Getting Started with Astrophotography
Astrophotographs are among the most beautiful images around. They are full of mystery, colour, and objects that inspire us with their beauty, and their complexity.
Getting started with astrophotography requires only a camera and your imagination.
However, you will soon find that your images could be better, with some extra equipment, some post processing, some new skills. And, depending on your enthusiasm, your budget, and the time you can devote to it, could lead you down a path to creating amazing images, and definitely collecting a lot of pieces of really cool kit.
In this post I'm going to get you started with photographing the Milky Way. There is a lot more to it than this, and many more options for subjects to photograph.
I am an amateur astronomer who takes a few pictures. I am a raw beginner when it comes to making great astrophotography images, but I have been doing astronomy and photography as a hobby for over 25 years. So what you will learn in this blog post are the very first steps, and the tips I have learned over the years.
My start with astrophotography began with a lot of failure. Then I went on a short Canon workshop and learned everything I needed to know to take me from failure to: "Wow, I can actually do this." The image above is one that I took on this workshop.
Let me start with these three pieces of advice:
- Be happy with the images you end up with.
- Don’t compare your work to the work of professionals.
- Make a better image next time.
If you are just starting out you’ll make rubbish images. Really, lots of images that you will want to throw away. But anything worth doing is worth doing badly at first. Examine what you do, learn from it, and do better. Every great astrophotographer started out that way.
I've sprinkled some of my images through this post. They aren't brilliant, but I'm amazed that I can make them at all.
I'll start with some basic tips for your first attempts at astrophotography. These aren’t the only ways to do things, and there is plenty of great advice out there on the Internet. I’ve linked to a few of the best at the bottom.
As I said, I've been doing astronomy and photography for decades. Even I had thought that astrophotography was far to technical for me to get close to. I was wrong about that, but I have no doubt that my experience with both these hobbies helped me to get going quickly. So let me share some of the things I knew before I went into this so that you can get a head start too.
In this discussion I'm talking mostly about photographing the Milky Way. These are often called landscape astrophotography. There is a lot of scope too make amazing images, and you don't need a telescope. Most of the concepts apply to using a telescope as well.
You can’t do photography without a camera. I have 7 cameras. 1x iPhone, 1x iPad, 2x DSLR (one old and one newer), 1x Point and shoot, one on my laptop and a USB webcam. I could do astrophotography with any of these. My newer DSLR will give me the best results, but getting started with any of the other cameras is easy.
There are plenty of photography processing software around, and some is even free. I use Adobe Lightroom and Photoshop. Lightroom has a great iPhone app that lets me do a lot of work without my laptop.
'll do some reviews of software at another time. Here is a good list of free processing software.
Whatever software you use there are some basics you'll need to learn. I'll take you through these in the processing section later. But there is a lot more you can do than the basics.
Every piece of software has a learning curve. You’ll benefit from understanding how it works, so take your time. There are plenty of experts and tutorials out there. I’ll talk about processing in general later, so check out how you do these functions in your software.
Understanding some terminology and concepts in photography will help you make better images.
How a digital camera works: Light is reflected of any object you are looking at, this light passes from the object, through the lens in your camera onto an electronic device that senses the light and turns it into data. These data are recorded in your camera.
It’s just like your eye, which instead of electronic your retina is biological. It senses light and turns it into neural impulses to be recorded in your brain.
Lenses: In order to create a coherent picture out of the light coming from objects the light needs to be focused. The camera lens focuses the light onto the sensor.
You see the world because your eye lens focuses the light on your retina. For those of us with less good vision, our glasses or contact lenses make adjustments to the incoming light to compensate for the inadequacies of our own eye lens.
Lenses also magnify your subject, making it look closer, or widen the view with a wide angle lens. Here is an example of a very wide angle and can do other functions such as fisheye to get a very wide of the scene in front of you. Here us an example of very wide angle astrophotography.
Aperture: This is the opening that allows the light in onto the sensor. This is usually a function of your lens. The wider the aperture, the more light comes in. This is important in astrophotography when you are dealing with very low light. This is referred to as a f number and the lower the number the wider the opening.
Its also the same with your eye. Your pupil will dilate (create a bigger opening) in low light conditions to let more light through to your retina.
Shutter speed: Your camera sensor will collect light for as long as it is exposed to light. The more light it collects, the more detail you will have on your image. The camera shutter speed is how long the sensor is open to light, and how long it should collect light data for.
ISO: The ISO is a technical reference to how sensitive your camera sensor is. You might think that a more sensitive sensor will make a better image, but it isn’t that simple. Greater sensitivity also creates more digital noise in your camera sensor. So there is a balance to find – enough sensitivity to capture a great image, and not too much to generate noise. Good cameras will have better performance at higher ISO.
White Balance: This relates to how your camera perceives the wavelengths of light as it records them. You’ve probably taken pictures at night and said: “It didn’t look like that”. This is because your eyes (actually your brain) make an adjustment for the general colour of the light in the scene you are looking at. Your camera may have an automatic white balance, which means it will adjust when it is in a room lit by fluorescent light differently to a sunlit scene. For astrophotography it is better to be sure and set it yourself.
File Format: If your camera can shoot in RAW, and you have processing software that will open RAW then you should shoot astrophotography in RAW. If not, you will be shooting and processing in JPG. The bigger the file the more you will be able to do with it. So if your camera has options for the size of the file it records, select the largest file size. Remember that bigger file sizes will fill up your storage space more quickly.
When you are photographing the sky there are a few things to remember. These things will affect the outcome of your image. Understanding them will improve your images.
Long exposures need stability
You will be taking long exposures, whether that is using an app like Nightcap or Manual, or even Lighroom camera to control your mobile phone camera, or using a DSLR, the longer the exposure you can take, the more starlight you will have to work with. But you can’t take anything useful with a long exposure unless you stabilise your camera. If you don’t have a tripod to support your camera, here are some ideas:
Lay it on a flat surface, with the camera lens pointing up. Remember you can set the camera to timer so that you can set it off and position it flat. You can also take images with the side buttons, but be careful not to move your phone.
Fold paper into wedges and stabilise with tape to get different angles.
Use tape to stick it to something stable, such as a post or a wall. You may need some paper wedges to make this work too. I use tape to with my iPhone and tripod.
It’s possible without a tripod, but easier with one.
The Sky Moves*
Even a perfectly placed solid tripod won’t move with the sky. You’ll need to account for the movement of the sky during your exposure. The wider your angle, and the wider your aperture, the longer your exposure can be.
There is a calculation which I’ve included below when I talk about exposure.
You might also want to photograph star trails. This is a specific type of astrophotography and can be beautiful. Timelapse techniques take advantage of the sky moving and can look amazing. There is a stunning example from Mark Gee below.
*Technically, it's the Earth that is moving. But we perceive it as the sky moving.
Objects are small
The moon is the largest single object you will be imaging. It is 0.5 degrees in size (sky sizes are measured in degrees which are part of a circle. There are 360 degrees around the entire horizon). Through a camera lens, the Moon is tiny.
Telescopes are just big lenses. With a good telephoto lens you can take images of the moon and some other large objects such as Andromeda, and constellations, but you'll need a very big lens to capture those lovely cloudy images of the Orion Nebula and Pleades.
You can use binoculars to capture the moon and bright sky objects, even with a mobile phone. Make sure they are fixed to a tripod and use manual settings to get the best exposure.
That doesn’t mean that astrophotography is out of reach. Some of the best images are of the Milky Way. This surrounds us, and the opportunities to make amazing images of it are endless. Many professional astrophotographers capture only the Milky Way.
If you are in the right latitudes, that is far enough North or South, Aurora are also amazing subjects. I don’t see them from where I am, but I have seen them and wish I had known how to take images of them.
The Milky Way and Aurora are great subjects for mobile phones, small cameras and wide angle lenses.
Remember that all the skills you learn in creating amazing photographs of the Milky Way will give you a head start when you can get access to equipment that takes you deeper into the sky.
Whatever your camera equipment, your images are going to be disappointing if you don’t get the focus right. You can’t fix focus in processing.
I wear multi-focal glasses and focus is a bit tricky with those. I don’t wear them when I am viewing through my telescope. Instead I focus for my eyes. But focusing with a camera has to be just right.
For most phone and tablet devices you simply touch the screen on the object you want to focus on. When the sky is dark this can be a bit of a problem.
You’ll need to understand how your camera works to focus, and if you can focus manually, or focus automatically and lock the focus. This is also the case with exposures. Setting manual exposures will get you the best results.
Focus on a star using a DSLR Screen
Do this on your tripod if you can because it’s tricky to hold the camera steady and do things on the screen at the same time
Your camera will now be focused on the stars. Try not to bump it out of focus.
The Sky is bright
There is a lot more light in the sky than your eyes perceive. Your camera sensor is a lot better at collecting light, so expect to be surprised, and disappointed by what you see.
When you process your images you’ll see shapes and structures in your the Milky Way that you didn’t know where there. This is one of the surprising things about astrophotography, you can find all kinds of exciting shapes and colours in your images that you could not see with your eyes.
You’ll also discover that the sky is full of light that does not come from the stars. Finding a dark sky is difficult when you live near population centres.
You’ll discover that your images are filled with upspilled light, glows of towns on the horizon and light reflecting off haze, smoke, or seaspray in the air. We can manage this through processing and you can still take great images. When you get out into a dark sky you will be ready to take those really special shots.
3 Steps to a Great Photo
Time to get down to the business of taking an image. You’ve done the theory. Here is the practice.
Firstly – start slowly. Practice. Try out different settings. See what works with your equipment and your software. Learn by trial and error.
Secondly – Share your images, even if you think they are terrible. In a good community you’ll get feedback from people to help you improve your images.
Practice makes perfect, and feedback helps.
The three steps to a great photo:
- Plan – Object, Time, location, equipment, exposures
- Image – setup, focus, image, review, redo.
- Process – Exposure, contrast, colours,
STEP 1 Plan
Making a plan is always the first step to success. You want to be spending your time taking images of the sky, not fussing with equipment, or figuring out exposures. The more images you are able to take, the more likely you are of getting something you are excited about. Here are some places to start for your plan:
What are you going to take an image of? Is it the sky at night from your backyard? Or are you planning something more spectacular? This is where you get to be creative. Reproduce an image that you have seen, or thing of a place nearby that will have a skyscape that will inspire your creativity.
When will you take the image? Do you need to be ready on a special day and time, for example for a meteor shower, or a conjunction?
Where will you take your images from? Can you get to a darker site, or are you just practicing so from your suburb is OK?
What gear will you need? Create a checklist to ensure that you take everything with you. If you ever forget something, add it to your checklist. I say this from experience. Here are some things your checklist might include:
- Your Plan
- Charged batteries
- Battery backup
- Space on memory card, or a spare card
- Red light (for reading and not messing with your night vision)
- Warm clothes
What shots will you take? How many exposures will you need? Do you need props or tools for light painting (brightening part of the landscape to get it exposed in the shot)? What shots at different exposures will you take? How much are you experimenting? What will be a perfect shot for the night?
You’ll get better at planning as you learn what works and what doesn’t with your equipment. Remember that it is easy to take shots with a digital camera, and the more options you give yourself in processing, the better your chances of a good shot.
Basic Settings for DSLR Landscape Astrophotography
Most good cameras can accommodate these settings. Some mobile phone apps will do a better job than the standard camera. Learn what your equipment can do and work with it.
Calculate your Maximum Shutter Speed
500 / (lens focal length x crop factor)
This will give you the maximum shutter speed in seconds before star trails will appear in your image.
If you’ve got this far in the blog post you won’t be just pointing and clicking, you are prepared to work for a good image. Getting the exposure right is much easier if you have this starting point.
The exposure guide above will give you the basic settings for your camera. All of these assume that you can set them manually in your camera.
The maximum shutter speed is dependent on your lens, and your camera sensor. If your shutter is open too long you will get star trails. This is only good if you want star trails.
If your camera is not full frame you’ll need to know the crop factor. This is the difference in scale between a full frame (same as 35mm film frame) camera sensor and the one on your camera.
For my DSLR the crop factor is 1.6. Others are 1.5. For an Iphone is it 7.21
Remember to adjust the calculation if you are using a zoom lens. If you zoom in your maximum shutter speed will be lower.
For my camera this is 17.3s. For my iPhone this is 16.6s. For my camera on my telescope it is less than a second!
With all this set up on your camera you are ready to choose your angle and view, and take your picture.
I usually do a test image, and review the settings, before working through my plan, just to make sure I have everything right. I also manage my camera, includign shutter release, from my iPhone after connecting it to the camera. This reduces the chances of wobbling the camera when I press the button.
STEP 3 Process your Image
Using the best screen you have open your image in your chosen processing app.
The software you are using can probably do a lot more than you need. I’ll give you the things to start with. Get familiar with the changes that these settings make. Play around with them. The best settings will vary with your subject, exposure, camera, the sky, and your image preferences.
If you are working with a RAW image you have control over white balance and more pixels to work with. RAW is great for astrophotography because no light is lost through compression.
This is a brief checklist of what you can do to make your image pop, whatever format you are using. The easiest way is to adjust the settings until the image looks right. Then note the settings to save time on your next image.
- If you are in RAW adjust the White Balance if you need to.
- Using the “whites”, scale it up until the stars pop out and you are happy with how it looks.
- Using the “blacks”, scale this down until the sky is dark and shapes are visible.
- I like to increase the contrast, and changing the brightness can make a difference.
- If your software has a “Clarity” option, then adjust this a little. Be careful not to add noise, you'll see this when you zoom in.
- If your sky has been very washed out using “de-haze” can also make a difference.
- Sharpen and reduce noise if these help.
There is a lot more that you can do, such as modifying a part of your image only, but this should result in a great image.
Remember that this is your image, and your creativity, and your eye. Make the image that you love to look at. Then share it with others. I have no doubt that other people will be surprised by your work.
At Our Wide Sky we love to see the images of people who are getting started with Astrophotography. Share with us on Facebook, Twitter, Instagram. I’ve love to hear about your experience with these techniques.
Below are some of the best resources I could find on the Internet. There are plenty more out there so consider this a starting point.
Sky and Telescope: Removing Light Pollution from your Astro Images
Lonely Speck: Astrophotography Tutorials
Lonely Speck: Astrophotography 101
Lonely Speck: Focusing at night
Lonely Speck: Processing Milky Way Images in Lightroom
Mark Gee: Photographing the night sky
Improve Photography: Ultimate Guide to Editing Milky Way Images
Peta Pixel: Picking a great lens for Milky Way Photography
Canon Australia: Astrophotography
Iphone Photography School: The Night Sky (lots of annoying popus, but a good resource)