How to photograph a meteor shower

Why aperture matters more than exposure time

A meteor is a moving point of light. Its image sweeps across the sensor, so each pixel along the trail receives light for only a split second. Leaving the shutter open longer does not make the trail any brighter; it only lets more background skyglow build up behind it. The one setting that makes a meteor brighter in your frame is a wider aperture.

That shapes everything else in this guide. A fast lens is worth more than an expensive body, and an f/1.8 lens gathers about 2.4 times the light of an f/2.8 lens, roughly one magnitude. Because faint meteors far outnumber bright ones, that one magnitude adds a large share of extra meteors to your frames.

Gear

• Lens. Wide and fast: about 14 to 24 mm on a full-frame camera (roughly 10 to 16 mm on APS-C), at f/2.8 or faster. Wide, because meteors land anywhere across tens of degrees of sky; a tight frame mostly records empty sky.
• Camera. Any body with manual exposure and RAW files will do. Better high-ISO performance helps, but a fast lens helps more.
• Tripod. A sturdy one. Any bump during the night ruins the alignment of a stack.
• Intervalometer. Built into many cameras; otherwise an inexpensive wired remote. It fires frame after frame without you touching the camera.
• Power. Cold drains batteries fast. One EarthSky writer found a lithium-ion battery lasted about an hour and a half of near-continuous shooting on a cold night. Bring several, and keep spares warm in an inside pocket.
• Storage. At 20-second exposures with 1-second gaps, the camera shoots about 170 frames an hour, or roughly 1,000 over a six-hour session. Raw files at that rate add up to tens of gigabytes.
• Dew heater. A USB heater strip around the lens barrel, or a chemical hand warmer strapped to it, keeps dew and frost off the front glass through the small hours.

A phone on a small tripod, in its night or long-exposure mode, can catch the occasional bright meteor. Treat it as a second angle or a bonus, not as your main camera.

Settings: a starting recipe

For a dark site with no moon:

Setting	Starting value	Why
Mode	Manual	Nothing should change between frames
Aperture	Wide open, or one-third stop down if the corners are poor	Aperture is what records faint meteors
Exposure	15–25 seconds	Short enough to keep stars nearly round
ISO	1600–3200 (800–1600 under skyglow or moonlight)	Background should sit left of center on the histogram, not crushed against the edge
File format	RAW	Room to fix color and exposure later
White balance	Fixed, around 4000 K	Auto white balance can shift from frame to frame and make stacking harder
Long-exposure noise reduction	Off	It takes a second exposure as long as the first, during which the camera can’t shoot
Drive	Intervalometer, about 1 second between frames, unlimited frames	The gap between frames is where meteors are lost

The 500 rule gives a quick exposure limit before stars visibly trail: 500 divided by the focal length, or about 25 seconds at 20 mm. On high-resolution sensors, trailing shows sooner; the stricter NPF rule, which accounts for pixel size and aperture, often gives roughly half the 500-rule time. For meteor work, slight trailing at the edges is a fair trade for fewer gaps, so don’t shorten exposures so much that the camera spends a large share of its time between frames.

Some intervalometers measure the interval from the start of one frame to the start of the next. On those, set it one second longer than the exposure. Turn off image review after each shot and dim the rear screen; each bright preview costs your own night vision.

Focusing in the dark

Autofocus can’t lock onto stars, and the infinity mark on many lenses is only approximate. Switch the lens to manual focus, point at the brightest star or planet you can find, and magnify the live view as far as it goes. Turn the focus ring slowly until the star is the smallest, tightest point you can get, then tape the ring in place.

Check again after an hour or so. Lenses can shift focus as they cool through the night, and a soft frame at 3 a.m. is a common way to lose the best hours.

Where to aim

Meteors trace back to the radiant, but near it their trails are foreshortened into short dashes, because they are coming nearly toward you. Trails grow longer with distance from the radiant, and the ALPO notes that their apparent speed peaks about 90 degrees away. So use the radiant as a reference, not a target. Put it near one edge of the frame or just outside it, so the long trails cross the middle of the picture.

Aim reasonably high, around 40 to 60 degrees above the horizon, where the sky is darker and the haze thinner, unless you want a foreground in the frame. A treeline, ridge, barn or still lake turns a frame with a meteor in it into a photograph. If the Milky Way is up, it can share the frame with the radiant’s side of the sky.

If you have a second camera, point it at a different part of the sky. Two frames cover far more sky than one, and they don’t need to match.

Keep the moon out of the frame and behind you if you can, and use a lens hood. Moonlight can hide more than half the meteors you would otherwise catch, so the hours after moonset or before moonrise are the ones to protect.

During the night

Take a test frame, check focus and the histogram, and then leave the camera alone. Every adjustment costs frames and breaks the sequence. Go and watch with your own eyes; how to watch a meteor shower covers the rest of the night. Once an hour, use a dim red light to check the battery, the lens for dew and the focus.

Most frames will be empty, and that’s normal. The camera only records the brighter meteors, and its frame covers less sky than your eyes do.

Not every streak is a meteor. When you sort the frames later, use these differences:

• Airplanes leave dotted or dashed trails from their blinking lights, often in more than one color, and usually cross several frames in a row.
• Satellites leave smooth streaks of even width that fade in or out gradually, and often continue into the next frame.
• Meteors appear in a single frame, usually taper or flare along their length, often show color, and point back toward the radiant if they belong to the shower.

Building an honest composite

The images with dozens of meteors streaming from one point are composites, and there is an honest way to make one. Keep the tripod fixed all night. Pick one frame as the base, usually the one with the best sky or foreground. Then align every meteor-bearing frame to it on the stars, since the sky turns 15 degrees an hour, and layer just the meteors onto the base. Night-sky stacking tools such as Sequator (Windows) or Starry Landscape Stacker (Mac) can register the frames on the stars, and an image editor with layers and masks handles the rest.

Because each meteor is placed where it actually appeared against the stars, the radiant shows up in the composite on its own, and the picture is a compressed record of the night, not a collage. Say that it is a composite and give the time span it covers. The image is no less true for saying what it is.

If you’d rather not composite, a single frame with one bright meteor over a good foreground is the classic meteor photograph. A fast lens, the right night and a long session give you the best odds of getting one.