A Beginners Guide to Milky Way Photography

How to find and photograph the Milky Way 

I love looking up in the night sky and spotting constellations, especially when I'm in a dark sky area. It is something I seem to do on holiday, often in other parts of the country / world to my normal environment. I hadn't really thought I could spot the milky way at home, in my own garden. I live near two decent sized towns and there is quite a lot of light pollution. However, over that last few months I have discovered that I can actually see, and better still photograph, the milky way from my own back garden!

The milky way and a meteor 

This revelation came about when I first attended a short online class on finding and photographing the milky way.  I learned when and where to look for the milky way, what impact the phase of the moon has on what can be seen together with what camera settings to use. See this blog post for more about the course (near the end of the blog post).

I live in the northern hemisphere so on a clear night I need to look to the south east, then south west as the night continues, as this is where the galactic centre of the milky way can be found (the brightest part of the milky way). I believe in the southern hemisphere it is positioned directly overhead.

There are apps to help you locate the milky way such as PhotoPills and Stellarium  these can show you what constellations you are looking at. You need to find the constellations of Scorpius and Saggitarius. Scorpius has a bright star called Antares that is visible with the naked eye. This will be to the right of the galactic centre (as you look at it). Saggitarius is situated almost at the brightest part of the milky way a little to the left as you look at it. The stars of Saggitarius form a shape a little like a teapot with the spout at the bright part of the milky way.

The milky way is not visible all year round. It can be seen from February but it is very low on the southern horizon. It moves higher in the sky as the year progresses.  Starting in June it's best visibility is early in the night, as soon as it gets dark, when it is closer to the horizon and you can watch it rising, moving upwards and to the west later in the night. From July it will already be high in the sky by the time it gets dark.  It gets lower in the sky from August and is visible, if conditions are good enough, until November.

The brightness of the moon affects the visibility of the milky way so avoid the full moon. The perfect moon phase is a new moon as the sky remains dark throughout the night. Another thing to check is when the moon will rise and set. It if doesn't rise until after midnight you might be able to get a good look at the milky way earlier in the evening about an hour and a half after sunset.

The next thing to check is the weather, if there are clouds you won't be able to see it. You need a clear sky and preferably a thin or non existent moon. I use an app on my phone called Clear Outside which shows times of sunset, moon rise / set, moon phase in the area you are photographing plus the level of cloud, wind and rain. It is really useful as a planning tool.

The milky way

If you are in a place with light pollution you might not see the milky way clearly but your camera might still be able to capture it.  Find a sheltered spot to set up your tripod, maybe behind a wall, where local lights are blocked out from the camera.

Once you know where to look and you have a clear sky with no moon it is time to set up your camera.

The idea is to allow as much light as possible into the sensor so you need a wide open aperture, as wide as your lens will go (f2.8 or wider if possible), you will need to bump up the ISO to maybe 1600 or more. If there is light pollution the ISO can be lower. White balance should be between 3000K and 4000K again, depending on local light pollution, or just leave the white balance set to auto and correct colours in post production. I use Lightroom for this.

Next the shutter speed. You need a slow shutter speed to capture as much light as possible but be careful, if you want pin sharp stars you need to keep to under 20 seconds. The actual calculation can be done and it depends on the camera model aperture and sensor size so it's not easy to calculate but there is a link here if you want to know more. A simple way to calculate this is to divide 500 by you focal length x sensor crop factor.

Shutter speed = 500 / (focal length x crop factor)

so for my Canon EOS camera which has an APS-C sensor that has a crop factor of 1.6 and using my 18:135 mm lens at 18 mm focal length I would use

Shutter speed = 500 / (18 x 1.6) which is 17.36 seconds maximum.

I would recommend taking a few test shots at different speeds to check which works best for your camera and lens.

If you want star trails then a slower shutter speed will provide these,  as the earth rotates the stars appear to move across the sky from left to right.

Finally focus is the big issue at night. Use manual focus and turn the focus to the infinity symbol and take a test shot.  Check this by zooming in and adjust the focus close to the infinity symbol, this varies with different cameras. Once you have the stars showing sharply don't move the focus ring again.

Due to the fact that exposure time will be in seconds you must use a tripod and also use a shutter delay or shutter release if possible to minimise any camera shake. 

I don't have any astrophotography gear so can't comment on the use of star tracker equipment but as you develop your interest in astrophotography this might be something you would like to invest in.

What happens afterwards?

Stacked images

I use Lightroom to bring out the colours and try to minimise the light pollution and that is basically it for me.  However if you take a number of images with the same setup you can use software to stack these together to create an improved  milky way image, Starry Sky Stacker is a great app to use if you have a Mac or try Sequator for a Windows computer.

You can also use this technique for other celestial events, such as the recent comet that was in the northern sky.

Neowise comet

Good luck with your milky way photography.