Master Astrophotography

Whether you’re a newbie to astrophotography or you’ve been doing it for ages, these tips are sure to up your photography game.

Want to learn the art of capturing an awesome meteor shower, the next supermoon, or the Milky Way galaxy across the night sky? This guide with just about everything you’ll want to know about the wonderful world of astrophotography should help! We’ve gathered tips from the pros, optimal camera settings, and some breathtaking examples to educate and inspire you to look up at the sky and get started.

What is Astrophotography?

Ryan Hutton @ryan_hutton_

Astronomy is a popular hobby in its own right. Perhaps you own a telescope, or you participate in local star club events on dark evenings. If you haven’t, these are great ways to get a feel for what astronomy is all about. There are, quite literally, a universe of possibilities out there.

Many astrophotographers start with a basic telescope and a desire to share what they find so captivating when they look through the eyepiece. Others have seen beautiful night landscape images online and in magazines and want to try their hand at taking their night photography to a new level.

To put it simply, astrophotography is the art of shooting astronomical or celestial objects. Subjects range from merely using the night sky to make landscape pictures pop to taking super sharp and close up images of distant galaxies.

First things first, budding astrophotographers need to know that planning, patience, and persistence are the name of the game. Obstacles, from bad weather and bad timing to landslides and equipment failures, can all make it a very frustrating pursuit. But in the end, despite all the obstacles, when you finally do nail the shot, astrophotography becomes one of the most rewarding forms of photography there is.

Equipment needed

While it’s tempting to try astrophotography without having to invest in any gear, astrophotography will still require some technical considerations. As a beginner, it probably makes more sense to buy or borrow an astrophotography camera. Equipment-wise, all you need is a modern DSLR camera with good low light capabilities, a fast lens, and a good sturdy tripod. and you will be able to create beautiful images of the night sky. This equipment can easily be used for all different types of photography so that it won’t feel like such a specific investment into astrophotography. It’s also crucial that you buy a proffesional tripod along with your astrophotography camera and wide-angle lens, as this will help prevent your photos from coming out blurry. A wide angle lens might be the best choice (10mm, 12mm, or 24mm) but you can use a longer lens depending on how much of the Milky Way and the surrounding scene you want to capture. Remember: A longer focal length will create star trails in only a few seconds instead of keeping the stars focused in the photo. 
When shooting the stars, you want a lens with a large aperture to allow as much light as possible through the lens. Ideally, a maximum aperture of at least f/2.8 is best, but you could still get good results with an f/4.0 lens. Unfortunately, the larger the aperture, the more expensive the lens.

Beyond that, you can also add additional accessories to your kit that will allow you to do a little more, like an intervalometer, which will allow you to do time-lapses and star trails. Of course, you can go out and accumulate a whole lot of other specialized equipment, like equatorial mount, which follow the rotation of the night sky, and robotic camera mounts for capturing large panoramic images, but for now, we’ll concentrate on the basics.

You don’t need that much gear @jakobowens

Let’s start with the basics

There are some general best practices and camera settings that apply to many types of astrophotography, including those shooting the night sky with a basic camera and lens.
You can treat this rules as a base and modify them in accordance with your camera.

  • Use manual or bulb mode
  • Use a “fast” aperture of F/2.0 – F/4
  • Set your exposure length to 15-30-seconds
  • Shoot in RAW
  • Use Manual Focus
  • Use an ISO of 400-1600 (or more)
  • Use the 10-second delay drive mode

Taking your first shot

If you’ve purchased a DSLR camera and a tripod, you’re are ready to get started. To start, have a look at the weather forecast for this week.

If the weather is clear, or mostly clear, you’re in luck.

Next, have a look at the current moon phase using our app Phototime. Nights surrounding the New Moon phase are best, where the effects of the bright moonlight are minimal. The moon washes out the fainter stars and deep-sky objects in the night sky.

For many types of astrophotography, the night of the full moon is the worst night to shoot on.

Whether you choose to travel to an interesting location or shoot from your backyard is up to you. It might be best to practice these techniques at home before venturing out to a new location in the dark.

Making sure your tripod is locked securely, aim your camera towards the brightest star in the night sky. The stars you see will, of course, depend on the time of year you are shooting. If you do not see any bright stars, angle the camera towards a distant streetlight or another distinguishable light source.

You will use a bright star to focus the camera lens.

Make sure your camera is set to Manual mode, and that your lens to manual focus. This will give you full control of the light you let into the camera.

Turn on the live-view function of your DSLR, and have a look at the screen. Depending on your current settings and brightness of your location, you may see several stars and your surroundings, or nothing at all. There are a few things you can do to see more light on the screen, including lowering the F-stop (Aperture) or bumping up the ISO (sensitivity to light).

These general settings work well at night:

@nathananderson

Astrophotography Camera Settings

Focal Length: 18mm
Focus: Manual
White Balance: Auto
Aperture: f/4
ISO: 1600
Exposure Length: 25 Seconds

 You can adjust these settings according to the DSLR camera and lens you are using. For instance, some lenses can let light in much faster with a wider aperture of F/2.8 or below.

How to determine exposure time


There are two main factors that control your exposure in photography. One of them is the time your shutter is open—shutter speed—and the other is aperture. The combination of these two determines how much light hits your sensor for giving you the final image. In astrophotography, you will be dealing with long exposures as you are photographing objects in the dark.

Shutter speed

Shutter speed is the amount of time your camera shutter is open to allow light onto the sensor. In astrophotography, we need a long shutter speed. We also have to consider that the longer you leave the shutter open, the more star trails or streaking of stars you are going to get due to the earth’s rotation. Generally, you want to avoid them in your wide field astro photos, so it’s important to know how long you can expose for before you get star trails.

This will vary depending on what focal length lens you use. The longer the focal length, the shorter the exposure time will have to be before getting star trails. Thankfully there is a formula for this called the 600 rule. This rule is simply 600 divided by the true focal length of the lens you are using. And by true focal length, it’s the focal length of the actual lens only if you are using a full-frame camera. If you are using a camera that has a smaller sensor, you need to factor the crop factor into the focal length. For example, if you were using the Canon 7d, which has a crop factor of 1.6 with a 10mm lens, then your true focal length would be 10 x 1.6, which is equivalent to a 16mm field of view on a full-frame camera.

Now, since you’ve grasped the crop factor concept, let’s go back to our 600 rule. So on a full framed camera, the maximum shutter speed you could use before seeing star trails when using, say, a 24mm lens is: 600 divided by 24mm = 25-second exposure. If you were using that same lens on a smaller sensor with a crop factor of 1.6, your maximum shutter speed would be: 6 00 divided by (24mm x 1.6) = 15.625 seconds.

Aperture

Aperture is the diaphragm mechanism of your lens, which controls how much light gets through to the sensor in the camera by opening and closing. You can think of it as the same way the pupil of your eye works—the pupil gets wider in the dark, allowing more light through your eye, but narrower when there is a lot of light, to allow in less.

We define aperture as stops, and the setting you will change to control your aperture on your camera are f-numbers. In astrophotography, we need as much light to pass through the lens and hit the sensor as possible, so we generally shoot wide open, or at your lens maximum aperture. Shooting something brighter, like the moon, would call for something like f/9 in order to really develop surface details.

ISO for astrophotography

Modern DSLR cameras are capable of high ISOs, which is great for astrophotography, as by setting a high ISO, your camera is able to pick up more detail than the naked eye can see. An ISO in digital photography measures the sensitivity of your image sensor in your camera. The higher the ISO value, the more sensitive or amplified your image sensor is to light. The only downfall is that the higher the ISO, the more noise you get in your image, but this can be rectified to a certain degree with noise reduction in post. And since we are shooting in darkness, we want to be able to shoot at the highest ISO possible without getting too much noise in the image that we will not be able to control with noise reduction. For example, on a Canon 5D MkIII, this is between an ISO of 3200 and 6400. For other cameras, this may vary, and you might not be able to push your ISO so far, but it’s worth experimenting to see just how far you can push your ISO without too much image degradation.

Preventing shake

With any form of astrophotography you will be reuired to use long exposures shots. For best results, you need to eliminate any camera movement or vibration – therefore place your camera on a sturdy tripod. But this preents only one type of vibration when using your camera.

Simply pressing the shutter button can cause camera shake. You probably won’t notice it in most pictures, but if you are trying to photograph the moon with a telephoto lens, even the slightest vibrations will be a big problem. The best way to resolve this is to either use a shutter release cable or set the self-timer on the camera. If your camera can be connected to an app – you can also release the shutter with your phone.

Another cause of vibration that is present in DSLR cameras is the vibration that the mirror causes as it is rotated up out of the way of the sensor when the shutter button is pressed. Thankfully, most cameras these days have a mirror lock mechanism so the first press of the shutter button locks the mirror up, and then a second press fires the shutter while the mirror is locked up in place.

Of cours the latter one doesn’t apply to the mirrorless cameras.

Planning – location and weather

Astrophotography can be almost impossible to do somewhere near the city due to light pollution. In order to get truly stunning shots, you might want to head out of the city and find a more secluded spot. There are a number of apps and services that can help you track down a great location, or simply grab your camera and set off on an adventure.

Know where the stars are

Part of planning for astrophotography is knowing where the part of the sky is that you want to shoot, and how it lines up with your planned composition. The night sky is constantly moving, with the position of the stars and the Milky Way constantly changing throughout the year. So, it’s important that you know where it’s going to be when you are heading out to photograph it. There are a few apps for your smartphone to help with this planning, such as Starwalk.

Account for the weather

Is it really a plan if you don’t account for the weather? The last thing you want is unexpected rain or cloud cover blocking your shot, so make sure you prepare. Check the weather in our app to be sure that the clouds will not destroy your plan.

Time-lapse astrophotography

This is just an extension of wide field astrophotography. The only difference is that you take lots of exposures over time, and then combine the frames to make a time-lapse video. The same technique can be used to make a star trail image.

Astrophotography post-processing

Software like Photoshop, Lightroom, and Aperture give you a lot of freedom with your processing techniques, especially when you are shooting RAW.

This is great for astrophotography, as it can give you a lot of control over your image, but it can also be a double-edged sword. To the untrained eye, an over-processed shot might go unnoticed, but it is important when producing good quality astro photos that you keep your processing in check. Don’t crush those blacks!

Processing is very personal, and the style of your processed image will vary from one person to another. A great way to discover your own personal style is to see how the pros do it, and use that as a jumping-off point for your own experimentation.

Be sure to check out our astrophotography presets and then start playing with them to create your own style.

Summary

Night sky photography isn’t for any type of photographer. You’ve got to enjoy spending time in the wilderness. More often than not, it involves a lot of travel and quite a bit of planning. But for those who love looking to the stars, astronomy, and photography it can be the most rewarding way to blend their passion with their proffesion.

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