How To Capture Milky Way Images

Many digital cameras these days can do surprisingly well at capturing images at night. Their sensors are more sensitive than your eyes, especially at capturing color at night.

Photography has always involved multiple steps, with exposure being only one part of the equation. In the days of film, the darkroom enabled additional influence to be applied during development, and then again during printing. Unless you were using a Polaroid camera, there was no such thing as “straight out of the camera.” Maybe you trusted someone in a drug store to do your developing and printing for you, but that wasn’t an optimal situation and that certainly doesn’t mean that no adjustments were made. For the most part, the entire concept of “straight out of the camera” is a myth that is best set aside as soon and as thoroughly as possible.

Today with digital cameras your darkroom is on a computer, implemented in software. Milky Way shots are a great example of images that you won’t get the most out of until you get in the habit of spending 5 minutes in your digital darkroom to complete the photographic process.

If you find a dark place outdoors to shoot and you can make out stars and the lighter, more dense band of the Milky Way, a little postprocessing can get you a lot further. As with my previous blog post you need to shoot on a tripod, using manual aperture and manual focus. Having your long exposure noise reduction turned off is not critical since we’re dealing with single exposures for Milky Way shots.

Shoot with your widest focal length lens to minimize star movement in the field of view, have it opened to its widest aperture to minimize exposure time. You may still have little enough light that you shoot at the longest exposure time (generally 30 seconds) or you may need to shoot in “bulb” mode for a longer time in order to get enough light. Always shoot in RAW mode so you have far more adjustment capability in post-processing software.

Shoot near the date of a new moon, so there is as little light pollution as possible. The last thing you need to know, probably the most important thing during planning your shot, is how to predict when the most intricate, dense, bright center of the Milky Way is in the night sky! In Summer the sun is up roughly 2/3 of every day, but the Milky Way crosses the sky in the night. The center of the Milky Way is towards the constellation Sagittarius. You can look up the dates when Sagittarius is high in the sky, and that’s when the Milky Way is most intense: http://homepage.ntlworld.com/mjpowell/Astro/Sgr/Find-Sagittarius.htm
If you have a smart phone, you can also use astronomy applications such as StarWalk and change the date and time to see when the Milky Way rises on the eastern horizon.

In simple terms, it highest around midnight on the Summer solstice June 21, two hours later per month earlier (2 am in May), two hours earlier per month later (10 pm in July). So really your best shooting will be on days near the new moon dates, and preferably within 7 weeks or so of June 21:May, June, July and August.  If you want to shoot at night right after the sun sets however, instead of getting up in the early hours of the morning, the Milky Way doesn’t rise early in the night until Late May or so, which is why many people favor the summer months June through August for Milky Way shooting.

So lets assume you go out on the right night, shoot south towards Sagittarius, capture a RAW file with some stars showing, and maybe you can barely make out the bright stripe of the Milky Way and its slightly more dense center.

Well, if you were in a darkroom… how do you lighten the Milky Way while keeping the background sky dark? The simple answer is dodge and burn… selectively darken some areas while lightening others!

In Adobe Lightroom (download a 30 day trial if you don’t have it already, AFTER you collect some images to process) use the paintbrush tool (under the Develop module) to select and lighten the area around the Milky Way. Use the paintbrush tool to darken the sky everywhere else (this makes both the Milky Way and the stars pop).

to do even better, you can also increase contrast while performing these functions, further darkening background light levels, including noise. Adjust exposure and brightness so the fainter stars in the Milky Way get brighter while background and noise gets dark. You can increase saturation slightly on the Milky Way, but increasing contrast has that effect already, so you might not need to.

Don’t worry too much about how much noise your camera produces… after you adjust contrast and brightness, just crank up the noise reduction. After all, there isn’t generally much detail to lose by doing that. In Lightroom for dark, noisy photos I try to max out noise reduction at 25 or maybe 30, but when needed I’ll go as high as into the 60s (that was on my Canon 5D Mark II in 2009 – 2011, in 2019 I rarely have to go over 20 or 25 with newer full frame sensors).

Lightroom can also selectively adjust saturation and brightness of individual colors. If you shoot too close to sunset and “blue hour”, or during a too-bright moon that is too full (and creating blue night sky), it can be handy to darken a blueish background sky to help separate that from the stars (just did that on a star trails shot). On the other hand for dark new moon skies, like you should have if you’re planning ahead for Milky Way shooting, there is little or no light scattering turning the sky blue. A lot of the Milky Way stars have a slight blue tint though, so selectively raising brightness of blue can help separate them from dark background and any noise.

What color there often is in the night sky is “aurora green”. it’s produced by airglow, a chemoluminescence of oxygen, similar to aurora. Like aurorae, you can even see airglow move in the sky from image to image if you capture many images in a row and convert them to a time-lapse video.

It’s a balancing act between white balance, adjusting individual colors, and tweaking the brightness and especially contrast of the area the Milky Way covers, but you can find a reasonable compromise pretty quickly. Once you do fairly well adjusting one shot, Lightroom enables you to copy your develop settings and apply them to additional photos.

There are other subtle tricks of course, and the tools and skills are always evolving, so there is a lot of information to convey and I cover a lot more in my night photography workshops.  Check the links at the top of the front page of this blog for upcoming dates.