This article was written by Michael Goh; photographer and astrophotography enthusiast.
Around 200km north of Perth, hundreds of limestone pillars protrude from a vast yellow desert. These are the Pinnacles of the Nambung National Park. The remote location, far away from the bright city lights makes it a spectacular location for star gazing and night photography.
How do I find the Milky Way?
The Milky Way spans between 150,000 to 200,000 light years and is made up of between 100 to 400 billion stars, of which thousands may be visible to the naked eye in the right conditions. Standing in a dark location with the majestic view of the Milky Way is a truly humbling experience.
We’re located within the Milky Way, so we can see it all year round. However for the best viewing, we want to see the spectacular galactic centre - the Milky Way core. This is only viewable for parts of the year - the Milky Way season. This extends from around mid-January (before dawn) to mid-November (just after it gets dark) in the southern hemisphere. As the year progresses, the galactic centre rises earlier and earlier through the night. It's best seen between mid-May to October because the core is viewable soon after dark and the cooler temperatures results in a clearer sky. In the southern hemisphere, it rises from the South East, rises up into the sky till it is directly above (the Zenith) before moving to set in the West. It's easy to plan the Milky Way location in the sky with apps. I personally use Photopills and Skysafari. Be aware of the moon phase as a bright moon will affect viewing.
What does it look like?
You can't see the Milky Way the same way that photos portray them. This is because cameras are more sensitive to light and the infrared spectrum than our eyes are. In the right conditions, you can see the Milky Way as a faint but clearly defined pale cloudy structure.
What do you need to photograph?
You will want to have a camera that can manually adjust the exposure and focus. A Digital SLR or mirrorless camera is ideal. A tripod will help to keep the camera steady. Ideally your camera lens will have a wide focal length (low mm) to cover a wider area of the sky and a wide aperture (low F number) to let in more light.
How to photograph the Milky Way
On the camera use live view and zoom in to focus on a bright star. It doesn't have to be in the same direction as you are photographing as all the stars are in the same focus. If your camera struggles with this, you can focus on a star at dusk (when it’s still light) or on a distant object and mark/tape the focus for use later. Make sure you turn off image stabilisation and auto focus.
Because it's dark, the idea is to capture as much light as possible to the camera. There is a fine balance between the aperture, shutter and ISO of a camera.
Aperture - shoot very wide open on the lens if possible (lower F number such as F1.4 F2.8 or F3.5) to maximise the amount of light that enters the camera. The compromise is that the wider the aperture, the image will be less sharp.
Shutter - you can let in more light into the camera by having the shutter open for longer. However if you leave the shutter open for too long, then the motion from the Earths’ rotation will result in star trails. To deal with this, there is a rule of 500. Take 500 and divided by the focal length (adjusted for your if the camera is a crop sensor) and this is how long you can expose for before noticeable star trails. For example, on a crop sensor Canon camera (crop multiplier of x1.6) with an 18-55mm lens - you may photograph at 18mm. Using the rule of 500 you would divide 500 by 18 (mm) and divide by the crop multiplier (1.6) which would be 500/18/1.6 = 17s. I would be quite comfortable photographing at 15-20s. On a full frame camera with a 15mm lens you would have 500/15 = 33s.
ISO - generally the lower the ISO the better as it provides a less noisy image. However due to the physical limitations of the aperture and the shutter, the next area that we can change is the ISO. With my full frame camera, I'm often photographing between ISO 3200 and 12800. With my crop sensor camera - normally ISO 1600 to 3200. There are many factors involved with noise in the image so I suggest taking multiple images at a range of different ISO settings. Keep increasing the ISO until it looks terrible.
White Balance - When you're photographing in RAW, you can change the white balance later. I normally photograph at a white balance of 4000K as I feel it is closer to what the Milky Way looks like. If your camera doesn't support colour temperatures, then you can photograph at Fluorescent which provides 4000K but makes the image a bit more magenta.
With landscape astrophotography the above are just guidelines and I recommend that you can change the settings for different looks. There is also equipment such as tracking mounts that allow you photograph for longer without causing star trails.
So you've taken a photograph but the foreground is too dark and you want to brighten it? There are multiple ways to deal with this including light painting the foreground by using a torchlight and quickly lighting the landscape.
Make sure you turn off the lights and just appreciate the stars in the location.
This story was written by Michael Goh; professional photographer and astrophotographer. The activities recounted in this article were experienced independently of Australia's Coral Coast. Australia’s Coral Coast did not review or approve this article.