The Perseid meteor shower is one of the most dramatic things to see in the night sky between July and August.
Find out the best dates to see the spectacular display, as well as where to look and how to photograph it.
What causes the Perseid meteor shower?
The Perseid (Per-see-id) meteor shower is one of the highlights of many meteor hunters’ calendar due to its high hourly rate and bright meteors, caused by the Earth slamming into the debris left behind by comet 109P/Swift-Tuttle in July and August every year.
It is called the Perseids because the meteors seem to originate from the constellation of Perseus. Astronomers call this point the meteor shower’s radiant.
Find out more key meteor shower dates throughout the year here.
How to see the Perseid meteor shower
Observers can look out for the shower wherever they are, but there are certain kinds of places that will increase your chances of spotting meteors.
Plan ahead and check the weather forecast. If it is likely to be inclement, find a different location or go out on a different day. The days leading up to the peak are usually better than the days after.
Reduce the amount of light pollution in your field of view. This could mean heading out to the countryside, a nearby park or even do something as simple as turning your back to street lamps if you are not able to go anywhere. Give your eyes at least 15 minutes to adjust to the dark so that you can catch more of the fainter meteors – this does mean that you should not look at your phone!
Meteors can appear in any part of the sky so the more sky you can see the better. Find an area with a clear view of the horizon and away from trees and buildings. Binoculars and telescopes are not necessary as they will restrict the size of the sky that will be visible to you.
However, there are many astronomical targets to look out for that would look magnificent through a telescope – take a look at our Night Sky highlights to find out more.
When is the Perseid meteor shower in 2021?
In 2021 the Perseid meteor shower is active between 16 July and 23 August, with the number of meteors increasing every night until it reaches a peak in mid-August, after which it will tail off. This year the peak falls on the night of the 12th and before dawn on 13 August.
Date of Maximum
16 July - 23 August
Many bright fast meteors with trains. Associated with Comet Swift-Tuttle (1737, 1862, 1992)
What time is best to see the Perseid meteor shower?
The best time to see anything in the night sky is when the sky is darkest and when the target is at its highest position in the sky. For meteor showers, this usually occurs between midnight and the very early hours of the morning.
12 midnight – 05:30am
The radiant of the Perseids is actually always above the horizon as seen from the UK, which means that observers in the UK should be able to see some meteors as soon as the Sun sets. Therefore, it is worth looking up in the early evening.
It is always favourable to try and spot meteors when the Moon is below the horizon or when it is in its crescent phase, because otherwise it will act as a natural light pollution and will prevent the fainter meteors from being visible.
Why should you look out for the Perseids?
It is simply one of the best meteor showers of the year because it produces bright meteors and is one of the most active. The Geminids also has a high hourly rate; however, they occur in December when the Northern Hemisphere experiences winter. The Perseids take place over the school summer holidays in many parts of the Northern Hemisphere, which allows family groups to witness the shower together.
There is also a high chance of seeing fireballs, which are very bright meteors, as well as meteors with long trains during the Perseid meteor shower.
What is the Perseid meteor shower?
As comets get close to the Sun, they heat up and pieces break off. If the debris ends up in the Earth’s path around the Sun, it can slam into our atmosphere at speeds of between 7 – 45 miles per second. The actual speed that a meteor enters our atmosphere travels at depends on the combined speed of the Earth and the debris itself.
The average speed for a Perseid meteor is 36 miles per second. The air in front of the meteor is squashed and heated to thousands of degrees Celsius. The smaller meteors vaporise and leave behind a bright trail of light. Larger meteors can explode as fireballs.
Giovanni Schiaparelli was the first to realise the connection between meteor showers and comets. Lewis Swift and Horace Tuttle had discovered a new comet (which now bears their names) two years before Schiaparelli announced that the orbit of this comet coincides with the path that the source material for the Perseids take.
Find out the difference between an asteroid, a comet, a meteor, and a meteorite in the video below.
Myths, legends and associations with the Perseid meteor shower
Perseus was a hero who beheaded the Gorgon Medusa and later married Andromeda according to Greek Myths. They had nine children together and the word ‘Perseids’ is derived from the Greek word ‘Perseides’ which refers to Perseus’ descendants.
In some Catholic traditions, the Perseids is also known as ‘the tears of St Lawrence’, due to its peak roughly coinciding with the date which the Saint achieved martyrdom.
- The Perseids is also associated with the god Priapus, who was believed by the Romans to have fertilized the fields by ejaculating on them once a year on the date the shower peaks.
This article has been written by an astronomer at the Royal Observatory, Greenwich. Updated 5/3/21.