Galaxy Imaging 101: Capture the Cosmos Like a Pro

Galaxy imaging is a form of astrophotography that continues to capture the imaginations of both professional astronomers and amateur stargazers alike. There’s something truly magical about capturing your own images of the cosmos, revealing a glittering world far beyond our reach.

This isn’t just about taking pictures; it’s about becoming part of a centuries-old tradition of humans striving to understand our place in the universe. Galaxy imaging allows us to bring far-off galaxies from the cold void of space directly into our homes, transforming them into personal pieces of celestial art.

However, as beguiling as it might be, galaxy imaging isn’t without its challenges. It requires a deep understanding of celestial bodies, the right equipment, and a grasp of specific techniques. But don’t be daunted. Our aim in this guide is to navigate you through the journey of galaxy imaging, equipping you with the knowledge you need to start capturing the cosmos.

So, whether you’re a seasoned stargazer looking to take your night sky observations to a new level, or a complete beginner fascinated by the allure of distant galaxies, this guide has something for you.

Understanding the Basics of Galaxy Imaging

Galaxy imaging is a specialized branch of astrophotography that focuses on capturing distant galaxies. Unlike snapping a quick shot of the Moon or a nearby planet, galaxies present a unique set of challenges due to their extreme distance and often faint appearance. But with the right knowledge and equipment, you can successfully capture these breathtaking celestial structures.

A Sky Full of Galaxies

There are an estimated two trillion galaxies in the universe, each one a vast collection of stars, gas, dust, and dark matter. Some, like our Milky Way, are spiral galaxies with sweeping arms of stars and gas. Others, like the elliptical M87, are more uniform in appearance. The variety and sheer number of galaxies make them a fascinating focus for astrophotographers.

Equipment and Software: The Tools of the Trade

To start your journey into galaxy imaging, you’ll need a few essential pieces of equipment. A telescope capable of deep-sky viewing is a must, as is a mount that can accurately track the motion of the stars. A dedicated astrophotography camera or a modified DSLR camera will capture the light from these distant objects.

In addition to the physical equipment, you’ll also need software to help you plan your imaging sessions and process your photos. Planetarium software can help you identify which galaxies are currently visible in your sky, and image processing software will allow you to enhance the details in your photos.

Understanding the basics of galaxy imaging is the first step on your journey to capturing the cosmos. In the following sections, we’ll dive deeper into the specifics of the gear you’ll need, beginner-friendly targets, and techniques to help you master galaxy imaging.

Setting up for Success: Essential Galaxy Imaging Gear

Now that we’ve introduced the basics of galaxy imaging, it’s time to dive into the specifics of the gear you’ll need. The right equipment can make a significant difference in the quality of your images, so it’s worth investing some time in understanding your options.

The Telescope: Your Eye on the Universe

When it comes to galaxy imaging, not all telescopes are created equal. You’ll want a telescope with a high light-gathering capacity, often indicated by its aperture size. Larger aperture telescopes can gather more light, which is essential for viewing and photographing distant galaxies.

Reflecting telescopes, particularly those with a Newtonian or Dobsonian design, are often favored for galaxy imaging. These types of telescopes provide a good balance between aperture size and affordability.

Check out our in-depth comparison of reflectors and refractors.

Mount: Keeping Your Targets in Sight

An often-overlooked but crucial component of galaxy imaging is the mount. The Earth’s rotation means that the stars (and galaxies) appear to move across the sky. To capture clear images, you’ll need a mount that can accurately track this motion.

Equatorial mounts are typically preferred for galaxy imaging. These mounts rotate in alignment with the Earth’s axis, allowing your telescope to smoothly track the motion of your target galaxy across the sky.

The Camera: Capturing the Light

Astrophotography requires a camera capable of long exposures to capture as much light as possible from your target galaxy. While some astrophotographers use modified DSLR cameras, others prefer dedicated astronomy cameras. These specialized cameras often have cooled sensors, which reduce noise and provide clearer images.

Software: Planning and Processing

Finally, you’ll need software to help you plan your imaging sessions and process your images. Planetarium software can help you find your target galaxies and plan when to image them, while image processing software allows you to enhance the faint details in your galaxy images.

Armed with an understanding of the essential gear for galaxy imaging, you’ll be well-prepared to begin your journey into capturing the cosmos. In the next section, we’ll introduce some beginner-friendly targets and how to find them.

Galaxy Imaging Targets for Beginners

As a budding galaxy imager, the night sky might seem like a vast ocean full of countless, unreachable islands. But don’t worry! There are plenty of galaxies out there that make for great starting points on your celestial journey. Let’s explore some of the most beginner-friendly targets that are not only easy to locate but also offer stunning views.

The Andromeda Galaxy (M31): A Spiral Beauty

First on our list is the Andromeda Galaxy, also known as M31. As our closest spiral galaxy neighbor, Andromeda is an excellent choice for your first galaxy imaging target. It’s size and relative brightness make it easier to spot than some other galaxies. Look for Andromeda in its namesake constellation during late summer and throughout winter.

galaxy imaging: andromeda
Equipment used in this stunning picture of Andromeda by Astrophoto Andy on Flikr.

William Optics ZenithStar 61ii Doublet Refractor @ 360mm FL
William Optics Adjustable Field Flattener 61A for Z61
Camera: ZWO 294mm Pro (mono)
Filter Wheel: ZWO 8 position, .36″ filters
– L (Baader Planetarium LRGB 36 mm Round CCD Filter )
– R (Baader Planetarium LRGB 36 mm Round CCD Filter )
– G (Baader Planetarium LRGB 36 mm Round CCD Filter )
– B (Baader Planetarium LRGB 36 mm Round CCD Filter )
– Losmandy GM811

Triangulum Galaxy (M33): A Local Group Gem

Next up is the Triangulum Galaxy, or Messier 33. This galaxy, while not as bright as Andromeda, is large and relatively close, making it another good choice for beginners. The Triangulum Galaxy resides in the constellation of Triangulum and is best viewed during the fall and winter months.

galaxy imaging: triangulum m33
Triangulum Galaxy in RGB & Ha by Astrophoto Andy on Flikr.

3.5 hours of Luminance
20 minutes each of RGB
3 Hours of Ha
ZWO 294mm camera
GSO f/4 Newtonian
ASI Air Plus to capture
Bortle 7 Skies

Bode’s Galaxy (M81) and Cigar Galaxy (M82): A Dynamic Duo

The Bode’s Galaxy and the Cigar Galaxy make for a fantastic pair in the night sky. Located in the constellation Ursa Major, these two galaxies are close enough to each other that you can capture them both in one shot. The Bode’s Galaxy, M81, boasts a beautiful spiral structure, while the Cigar Galaxy, M82, features an intriguing elongated shape. They’re typically easiest to spot during spring.

galaxy imaging: m81 and m82.
Bode’s Galaxy (M 81) and Cigar Galaxy (M 82) by Astrophoto Andy on Flikr.

Imaging telescope: GSO Newtonian 150/610 mm HPS Newtonian
Imaging camera: ZWO Optical ASI533MC Pro
Mount: Equatorial Losmandy GM8
Guiding telescope: QHYCCD Refractor 30/130 mm QHY MINI GUIDE SCOPE
Guiding camera: QHYCCD QHY 5L-II
Filters: Optolong Light pollution L-Pro Filter 2.00″ 90%
Accessories: Coma corrector Explore Scientific 2.00″

Pinwheel Galaxy (M101): A Whirl of Stars

Last but not least, we have the Pinwheel Galaxy or M101. This galaxy, residing in the constellation Ursa Major, is a face-on spiral galaxy. This orientation allows you to clearly see its beautiful spiral structure, making for a truly captivating image. The best time to view the Pinwheel Galaxy is during the spring.

Remember, like any skill, galaxy imaging takes time and patience to master. Don’t get discouraged if your early attempts don’t turn out exactly as you hoped. Every night under the stars brings you one step closer to capturing the cosmos. Next, we’ll dive into some techniques and tips to help you along your galaxy imaging journey.

galaxy imaging: pinwheel
M101 – The Pinwheel Galaxy by Astrophoto Andy on Flikr.

Three hours each of RGB filters and 10 hours of Luminance.
ES 127mm Refractor
ASI 294mm Pro
Losmandy G811G mount
NINA for capture
Processed in PixInsight

Mastering the Art of Galaxy Imaging: Techniques and Tips

Just like any other form of photography, galaxy imaging is an art that you can hone with practice, patience, and a few helpful tips and techniques. Here are some key points to keep in mind as you embark on your cosmic photography journey.

Know Your Equipment

Familiarize yourself with your equipment inside and out. Learn the ins and outs of your telescope, camera, and mount. Practice setting up and breaking down your equipment during the day, so you can do it efficiently in the dark.

Plan Your Galaxy Imaging Session

Planning is essential in galaxy imaging. Use planetarium software or apps to determine which galaxies will be visible on a given night, and at what time they’ll be in the best position for imaging.

Capture Multiple Exposures

Galaxies are extremely faint, so you’ll need to capture as much light as possible to bring out their details. To do this, you’ll want to capture multiple long-exposure images, also known as “subs,” of your target. You can then “stack” these images using software to increase the signal-to-noise ratio, thereby enhancing the details of the galaxy.

Use Dark and Flat Frames

In addition to your light frames, you should also capture dark and flat frames. Dark frames help to remove sensor noise, while flat frames correct for uneven field illumination. These frames can significantly improve the quality of your final image.

Also see our post on bias frames.

Practice Post-Processing

Post-processing is where your galaxy images will truly come to life. Learn to use software like PixInsight or DeepSkyStacker to stack your images and bring out the faint details of your target galaxy. Post-processing is a skill in its own right, so don’t be discouraged if it takes time to learn.

Remember, the journey is just as important as the destination in galaxy imaging. Each session brings new opportunities to learn and improve. Next, we’ll discuss how to process your galaxy images to bring out the best in them.

Processing Your Galaxy Images

Once you’ve captured your images, the work isn’t over yet. Post-processing is a crucial step in astrophotography and especially in galaxy imaging. This is where you’ll take your multiple exposures and turn them into a single, stunning image.

Stacking Your Images

Stacking is the process of aligning and combining your multiple exposures to increase the signal-to-noise ratio. This means you’ll bring out the details of the galaxy while reducing the background noise. There are several software options available for stacking, including DeepSkyStacker and PixInsight.

Adjusting Histograms and Curves

Once your images are stacked, you’ll use the histogram and curves functions to adjust the brightness, contrast, and color balance. This will help bring out the details and colors in your galaxy.

Noise Reduction

Despite your best efforts during image capture and stacking, there will likely still be some noise in your image. Most image processing software offers tools for reducing noise while preserving the details of your image.

Final Touches

Lastly, you’ll want to make any final adjustments to your image. This might include cropping the image, further adjusting the colors, or applying a sharpening filter to enhance the details.

Post-processing can be just as challenging and rewarding as capturing images. With patience and practice, you’ll learn to bring out the best in your galaxy images.

Galaxy Imaging Conclusion

Embarking on the journey of galaxy imaging is no small feat, but the rewards are truly out of this world. With this guide, you’re now equipped with the knowledge and tips to start capturing the cosmos. Remember, every master was once a beginner. So, set up your gear, aim for the stars, and most importantly, enjoy the journey!


What is the best time of year for galaxy imaging?

The best time of year for galaxy imaging largely depends on the specific galaxies you want to image. However, many galaxies are well placed for imaging during the spring months.

Do I need a special camera for galaxy imaging?

While a DSLR camera can be used for galaxy imaging, a dedicated astronomy camera will typically yield better results. These cameras are designed for long exposures and often have cooled sensors, which can reduce noise.

What is a good beginner telescope for galaxy imaging?

A Newtonian or Dobsonian telescope with a large aperture is often recommended for beginners in galaxy imaging. These telescopes provide a good balance between light-gathering capacity and affordability, but here are some specific suggestions:

  • Celestron 11-inch Rowe-Ackermann Schmidt Astrograph: This is a catadioptric telescope with an 11-inch (279mm) aperture and a 620mm focal length. It has a fast focal ratio of f/2.2 and a wide field of view that makes it ideal for capturing large and faint galaxies. It also has a built-in fan and dew shield to prevent condensation and improve image quality. It comes with a Losmandy-style dovetail rail that fits most equatorial mounts.
  • Sky-Watcher Evostar 120 EQ5 Pro: This is a refractor telescope with a 4.7-inch (120mm) aperture and a 900mm focal length. It has a moderate focal ratio of f/7.5 and an apochromatic design that reduces chromatic aberration and enhances contrast. It also has a dual-speed Crayford focuser and a 2-inch diagonal that allow for precise focusing and comfortable viewing. It comes with an equatorial GoTo mount that can automatically locate and track over 42,000 objects in the sky.
  • Explore Scientific ED127 apo refractor: This is a refractor telescope with a 5-inch (127mm) aperture and a 952mm focal length. It has a moderate focal ratio of f/7.5 and an apochromatic design that reduces chromatic aberration and enhances contrast. It also has a dual-speed Crayford focuser and a 2-inch diagonal that allow for precise focusing and comfortable viewing. It comes with a Vixen-style dovetail rail that fits most equatorial mounts.

How do I find galaxies to image?

Planetarium software can help you plan your imaging sessions and find galaxy targets. These programs show you what the night sky will look like at any given time and location, and can indicate when and where your target galaxies will be visible. Look out for our regular posts on the best targets depending on the time of year.

What is stacking in galaxy imaging?

Stacking is the process of combining multiple exposures to increase the signal-to-noise ratio in your images. This can help bring out the details of the galaxy while reducing background noise.