Stars

Weather conditions

To photograph the stars and the Milky Way, it is necessary first a clear night and if possible with a moon not very visible (avoid the evenings of full moon). Then find a place with little light pollution (more and more difficult to find).

The place

We must find a place with little light pollution (increasingly difficult to find) and having a foreground that will highlight the sky (tree, building, rock, ...). The star yarn will depend on the direction (N, E, S, W) and altitude with respect to the viewing horizon.

To determine altitude in degree, there is an approximate method (but largely enough). Use your fist. The height of your fist is about 10 °.

Without star trail

When using a camera on a tripod, the rotation of the Earth is not compensated. If we make a long pose the stars will no longer appear punctual, but will take the form of arcs of circles. If this effect makes it possible to obtain beautiful images, it is sometimes also desired to avoid it.

From the latitude of the location, altitude and direction, the software will calculate the declination. This will determine what the speed will be to avoid having a star yarn. The speed will not be uniform over the whole photo especially if you use a wide angle. It is for this reason that the maximum star-free time is calculated for each third of the image.

Depending on the end use of the photo, you will find 3 requirements criteria:

• Without star trail for A4 printing
• Without star trail for viewing with the naked eye on a screen in 100%
• Without star trail for viewing with the naked eye on a zooming screen

The result produces a neutral exposure in reasonably dark sky conditions. Results can appear brighter than natural but exposure can be pulled down in post processing.

Equipment

It requires a tripod and a camera, it is doable with any camera that has a manual mode and with which you can adjust the ISO manually, even if the best results will be obtained with a DSLR.

Choose a wide angle, not only to photograph the stars but also a little landscape.

A remote control or a self-timer

If you have a remote trigger remote control, then go out, this is the right time.

If you do not have one, simply set your camera to the self-timer. For example, at 5 or 10 seconds. In this way, your device will have a few seconds to stabilise between the moment you press the button (causing a small earthquake in the case) and triggering the shot.

The technique of shooting

Move your lens to manual focus and set the aperture to the smallest number your lens will allow you to achieve (ideal is to have an aperture less than or equal to f / 2.8).

Put your camera in:

• manual exposure,
• RAW recording,
• self-timer (2s, 5s or 10s),
• auto white balance

Don't be afraid to use a high ISO value. If you are concerned about noise, remember that you can correct some of it in post-processing (stacking technique).

Illustration of noise suppression by the stacking method. Left the original result and right by stacking it 9 times.