Hi! My name is Henri. I am a student here in St Andrews and a professional landscape photographer and videographer originally from Somerset in England. I have worked with a variety of brands and companies to produce content and have been lucky enough to travel all over the world for my photography.
Photographing the night sky is one of life’s simple pleasures. Braving the cold nights and unsociable hours to shoot the phenomena that so many take for granted makes this one of the most rewarding types of photography. Whether you are staying up late to glimpse the Milky Way in all its splendour, capturing the International Space Station flying across the sky, or even getting out of a warm bed in the middle of the night at the slightest possibility of seeing the aurora, this is a way of life that I highly recommend you partake in and enjoy. Always have your camera batteries charged and your gear by the door. Trust me when I say it’s infectious.
In St Andrews, we are fortunate to have the possibility of seeing glimpses of the aurora during the winter months and the Milky Way is certainly visible on any clear, dark night. I implore you to get outside and enjoy the fresh sea air at a time when few people ever experience it.
This article will explain the basic equipment required to shoot the night sky, the fundamental ‘Exposure Triangle’, how to set up the shot and how to edit the final result.
Aurora Borealis, Egilsstaðir, Iceland. f/3.5, 25 second exposure, ISO 800.
What EQUIPMENT do I need to start photographing the Night Sky?
Provided you have a good enough camera, there are only a few pieces of inexpensive equipment required to absolutely transform your astrophotography.
- Any camera that will allow you to put it into Manual mode is a great starting point, whether it be a DSLR, mirrorless, bridge or compact. Sadly, this is a field where the ever-popular smartphone just won’t cut it.
- A stable platform/tripod for longer exposures to prevent motion blur.
- A lens – as wide as possible to capture as much of the sky as you can. A lens with the widest aperture (lowest f/value) is best.
- An intervalometer – a cheap device that plugs into your camera, allowing you to control the shutter remotely to prevent touching the camera during an exposure. Whilst not essential, this can be helpful when you get more confident and want better results.
- A spare battery – long exposures can really sap the battery life, and being outside in the cold also means the battery will deplete quicker.
- A phone app such as SkyGuide to help you easily locate The Milky Way and other phenomena.
- A clear night with no visible moon (see below) – unless you want to photograph the moon, it tends to look like the sun in long exposures and will make it more difficult to see stars, the Milky Way and aurora. The darker the better.
Long Exposure of the sky before sunrise, showing the effects of the moon on the image. Mount Roy, Wanaka, New Zealand.
APERTURE, SHUTTER SPEED AND ISO – ‘THE EXPOSURE TRIANGLE’
The three main pillars of photography are often known as the ‘Exposure Triangle’. They constitute the basic elements that must be taken into account in Manual mode and are especially relevant at night. Given that the fundamental principle of astrophotography is to let as much light as possible into the camera, these three elements are absolutely crucial.
It’s time to get out of that wretched Auto mode and ‘point-and-click’ way of thinking.
In Manual mode, the aperture, shutter speed and ISO can be adjusted individually, whereas in Auto mode, the camera decides on all these values itself, not necessarily choosing the right options.
Aperture, measured in f/ values, can be compared to the iris of your eye closing and opening to let light beam onto your retina (i.e. the camera’s sensor). In exactly the same way, if you have a bright object in front of you, you’ll need a narrower aperture (a higher f/value) to decrease the amount of light reaching the sensor and for a darker object, you’ll need a wider aperture (a lower f/value). The night sky is a very dark subject. This means we will want the widest possible aperture to let in more light. If your camera can go down to an aperture of f/1.8 – 3.5 this is the ideal aperture for shooting at night. Aperture will also affect your depth of field (what’s in focus and what’s not at one time), though this isn’t as important for astrophotography.
Another way in which we can maximise light is through the shutter speed. This corresponds to the length of time that the camera shutter is open, allowing light to reach the sensor. Simply put, the longer the shutter speed, the more light is captured, thus the brighter the end result. “Why not just have a really long shutter speed to let in loads of light?” I hear you ask. Because the Earth is constantly moving, a shutter speed longer than around 25-30 seconds at night will cause ‘star trails’ to appear – streaks of light formed as the stars move across the sky. Unless this is the desired effect, aim on keeping the shutter speed within 15-20 seconds to retain pin-point sharpness.
The last element of the triangle is ISO. This is a standardised industry scale for measuring sensitivity to light. If the ISO is increased, then so will the sensitivity of the sensor to light and thus the end result will be brighter. However, ISO should always be kept as low as possible as increasing it will cause noise and colour degradation. At night, to keep the image as clear and crisp as possible, try to avoid exceeding ISO values of 1000.
When combining all three of these things, an element of compromise is needed. Play around and see what gives you the best results.
The Milky Way, Franz Josef, New Zealand, f/3.5, 20s exposure, ISO 800.
The Milky Way, Waikawau Bay, New Zealand, f/3.5, 22s exposure, ISO 800.
FOCUSING, SETTING UP THE SHOT AND EDITING
To set up the shot, first check where The Milky Way is in the sky. If bright enough, it may be visible to the naked eye, though often it is not. The lens should be set to Manual Focus and set to Infinity in order to focus on the stars. Most often denoted by the infinity symbol, this can be found on the focusing ring on the front of the lens and is a very important step if you want sharp photos. After this, place the camera on a sturdy platform and put it in manual mode. Using the camera settings above, experiment and see what you can shoot. Remember to shoot on a moon-free night and ensure the file format is set to RAW.
When it comes to editing, the RAW format will allow for much greater flexibility when adjusting parameters such as brightness and saturation, without the same degradation present in a JPEG file during editing. The key to editing is to merely enhance what is already there as opposed to adding anything artificial.