Photographing the Night Sky with a Phone or a Camera

Night-sky photography rests on one idea: stars are faint, so the camera has to collect light for a long time. Everything else follows from that. The camera must stay perfectly still, it must be focused by hand because autofocus fails in the dark, and you have to balance exposure length against the slow drift of the stars.

What you need

• Something to hold the camera still. A tripod is best. NASA’s meteor photography advice adds that a light tripod can be weighed down, for example with a sandbag, so wind doesn’t shake it. For a phone, a small tripod with a phone clamp works, and so does a rock or a block of wood.
• A way to fire the shutter without touching it. A remote release, or the built-in self-timer.
• A dark site. Light pollution brightens the background and swamps faint stars and meteors. NASA puts getting away from city lights near the top of its list.
• Spare batteries. Long exposures and cold nights drain them quickly.
• A dim red light, so you can see your controls without losing your night vision.

With a phone

Phones have improved a lot. Most recent models have a night mode that takes a long exposure, or a burst of shorter ones, and merges them into one cleaner picture. On iPhones it is called Night mode. On Google Pixel phones it is Night Sight. Google’s engineers wrote that Night Sight on the Pixel 4 can gather light for up to four minutes in total. It splits that time into frames of no more than 16 seconds, because longer single frames turn stars into short streaks.

The NASA Night Sky Network’s smartphone guide gives this sequence:

1. Steady the phone on a small tripod, or prop it on a rock or a block of wood. In low light this matters even more than usual.
2. Set the timer so tapping the shutter button doesn’t shake the phone.
3. Focus on a bright star or a distant streetlight by tapping it, then lock the focus so the phone doesn’t hunt for it again.
4. Lengthen the exposure to several seconds, or as long as night mode allows. If your phone’s camera app has no manual control, a third-party camera app can add one.
5. Process the photos afterward in an app or on a computer. The guide calls post-processing the secret of all astrophotography.

Turn off the flash, since it only lights up the nearest few feet. Wipe the lens, too; a smudge from a pocket turns every bright star into a smeared glow.

What a phone does well

Phones are good at wide scenes: constellations over a landscape, a bright planet beside the Moon, the glow of the northern lights, and the Milky Way from a truly dark site. They can catch a bright meteor if you leave them taking shot after shot. They struggle with fine detail on faint objects, because their lenses and sensors are tiny. For the Moon or a planet, NASA suggests holding the phone up to a telescope eyepiece, ideally with an adapter that clamps it in place.

With a camera

A camera with manual controls, an interchangeable lens and a sensor much larger than a phone’s gives cleaner, sharper results. Any camera that lets you set the exposure time, aperture and ISO yourself will work.

Lens

Use the widest lens you have. NASA explains that a wide-angle lens covers more of the sky, so it catches more meteors, while a telephoto lens covers too little sky to be useful. The Planetary Society recommends a wide-angle lens with a wide maximum aperture, f/2.8 or lower if possible, because a low f-number lets in more light.

Focus

Switch the lens to manual focus. Autofocus can’t lock onto stars. Point at a bright star or a far-off light, zoom in on the camera’s live view screen, and turn the focus ring slowly until the star is as small and sharp as possible. NASA recommends taking test frames and checking them until the stars are points rather than blobs. The National Park Service tip sheet suggests a strip of masking tape to keep the focus ring from moving once it’s set.

Exposure: the 500 rule

Because Earth turns, stars drift across a fixed camera’s view. Expose too long and they become short lines. NASA gives a simple rule of thumb: divide 500 by the focal length of your lens in millimeters, and the result is about the longest exposure in seconds before trails appear. With a 20 mm lens that is 500 ÷ 20, or about 25 seconds. With a 50 mm lens it is about 10 seconds. The Planetary Society adds that on a crop-sensor camera you multiply the focal length by 1.5 first, and that the rule is only a starting point, so zoom in on your first frames to check that the stars are still round.

Starting settings

These ranges come from The Planetary Society, and NASA’s example meteor photos use exposures in the same 10-to-30-second range. They are a place to start, not a fixed recipe:

Setting	Starting range
Exposure	10 to 30 seconds (stay within the 500 rule)
Aperture	f/2 to f/2.8, or your lens’s widest
ISO	1,600 to 6,400
White balance	about 4,000 to 5,000 K (daylight or auto)
Focus	manual, on a star
File type	RAW if available (NPS tip)

If the picture is too dark, NASA suggests raising the ISO or opening the aperture. If it is grainy, lower the ISO and lengthen the exposure, as long as the stars stay sharp.

Photographing meteors

Meteors are a waiting game. You can’t predict where the next one will appear, so the trick is to keep the camera shooting:

1. Set up on the peak night of a shower, in the darkest place you can reach. Our meteor shower calendar shows each peak and how bright the Moon will be.
2. Aim the widest lens you have at a dark part of the sky, with some of the radiant region in the frame but not centered on it. Meteors farther from the radiant leave longer trails.
3. Set the exposure, focus and ISO as above, then use the camera’s interval timer (or a remote with a lock) to take one exposure after another for an hour or more.
4. Check the frames later. Most will show only stars. A few will catch a meteor.

On a phone, an app that shoots continuous long exposures does the same job. Our guide to watching a meteor shower explains when and where to look.

Not every streak is a meteor. Planes leave dotted lines from their blinking lights, and satellites leave steady lines that often continue into the next frame.

Photographing the stars and the Milky Way

For stars over a landscape, frame a tree, rock or building against the sky, and use the same settings. Moonless nights work best for the Milky Way, which is faint and washes out completely in moonlight or city glow. Our guide to the best time to stargaze covers moon phase and darkness.

A final check before you leave

• Tripod, phone clamp or camera, remote or timer.
• Charged and spare batteries.
• Lens set to manual focus, focused on a star.
• Flash off, screen dimmed, red light on.
• A clear forecast and, ideally, no Moon.