How to shoot and edit a star trail photo

1 Point to the poles

If you want to achieve the effect of concentric circles in your star trail, you must point your camera to the north if you are in the northern hemisphere, or to the south if you are in the southern hemisphere. If you know the night sky well, this will not be a problem, but for most photographers, it’s best to use a compass.

2 Compose your image

Before it gets completely dark, suss out your surroundings and compose your shot, being careful not to have any close artificial lights in the composition. This can be tricky! The darker your location, the better. In Manual mode, set your camera to 30 seconds at f/2.8, ISO 800. (Exact settings depend on light pollution and moonlight).

3 Take the same photo over and over

Adjust the ISO and aperture until you’re happy with the image on your camera’s rear screen, then take the same image over and over for about at least an hour (the longer, the better). This is best done with an intervalometer, but you can put your camera onto continuous mode, and use a shutter release cable.

4 Process the images

Back at your desk, download the free software StarStaX (www.markusenzweiler.de/StarStaX/StarStaX.html). Drag all the JPEG images into StarStaX, choose Gap Filling mode, and click Start Processing. In 10 minutes the software will have overlaid all the images to produce a dramatic star trail shot. You can now make a few image adjustments.