How to see the Leonid meteor shower 2021
The Leonid meteor shower peaks next week, but a nearly-full Moon could make observing them rather tricky.
The Leonid meteor shower 2021 reaches peak activity on 17 November, with the best time to see the Leonids on that date being between midnight and dawn.
However, a bright nearly-full Moon on 17 November will make spotting Leonids in 2021 tricky. In fact, 2 days later, the full Moon will actually be partially eclipsed, as seen from the UK.
For more on this, read our guide on how to see the 19 November lunar eclipse.
Leonid meteors can typically be seen between 10–20 November. They are fast meteors, associated with the debris stream of comet 55P/Tempel-Tuttle.
The radiant - the point in the sky from which the meteors appear to emanate - is in the curved portion of the Sickle asterism in the Leo constellation, the pattern that is meant to represent the Lion’s head.
- For more on seeing shooting stars, read our meteor shower guide.
How to see a Leonid meteor
Leonid meteors are best observed after midnight and technically they should be putting on their best show during the morning of 17 November from 00:00 UT until the onset of dawn, around 05:40 UT.
In 2021, a bright, nearly-full Moon will prevent observers from seeing the sort of show we got from the Leonids in 2020.
But even when the Moon isn't playing ball, meteor showers make for a great excuse to get out and get looking up at the night sky. For more on this, read our guide on what to see in the night sky in autumn.
To see a Leonid meteor, find a place away from the light pollution of towns and cities (providing it is safe to do so) and locate the radiant in the night sky (use a star chart or smartphone astronomy app if need be).
You don't need a telescope or binoculars to see a meteor shower: in fact these would narrow your field of view. Naked-eye observing is best, but give your eyes about 30 minutes or so to properly dark-adapt and you will be able to see more.
This means no looking at your phone or using a torch, as doing so will ruin your dark adapted vision. If you really need to do either, make sure your phone is set to red light mode (if you're an iPhone user, find out how to turn your iPhone screen red) or use a red light torch.
If possible, bring a reclining chair to prevent neck ache from spending long periods of time looking up, and wrap up warm. It is winter after all, and meteor observing involves a lot of standing still in open spaces.
How many meteors will I be able to see?
Zenithal Hourly Rate (ZHR) is a useful term to get to know when you're preparing to observe a meteor shower. It's a term used to describe meteor shower rates, but is really only for comparison and isn't intended to represent actual visual rates.
At its peak the 2021 Leonid meteor shower will have a ZHR estimated in the range of 10–20 meteors per hour.
However, ZHR assumes a shower’s radiant is directly overhead and the observer is able to take advantage of a clear, dark sky with no visual obstructions.
The actual number of meteors that can be seen should be lower than the quoted ZHR, and in 2021 that full Moon will make things even trickier.
Iain Todd is BBC Sky at Night Magazine's Staff Writer. He fell in love with the night sky when he caught his first glimpse of Orion, aged 10.