Getting started with astrophotography
There’s something awe-inspiring about being out in a dark landscape and gazing at stars trillions of miles away. The nearest star aside from our sun is over 4 light years away, meaning the light that we see today is reflecting from the star from 4 years ago…we are literally seeing into the past! Beyond that, we are actually made up of stardust that is as old as the universe, so it’s only natural that we have an affinity for the stars!
Welcome to Astrophotography! Consider this post a primer on nighttime photography that will hopefully inspire you to get out under the stars, and take your own astro photos! It is intended to give you a general understanding of what is involved in night photography as well as some tips to start with. This is the first in a series of posts that will get more in depth as we go and cover topics like best shooting conditions, capturing star trails, planning and shooting a Milky Way shot, and post processing techniques such as stacking images and panoramas. With that, let’s dive in.
Find a dark sky
First things first, you aren’t going to see the stars by looking up at the sky in your Lincoln Park apartment in Chicago. You’ll be able to capture a glimpse of the Milky Way near a city, but it’s not going to be the spectacular shot you’re hoping for. If you can still see glimpses of city light in the sky, the camera will see it much better and it’ll overpower the image. For a truly great view of the Milky Way, you have to find a dark sky area and to do that I recommend going to dark site finder for a great map showing light pollution. Red, orange, and yellow areas have lots of light pollution and won’t offer much. Getting into the greens and blues and beyond will yield great results. These are the areas I can’t get enough of.
Check the weather
You could be in the darkest area in the world, but if it’s cloudy you’ll see nothing but darkness. Always keep an eye on the weather when planning a night photo shoot. My favorite site for checking the weather before a shoot is clear dark sky. Not only does it tell you the temperature, humidity, and wind, but also darkness, cloud coverage, and transparency. It gives a great astronomer’s forecast for the next 48 hours to help you predict clear and dark skies for a particular observation area. This is one of my go-to’s for planning. It can be frustrating to have the perfect location picked out and the date set, and then have the weather not cooperate, so it’s a good idea to plan out multiple, potential locations where the weather might be different.
Milky Way or starry night?
The time of year and the phase of the moon are two big factors to consider. If your goal is to get a stellar Milky Way shot then you’ll want to get the shot during a new moon (no moon present). There is some leeway here, you can still get great shots about 4 days on either side of the new moon and there are always exceptions, but it’s a good rule to live by. Also, in the northern hemisphere the galactic core, which is the brightest part of the Milky Way, isn’t visible in the winter months. April through July is the prime time. If in the southern hemisphere, the exact opposite is true.
If you want a classic streaked star trail shot then this is a case of more is less, or is it the other way around? Anyways, if you’re going for star trails, you generally don’t want the Milky Way in the frame. Doing a trail shot with the Milky Way in the frame typically leads to a bright blurred band where the Milky Way was, surrounded by dense streaks of swirling light. There are multiple ways of actually shooting a star trail shot, which we’ll get into in a later post, but for now, just go with the approach of shooting one long exposure.
Things to bring
- Camera with manual settings
- Widest and fastest lens you have. I recently started shooting with the Rokinon 14mm f/2.8 and love it for astrophotography
- Camera remote (optional, but recommended)
- A headlight! Unless you have superhuman vision and can see in the dark, a headlight is necessary. A flashlight will work, but the ability to have your hands free while using a headlight is phenomenal. I recommend picking one up with a red light function so you don’t ruin your night vision (and other photographers’ around you!). That being said, be mindful of others around you so your light doesn’t affect others negatively. Take time to learn your camera so you can make adjustments without needing a light
- Warm clothes! Even in the desert it can get cold at night
Scope out your spot at LEAST an hour in advance. Finding a good composition can be hard, finding a good one in the dark is much harder! Getting to your location before it gets dark gives you more time to explore the area and increase your chances of coming away with a photo you’re proud of.
I highly recommend shooting in RAW format rather than jpeg. If you plan to do any sort of editing of your images after the shoot, I ALWAYS recommend shooting in RAW. It will give you a lot more data to work with, and allow you to make more adjustments after the fact than jpeg will. If you want to read more about RAW vs jpeg, check out this article.
A tripod is one of the most, if not the most important piece of capturing star photos. Without a tripod, there’s no way of capturing a long enough exposure without introducing lots of blur from camera movement. Have a stable tripod that isn’t going to sway or move during a long exposure.
Any micro vibration of your camera will show up in your image. Bumping the camera will cause major blur, but even vibration from the shutter opening and closing can cause your images to be less than tack sharp. A trick to reduce vibrations and ultimately give a sharper image is to use a cable release or remote control. I also recommend Mirror Lockup (MLU) mode if your camera offers it. MLU flips up the camera mirror the moment before the picture is taken to allow for vibrations due to mirror movement to dissipate first.
Compose the shot
Since it’s so dark autofocus will be useless, go ahead and switch to manual focus now. Critical focus can be really challenging when it’s pitch black out. If you have a live view mode, the easiest method is to turn your ISO way up to brighten up the scene as much as possible. Then find the brightest star in the sky and focus on that.
There are a LOT of star photos out there, so do something to make yours stand out! Even though the photo is all about the stars, try to add some interest by composing the frame with an interesting or unique foreground element to really make the photo pop. It could be anything from an old decrepit barn, a field of wildflowers, a glowing tent, or anything else you can think of!
Framing a shot in the dark can be challenging (which is why you should try to arrive early!) and takes time. Taking a 30 second shot to test your composition is really time-consuming, so what I like to do is crank up my ISO to something like 16,000 and drop my exposure time to around 8-10 seconds. This gives an awful image, but it is good enough to see your composition, make an adjustment, and repeat until you get the composition you want. This method saves a ton of time.
If you’re afraid to shoot in manual mode on your camera, now is the time to overcome that fear! Take a deep breath and move the control dial from ‘auto’ to ‘M’. Without knowing anything about your camera and lens setup I can still make a solid guess for starting parameters for you to use. No, I’m not some psychic camera guru, it’s just a solid base exposure that will help you dial in your final settings more quickly.
Basic starting settings: 25 second exposure, f/2.8 (or the smallest f-number for your lens), and ISO 6400. On a dark night, this should make the Milky Way magically appear on your screen! If your image is too dark, you can do three things, increase the exposure time, increase the ISO, or both. Remember that increasing the exposure time will create longer star trails and that increasing the ISO will increase the noise in the image. It’s a balancing act to get the settings right, so play around until it starts to make sense and you like what you see.
This is personal preference, but I like to set my white balance to 3900K to give the Milky Way a slightly blue temperature. If you shoot in RAW, this can be changed in post processing, but if you shoot in JPEG then what you see is what you get.
Another setting to consider is in camera Long Exposure Noise Reduction. I recommend turning this OFF. The camera can do a pretty good job of reducing noise in the image, but at the cost of time. For example, say you have noise reduction turned on and you take a 30 second exposure, you wait 30 seconds and you hear the shutter close. But you can’t see your image! The camera will be inactive for an additional 30s while it performs noise reduction. This wait time can be painful, especially if you are shooting a 2 hour star trail photo and then have to wait an additional 2 hours for noise reduction! For that reason, I recommend turning it OFF and doing noise reduction in post processing.
The human eye captures and processes a scene very quickly, so not all of the visible light around us can be captured, leaving detail unseen. The camera, on the other hand, allows us to essentially time travel. We can leave the camera shutter open as long as we want (until the battery dies) and let the light pile up to compress many hours into a single frame while gathering lots of unnoticeable light. On the less extreme side, we could do a long exposure of 30 seconds, which is typical for Milky Way shots, to gather enough light to expose the Milky Way but not show much motion. The figure below is a good example of how exposure time affects the star trails in your photo. Just remember, short exposures, short trails, and long exposures, long trails.
I hope this post has been a useful introduction to astrophotography and hasn’t bored you to death. Feel free to ask questions and let me know what you’d like more details on for a future post. Also, for a more detailed post about how I captured the ‘Milky Way over Palouse Falls’ photo, check out the how to post for compositing images!