Our small blue planet is located on a spiral arm, far out from the center of the Milky Way Galaxy. When we look towards the galactic center, we can view one of the most spectacular sites imaginable. Thousands of stars are clustered together, to form a hazy band in the sky, known simply as the Milky Way.
If you enjoy photographing the Milky Way, the winter months can seem especially long. During this time, the Earth is pointing away from the center of the galaxy at night, and you can only see the fainter parts of the Milky Way. It can still be photographed, but the shots won’t likely be as dramatic as they are at other times of the year.
Fortunately, the bright galactic center becomes visible again in the spring. In March, it rises shortly before dawn in the Northern Hemisphere. So you will need to stay up all night or get up very early to photograph it. Every day, it rises a little earlier in the night, and by June it will be rising about the same time that the sun sets.
The great thing about photographing the Milky Way in the spring and early summer months, is that you can capture the full band of the Milky Way arcing across the sky. By August, the Milky Way will appear too high in the sky, in the Northern Hemisphere, to capture the full arc.
If you’re shooting from the Southern Hemisphere, you will have a longer time frame to see the full band of the Milky Way. From about February to June, you can capture it in the southern part of the sky, just after the galactic center rises above the horizon. From about June to September, you can capture it just before it sets in the west.
Since the Milky Way spans such a large portion of the sky, you will need to stitch together multiple images to capture all of it in one photograph. I explain how to do this below.
There is some specialized equipment you can use to capture stitched images of the Milky Way, such as a panoramic tripod head, a leveling base, and even a robotic camera mount. However, the majority of the time you won’t need any special equipment. Anyone with a good tripod and a DSLR can capture the full arc of the Milky Way.
You can use any lens from about 14mm to 50mm to capture your images. If you use a longer lens, like 50mm, you’ll need to take, and stitch, a lot more images together. This can be more time-consuming, but you will also capture much larger image files, with greater detail and less noise.
Ideally, you’ll want to use a lens with a very wide aperture, like f/1.4 or f/2.8. It is also helpful to have a tripod with a bubble level on top of its legs, and a tripod head that has a rotating base.
PLANNING YOUR SHOTS
You can pre-visualize how the Milky Way will appear at any time and location using a program called Stellarium. This program can be downloaded for free, it can also be purchased as an iTunes or Android app, or you can use other apps like PhotoPills or Sky Safari.
You will usually want to shoot images of the Milky Way under no moon. If the moon is out, it will obscure the stars, and the Milky Way will not look as impressive. One exception to that, is if you want the moon to illuminate the foreground. You can shoot with a waxing crescent moon that is about 20% illuminated. You’ll need the moon to be directly behind you so it obscures the stars as little as possible. The moon will be in a good position for this shortly after it gets dark on July 8-9th, 2016.
You will want to get far away from any city lights when shooting images of the Milky Way. Light pollution can create an unnatural color cast in the image and it can obscure the Milky Way. And, of course, you should check the weather forecast to make sure there will be clear skies.
Once you know how the Milky Way will appear, and have determined the best time to shoot it, you need to decide where to take your photograph. Although the full band of the Milky Way can be spectacular on its own, your images will be more compelling if you include an interesting foreground. If you’re in the Northern Hemisphere, you should find a composition facing east, since that is where the shallow arc of the Milky Way will be visible shortly after it rises. If possible, I recommend arriving before it gets dark to set up your shot. It’s much easier to determine the best composition, and focus your camera, when it’s still light out.
You can use the rule of 500 to calculate the exposure time for your images. Simply take 500, divided by the focal length of your lens, to get the number of seconds to expose the shot. For example, if you’re using a 50mm lens, take 500, divided by 50 = 10 seconds per exposure (this will give you long enough exposures to get good quality images at night without small star trails starting to appear in your shots).
You’ll typically want to use the widest aperture on your lens when shooting stitched images. You’ll also want to use the highest native ISO, that doesn’t cause any highlights to be blown out. As long as you don’t have any close foreground objects in the shot, you can focus at infinity.
You can do this by autofocusing on the moon if it is out, or by focusing on a very distant object before it gets dark. Switch to manual focus afterwards to make sure the focus stays set at infinity. Alternatively, if you have Live View on your camera, you can use it to zoom-in on a star on your LCD screen, then adjust the focus manually until the star appears as a small, sharp point of light. Don’t rely solely on the infinity marker on your lens, as it isn’t always accurate.
I’ve found that a white balance of about 3800K works well at night with no moon out. However, as long as you’re shooting in RAW (or if you do not have the K setting on your camera), you can set it to Daylight and adjust the white balance later.
Turn off Long Exposure Noise Reduction, as it can take too long, causing the stars to move too much between the exposures, and making it difficult to stitch the images together seamlessly.
TAKING THE PHOTOS
You will need to make sure that your camera is straight, using a bubble level or your camera’s built-in levelling feature. Ideally, you’ll also want to make sure your tripod head is mounted on a level surface by using a bubble level on top of your tripod legs, or a levelling head. This will ensure that your camera remains level as you turn it.
Before beginning the stitched image, I recommend taking a test shot. Point your camera towards the brightest part of the scene you will be photographing, and take an image using the camera settings you have chosen. Check the histogram to make sure you are not overexposing the image. If you are, lower the ISO until you are not clipping any of the highlights. You’ll also want to zoom in on your shot, and make sure everything is in sharp focus.
If everything looks okay, you can start taking your stitched image. I always recommend capturing a wider view of the scene than you want in your final image. You’ll have to crop the image afterwards, since the stitched images will never be perfectly rectangular. So it’s always better to capture too much of the scene, than too little.
Position your camera to take an image of the far, bottom left corner, of the scene you want to capture. After you take the first shot, you’ll need to quickly rotate your camera to the right before taking the second shot. Make sure and leave plenty of overlap (about one third of the scene) between the images to make it easier for the software to stitch the images.
Now, continue taking shots, and rotating the camera to the right, until you’ve captured the entire horizontal field of view that you want. To get the full band of the Milky Way, you’ll typically need to shoot a multi-row panorama. You can rotate the camera up and then shoot a second row of images. Keep doing this until you’ve captured the entire vertical field of view you want.
STITCHING WITH LIGHTROOM
You can stitch images within Lightroom CC. Simply select all of the images you want to stitch, right-click on them, and select Photomerge > Panorama. Lightroom will then attempt to stitch the images. Occasionally, Lightroom will be unable to stitch them together. If this happens, I recommend trying a free program for PCs called Image Composite Editor.
Once the images are stitched, you can process them like any other image.