HOW DO I FIND THE MILKY WAY?
The Milky Way spans between 150,000 to 200,000 light years and is composed of between 100 to 400 billion stars of which thousands may be visible to the naked eye. We’re located within the Milky Way, so we can see it all year round. However, for the best viewing, you want to see the spectacular the galactic centre – the Milky Way core which is only viewable for parts of the year – the Milky Way season. This period extends from around mid-January (before dawn) to mid-November (just after it gets dark) in the southern hemisphere. I know that sounds like almost all year, but the months on the ends are barely viewable. I will often be out in February and awake around 2-3 am photographing before dawn. As the year progresses, the galactic centre rises earlier and earlier through the night. It’s best seen mid-May to October because the core is viewable not long after it gets dark and the cooler temperatures result in a clearer sky. In the southern hemisphere, it rises from the south-east and 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 (don’t you love technology). I personally use Photopills and Skysafari. I find the advantage of Skysafari (IOS and Android) is that I find it very easy to visualise by pinching in/out the screen to suit the width of my lens focal length. For example, my 15mm lens on full frame covers a horizontal angle of view of 100 degrees, so it’s easy to see how the Milky Way will appear on the camera with an area of the foreground.
Photopills has loads of little apps inside it doing many different things. At the time of writing it has calculators helping with:
- DoF Table
- Hyperfocal Table
- Subject Distance
- Focal length match
- Night AR (augmented reality)
- Star trails
- Spot stars
Photopills looks a bit intimidating to begin with, like a tasting plate with too many options. However it’s best to learn a couple of the relevant “pills” and gradually explore the app.
There are plenty of other means to find out where the Milky Way core will be at different times of the year, but those are the two that I use the most.
There are other things to consider when working out the time to photograph the Milky Way including local weather, the brightness and location of the moon and light pollution where you are. Just because the moon is up, it doesn’t stop you from photographing. It’s more of how bright is it, the rise and set and how close it is to the Milky Way core. Some of my best photos have a slight moon and also even some cloud.
WHAT DOES IT LOOK LIKE?
What does it look like? You can’t see the Milky Way the same way that the photos portray them. This is because cameras are more sensitive than the eye and also our eyes cannot see the infrared spectrum whereas cameras are more sensitive to it. In the right conditions, you can see the Milky Way as a faint pale cloudy mass and can see the definition of the dust lanes of the galactic centre.
WHAT DO YOU NEED TO PHOTOGRAPH – BASIC ASTROPHOTOGRAPHY
Most of the astrophotography equipment is optional. All you need is a camera that you can manually adjust the exposure and focus. A Digital SLR or mirrorless camera is ideal. A tripod helps to keep to angle the camera and keep the camera steady. Ideally, your camera lens will have a wide focal length (low mm) and also a wide aperture (low F number). A cameras ability to photograph RAW images allows you to bring more out of the image in colour and contrast to match your creative vision.
HOW TO PHOTOGRAPH THE MILKY WAY
Landscape astrophotography preferably has some of the landscape in the foreground to create a sense of connection to the location. Have a look at your surroundings before it gets dark and work out your composition, it’s a lot easier to work it out before it’s too dark when visibility becomes a lot more limited.
The difficulty in focusing for astrophotography is that it’s dark and autofocus is not likely to work. Focusing on stars through an optical viewfinder is also going to have difficulty. Use the live view on the camera, zoom in and 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. With astrophotography images, you will typically notice out of focus stars more than you will a slightly out of focus darker foreground. If your camera struggles with this, you can try focusing on a star at dusk when the stars are starting to come out or on a distant object and mark/tape the focus for use later. Some lenses have a hard infinity focus which works. Make sure you turn off image stabilisation and autofocus.
Photographing at night is dark. You want to capture as much light in as possible to the camera. This is a balance between the aperture, shutter and ISO of a camera. I always photograph in RAW as well as it gives me the additional capability to process later.
Aperture – shoot very wide open on the lens if possible – this lets in a lot of light. The compromise here is that the wider the aperture, generally the softer the image or the shallower depth of field. With a wide-angle lens, most of the scene may end up in acceptable focus, especially if the foreground is not very close.
Shutter – you can let in more light to the camera by having the shutter of the length of time that the camera is taking an image – open for a longer period of time. However, moving subjects will result in motion blur if the exposure is open for too long. Because the earth is rotating, if you expose for too long a shutter speed, what will happen is that the stars will start blurring and creating star trails. To deal with this, there is a rule (guide) of 500. Take 500 and divided by the focal length (adjusted for your if the camera is a crop sensor). For example on a Canon crop sensor camera like the 80d 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.
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 going till it looks terrible.
White balance – When you’re photographing in RAW, you can change the white balance later. However, 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.
Something with landscape astrophotography is that the above is just guidelines and you can push the boundaries for different looks or use equipment (like tracking mounts) that allows you to do things like break the rule of 500. Try exposing for longer, don’t worry about a bit of star trailing, just see what it looks like.
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, using crescent moonlight and exposure blending.
That’s it for initial settings – there are many ways to go beyond such guidelines, but that’s for another day.