How do I photograph the night sky?

Astrophotography looks like an equipment problem and is mostly a location and technique problem. A modest camera under genuinely dark skies beats an expensive one in a town.

Safety

What you'll need

• A tripod
• A lens with a wide aperture, ideally f/2.8 or wider
• A head torch with a red mode
• Spare batteries — cold drains them fast

Step by step

1. Get away from light pollution.This matters more than anything else. A light pollution map will show you the nearest genuinely dark area. Even a short drive out of a town makes a visible difference.
2. Check the moon and the weather.A bright moon washes out the stars as effectively as a streetlight. Aim for a new moon, clear skies and low humidity. The Milky Way is best placed in the UK from spring through autumn.
3. Arrive in daylight if you can.Find your composition, note the foreground and the hazards, and set the tripod up before it is dark. Scouting in the dark is slow and unsafe.
4. Put the camera on a tripod.Non-negotiable — exposures are measured in seconds. Weigh the tripod down with a bag and turn off image stabilisation, which can cause blur when the camera is on a solid support.
5. Focus manually on a bright star.Autofocus will not work. Switch to manual, use magnified live view on the brightest star, and turn the focus ring until it is the smallest point possible. Then tape the ring so it cannot move.
6. Open the aperture fully.f/2.8 or wider if you have it. This is the one situation where the maximum aperture of a lens really does determine what is possible.
7. Apply the 500 rule for the shutter.Divide 500 by the full-frame equivalent focal length to get roughly the longest exposure before the stars trail — about 20 seconds at 24mm. Longer and the stars become short lines.
8. Set ISO around 1600 to 6400.Start at 3200 and adjust. Astrophotography needs far higher ISO than feels comfortable, and noise reduction in editing deals with a lot of it.
9. Shoot raw.The editing latitude is essential — night sky images almost always need substantial adjustment of white balance, contrast and noise.
10. Use the self timer.Two seconds, so the camera has stopped moving after you touch it. Or a remote release.
11. Include a foreground.A tree, a ruin, a ridge line. A photograph of nothing but stars has no sense of scale and rarely holds attention.
12. Try star trails as the alternative.If you cannot get short-enough exposures, do the opposite deliberately — many long exposures stacked, or one very long one, so the stars draw arcs around the pole star.

Tips

• Dark skies beat expensive equipment. Check a light pollution map before anything else.
• Tape the focus ring once you have set it. It is very easy to knock in the dark.
• Take twice the warm clothing you think you need. Standing still is much colder than walking.

Common mistakes

• Trying to autofocus in the dark — There is nothing for the autofocus to lock onto, so it hunts and settles somewhere arbitrary. Manual focus on a magnified bright star is the only reliable method.
• Exposing for too long — The Earth rotates, so beyond roughly 500 divided by the focal length in seconds, stars record as short lines rather than points. Raising ISO is the correct way to gain brightness instead.

If it doesn't work

Questions people ask