On the hunt for the Milky Way

Pictures of the night sky seem to hold great allure for us. Perhaps that’s because it’s becoming harder and harder for many people to get a clear look at the stars in a time of increasing light pollution. When I upload a night-sky photo on social media, I always get a disproportional response. People often ask how the picture came to be. But a photo of the starry sky isn’t yet something we can replicate with a smartphone. If you want a successful photo, there are a few things you have to consider. The process begins with equipment, choice of location and subject, the camera settings, and ends in post-production. In this article, I’ll give you a few tips that’ll hopefully amount to a crash course in night sky photography.

There are a few things you can’t do without when photographing the night sky:

1. Tripod: An absolute must, since at night you’ll regularly need exposures several seconds long.
2. Remote release: Helpful to avoid camera shake when releasing the shutter. Many new cameras can be released over WLAN using a handy smartphone app. Alternatively, you can use the camera’s built-in 2-second timer. You’ll also need a remote release in most cameras for exposures above 30 seconds in ‘bulb mode’.
3. Light: To be able to see the stars clearly, you’ll have to find places where it’s really dark. So that you don’t lose perspective while you’re doing that, you need a light source. A hat with a light on it has the advantage that both hands are kept free for operating the camera. A ‘night vision mode’ is also useful, in which the camera emits red light. It’s not as bright as white light, but it doesn’t cause the eyes to lose their night vision. Also, the light can be used creatively in the picture (“light painting” is a key word here; more on that later).
4. Camera: Camera sensors are so good nowadays that you can take night-sky photos even with an entry-level camera. A larger sensor will take in more light and so handle noise better, so a full-format camera will give you another leap in quality. Personally, I use a Canon EOS 6D.
5. Lenses: Just like for the camera, in good conditions, even a kit lens will get you usable results. But for better quality, you want a lens that will let in as much light as possible - use a fast lens with a large aperture (f/2.8 or larger if possible). My absolute favourite for night-sky photography is the Tamron 15-30mm f/2.8 ultra-wide angle lens. It’s not only very fast, but the short focal length means you capture an unbelievable amount of the sky in the picture and you can use longer exposures before the earth’s rotation causes the stars to leave trails (more on this later as well).

You don’t have to be an astronomer to know that the chances of finding a clear night sky, and especially of capturing the Milky Way, in a city with the naked eye are slim to nothing. The buzz phrase is ‘light pollution’, and it’s caused by artificial light sources, whether street lights, car headlights or neon signs. For night-sky photography, we need to get as far away from the light pollution of big cities and towns as possible. For me, coming from Heidelberg, that means getting out of the Rhein-Neckar delta and as deep as possible into the Odenwald or Pfälzer forest. A map (like this one: www.lightpollutionmap.info) can tell you the places with the lowest light pollution near you.

As for the best time, two things are most important to think about:

1. The clearer and more cloud-free the night, the better, so have a look at a weather forecast beforehand. Of course, you can’t rely on these 100%. If you see a couple of clouds in the sky once you get there, that’s no reason to immediately set off back home. Sometimes, one or two clouds can give your photos that special something that they’d otherwise lack.
2. Note the phase of the moon. A bright full moon can make a compelling subject for a photo, but it will also outshine the stars. That means if we’re hoping to get a glimpse of the Milky Way, we want as close to a new moon as possible. I highly recommend the app PhotoPills if you want a handy overview of the phases of the moon and lots of other useful information as well. It even has an augmented reality function that’ll help you find the Milky Way in the night sky using your phone’s screen, which I think is great.

If we’ve followed the tips until now, we are now sitting with tripod and camera complete with fast lens, on a clear night complete with new moon, in a dark place far away from civilisation. Under these conditions, we are looking up at a magnificent night sky. We can probably even see the course of the Milky Way with the naked eye. But as stunning as the night sky is, just pointing the camera upwards and taking a picture would be a bit boring. Our picture would benefit from an interesting foreground subject to place the starry sky in relief, emphasise the breadth of the universe and lend context to the whole photo. We have any number of options for this: trees, buildings, lakes, mountains. When I’m out and about, I’m often on the lookout for potential subjects. Trees work particularly well, for instance, when they’re standing on their own and make a stark outline above the horizon. But if no suitable subject is to be found, don’t despair: there’s always yourself! Why not take a selfie under the night sky? If you use several seconds’ exposure time, however, make sure the air is still, so that the photo isn’t blurry. 

A technique you can use to make more of the details on your foreground subject visible is “light painting”. Use a torch to light up your foreground during a long-exposure photo. You’ll probably have to experiment a bit with the level of light you use and how long you light up your subject so that you get the right amount of light. Personally, I don’t use the technique that often because the effect often looks too unnatural. If you make sure your subject is outlined well against the horizon and the sky, you can then deliberately under-expose and capture a beautiful silhouette.

Which brings us to the next point: camera settings. First of all: shoot in RAW format if possible. You’ll get a kind of digital negative that hasn’t been processed by the camera’s software. This leaves you significantly more leeway during post-processing on the PC.

At night, forget your camera’s automatic exposure settings and go straight into manual mode. It’s best to set the focus manually as well, since autofocus usually doesn’t work in dark conditions. So that the stars come out sharp, set focus to infinity. To do this, I focus on a particularly big and bright star in live view and then magnify it to maximum using the magnification function. Then, turn the focus ring until the star is as small and dot-shaped as possible. That’s when you’ve got it in perfect focus.

Note the following when setting the exposure:

1. Aperture always as wide as possible (you’ll remember that that lets in the most light)
2. ISO usually between 1600 and 3200; depending on exposure and focal length of the lens, higher or lower values might be necessary for better exposure
3. Length of exposure: generally, you want the longest possible exposure, as this lets in the most light and minimises noise, improving picture quality. However, the maximum exposure setting will be limited by the earth’s rotation. Dot-shaped stars will turn into lines, which is usually undesirable (unless you’ve decided that a ‘star trail’ photo is what you want). How long you can expose before star trails start to appear will depend on your focal length. As a rule of thumb, the maximum exposure time in seconds = 500/focal length. You’ll also want to multiply the focal length with the crop factor of your camera if you’re not working with a full-format camera. Example: if I use my Tamron 15-30mm at 15mm on the Canon EOS 6D (full format), I can expose for 500/15 = 33 seconds maximum. With the same lens on my EOS 7D Mark II (APS-C, crop factor 1.6), it’s only 500/(15x1.6) = 21 seconds.