at roughly 33-year intervals. During such periods peak rates may increase significantly, sometimes producing thousands of meteors per hour. The next predicted outbursts are for 2033 and 2034 when ZHRs of 400 and 500 respectively, are predicted,” explains Lawrence.
Viewing tips: How to maximise your chances of spotting a fireball
You don’t need any equipment to watch a meteor shower, although a tally counter can be useful to keep track of the meteors you see.
“If the sky is clear on peak night, a reclining garden chair makes a perfect viewing platform. Adjust it so you’re looking two-thirds up the sky. Any direction works, but the view south is recommended. Allow at least 20 minutes in total darkness before starting a watch, giving time for your eyes to properly adjust to the dark,” advises Lawrence.
Try not to look at other bright sources of light during this time, including your phone. But as the rod cells in our eyes are not sensitive to red light, if you do need to check something it’s advisable to use a red filter or red-light torch.
About our expert
Pete Lawrence is an experienced astronomer and astrophotographer, and a presenter on BBC’s The Sky at Night. He previously graduated from the University of Leicester with an honours degree in physics with astrophysics.
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