The Geminid meteor shower takes place every December with peak activity occurring halfway through the month. During the Geminids’ peak, observers can expect a zenithal hourly rate of up to 120.
This is the total number of meteors you might expect to see during the peak under absolutely perfect conditions, and so the real number will be somewhat lower.
Expect to see between 35-55 meteors per hour if you are under a dark sky and 14-22 if you are somewhere with less perfect skies.
What is a meteor shower?
Meteor showers usually occur when Earth passes through the trail of debris left by a comet.
The Geminids are unusual, however, in that the trail of debris was left behind by an asteroid, 3200 Phaethon.
Where can I see the Geminids?
Meteor showers are one of the easiest astronomical events to observe as they are best seen with the naked eye making it the perfect opportunity to get both children and adult beginners excited about astronomy.
Find a place that is dark and away from light pollution, such as a location away from towns and cities, provided it is safe to do so.
If you are lucky enough to live under very dark skies and can observe from the comfort of your own garden, turn off the lights in your house so they don’t spoil the view.
Avoid using lights such as torches and mobile phones as this will spoil your dark adapted vision.
If you need to see in the dark, use a red torch. If you need to look at your mobile phone, you may be able to turn your screen red in the settings.
The radiant of the Geminids comes from just beside the bright star Castor. Credit: Pete Lawrence
It will take around 20 minutes for your eyes to dark adapt, but hopefully after a little wait you should start to see meteors shooting across the sky.
Remember: clear nights are cold nights. You will be sitting still for a long time, so wrap up warm, bring something to eat and perhaps a hot drink as well.
How do I find the Geminids?
The area of the sky from which a meteor shower appears to originate is known as the ‘radiant’.
The Geminids are so-called because they seem to radiate out from the constellation of Gemini.
To find Gemini, imagine a line between Orion’s right foot (Rigel) and left shoulder (Betelgeuse), then follow that line on for around the distance between your thumb and little finger stretched out at arm’s length.
There should be a pair of bright stars here: Castor and Pollux, the ‘heads’ of Gemini’s twins.
The radiant is just by Castor, but you want to look slightly away from this region rather than directly at it. If you spot a meteor coming from this region, you’ve seen a Geminid.