Shooting the Milky Way
The night sky has been an important part of humanity and civilization for tens of thousands of years. The Pleiades (Seven Sisters) have been used as a vision test for thousands of years: seeing six with the naked eye indicates perfect vision and seeing seven indicates above-average vision. However, over the last hundred or so the inventions of electricity and artificial light have somewhat robbed us of the mysteries of the celestial bodies. Because of light pollution, we can’t see the stars as vividly as we used to.
But where technology taketh, technology also giveth. We may have more overall light pollution, but today’s digital cameras can see better than man’s eye ever could. With a camera, tripod, Photoshop, and a few hours under the night sky in a dark part of the world, the Milky Way is in your sights.
Scouting a date and time
While technically viewable year round, you’ll have the best luck shooting great photos during the Milky Way “high season”: March thru October (in the northern hemisphere).
The Milky Way is only visible when the moon isn’t in the sky, because it’s so relatively bright. During a new moon, you can see the Milky way from dusk until dawn. During other phases of the moon, you can plan around moonset and moonrise. For example, if the moon sets at 1am, the Milky Way should be visible from 1am until dawn. TimeAndDate.com is a good resource for determining moonrise and moonset.
Scouting a location
There are two primary concerns when scouting a location to shoot the Milky Way: light pollution and cloud cover. You might have to drive a few hours outside of a major city for light pollution to be low enough to see the Milky Way. Check lightpollutionmap.info to find areas without light pollution. Cloud cover can be harder to plan for in advance; I recommend the Dark Sky app to check the day of.
One trick I learned recently in the ever foggy San Francisco: drive up Mt. Tamalpais in Marin, above the fog lines. You’ll enjoy clear skies, and the fog will trap some of San Francisco’s light underneath.
Milky way visibility
When you have a location (or more) scouted, one last task before the shoot is determining where in the sky the Milky Way will be. Two good options:
- Stellarium — Planetarium software for your computer
- Sky Guide — iPhone app
Given favorable circumstances, you can easily capture the Milky Way with an entry-level DSLR, kit lens and tripod. You don’t even need a DSLR; a mirrorless camera like Sony’s A6300 can work very well — provided that the chosen lens supports manual focus. Auto-focus won’t cut it.
To reduce motion blur and increase how much of the Milky Way you can capture, choose a wide-angle lens with a wide aperture. Some popular lenses for astrophotography:
- Canon 24mm f/1.4
- Canon 14mm aspherical f/2.8
- Canon 16–35mm f/2.8
- Tokina 11-16mm f/2.8
- Nikon 10.5mm f/2.8
The wider the aperture, the more light from the Milky Way will reach your image sensor. Around 24mm will fill your frame with the galactic core of the Milky Way.
A heavy, stable tripod is critical for photographing the Milky Way. You can tie a heavy object to the center pole of your tripod for added stability. You’ll also want to remove your camera strap, so that it doesn’t blow in the wind and wiggle the shot.
If you plan on stacking your images in post-processing — which I highly recommend — an intervalometer is incredibly helpful. It’s basically an auto-pilot for your shutter release; you can easily program it to take a photo every X seconds.
You’ll be using your camera in a pretty unconventional way, so first order of business is moving to manual mode to give you full control over the aperture, shutter speed and ISO.
- Focus: in manual mode, set your lens’ focus to infinity. It’s important to note that many lenses will focus beyond infinity, and will result in a blurry photo. For Canon and Nikon lenses there’s an easy trick: line up the main stem of the “L” with the focus point:
- Aperture: widest setting (i.e. lowest F-stop), recommended f/2.8 or wider. You won’t experience any depth-of-field bokeh effects at your widest aperture because the focus will be at infinity.
- ISO: this will depend on how well your camera handles low-light situations. I recommend starting at ISO 1600 and testing up through 12800.
- Shutter speed: this setting will be codependent on your ISO selection, but in general you can play with shutter speeds from 2s up through 30s. Shooting star trails will take a several minute long exposure.
RAW vs JPEG
I always advocate for RAW over JPEG in almost every situation, and night sky photography is no exception. By shooting RAW, you’ll have improved control over post-processing and end up with a better product.
If you’re not going to post-process at all, there’s actually an advantage to shooting JPEG over RAW. Some cameras have a built-in Long Exposure Noise Reduction (LENR) option that can enhance the quality of a JPEG capture. With LENR enabled, the camera snaps a photo, closes the shutter and takes another photo of “nothing”. That nothing is actually full of noise from cosmic rays hitting the image sensor. By knowing what the noise looks like, the camera can “subtract” away the noise.
To really bring out the beauty of the Milky Way, I highly recommend post-processing the RAW photo in Lightroom or Photoshop. A little bit of highlight, white/black levels, and saturation adjustment can go a long way. Working with a RAW photo gives you the maximum control out of your original image.
To further reduce the noise in your photos, you can stack them together and “average out” the noise (similar to LENR). Lonely Speck produced my favorite guide for stacking:
The basic idea is:
- shoot 5 or more “identical” shots (same framing, settings)
- load the images as layers in Photoshop
- align the images (because the Earth rotates a non-trivial amount)
- create a Smart Object with Median blending
You’ll need a fair bit of free disk space to accomplish this in Photoshop; in my experience, stacking 12 raw photos can take as much as 20 GB swap space. The process is similar to reducing noise in drone night photography.
It’s been surprising how accessible Milky Way photography actually is. You see all these amazing photos in your feed and can’t imagine being able to capture something like that. It turns out hardest part isn’t having the most skills or even the best gear, optimal settings, or post-processing touch — it’s the willingness to freeze in the middle of nowhere at 3am, staring at the night sky. But that’s also the most rewarding part.