Every July and August comes one of the best meteor showers of the year — the Perseids.
These streaks of dust coming through our atmosphere are known to be bright and fast, leaving lingering, colourful trails for skywatchers. The Perseids are also frequent, peaking at 50-100 meteors per hour.
In 2020, the shower will peak the evening of August 12-13 in the Northern Hemisphere; luckily, the Moon will be in its last quarter and not interfering greatly with observations. Here are the basics about seeing the shower, and how to photograph its meteors.
The Perseids occur when the Earth runs into the stream of debris left behind from Comet 109P/Swift-Tuttle. This comet is periodic, meaning that it returns again and again to the inner Solar System. Its last visit was in 1992, and it is expected to return again in 2125.
The radiant — the apparent direction from which the meteors flow — is in the constellation Perseus. To find Perseus, look for the Big Dipper. Locate the two stars at the front of the dipper “pot” and trace your eye “above” the pot, to the north star Polaris. From Polaris, continue the virtual line until you reach the W-shaped Cassiopeia. Just south of Cassiopeia is Perseus.
Note that for best results, you should look a little bit away from the radiant to make sure you see the longest and brightest meteor streaks. Choose a moonless night and if you can, head outside during the pre-dawn hours. Give your eyes 20 minutes to adjust to the darkness. Stay as far away from artificial light as possible, and use red filters to dim any flashlights or smartphones.
You won’t need to use binoculars, telescopes or extreme magnification to take pictures of the Perseids. Your best bet instead is to pick a direction of the sky, mount your camera on a solid surface or on a tripod, and to use a wide-angle lens for an exposure of between 10 and 30 seconds. You will need to take multiple exposures, as you won’t know exactly when the meteors will streak.
Put your lens at the widest aperture possible and set the focus to infinity, focusing on a bright planet or star to make the image sharp. Use ISO 1600 and point your camera straight up, to the darkest direction of the sky. Then it’s only a matter of taking pictures – lots of them. You probably will have hundreds of shots of empty space, but if you’re lucky, at least a couple of exposures will show a Perseid streaking in front of you.
Elizabeth Howell (Ph.D.) is a Canadian space journalist who has been obsessed with the topic ever since she, as a young teenager, saw the movie Apollo 13 in 1996. She grew up wanting to be an astronaut. While that hasn’t happened (yet), Elizabeth has seen five human spaceflight launches — including two from Kazakhstan — and she participated in a simulated Red Planet mission at the Mars Society’s Mars Desert Research Station in Utah.