Messier 31 - The Andromeda Galaxy | Astrophotography and Tips
Updated: Jun 12
The Andromeda Galaxy is by far the easiest galaxy to image for beginner astrophotographers! It is huge, bright, and is one of the most impressive deep sky objects in the northern hemisphere. In this post, you will find information, images, and tips to photograph the Andromeda Galaxy.
Object Designation: M31
Also known as: The Andromeda Galaxy
Constellation: Andromeda
Object Type: Galaxy
Distance: 2.45 million light-years away
Magnitude: 3.44
Discovered in: 964 (first known report)
Because of its diameter of more than six times that of the Moon, we recommend imaging this target with a small to medium size telescope, as the galaxy will not fit completely in the frame if using a larger instrument (unless doing a mosaic).
We have captured the galaxy many times using both DSLR and astronomy cameras, with and without a telescope!
1,058 Hours on the Andromeda Galaxy
September 2023 - March 2024
After the 255-hour image on the Whirlpool Galaxy released in the Summer of 2023, we decided to collaborate with the Deep Sky Collective yet again to produce the most impressive and accurate picture of a deep sky object ever.
After 6 months of work, we are all very proud to share our Kilo-hour image of Messier 31.
Gear used (for our part of the data):
Camera: QHY600M + ZWO ASI2600MC
Telescope: Stellarvue SVX130 + RASA 8
Mount: 10Micron GM1000 HPS
Processing: Done by Steeve and Uri, using Pixinsight and R-C Astro plugins
More information: Be sure to visit this image's Astrobin page for much more information and to see the list of all contributors.
The Andromeda Galaxy with a cooled OSC camera
October 14, 2020
It is now time to capture the Andromeda Galaxy with a cooled astronomy camera!
I went back to a Bortle 4 zone and used the QHY600C One-Shot-Color camera to image Messier 31. I spent two half-nights on it for a total exposure time of 6.5 hours. I spent the first half of the first night on the Pleiades, which I love, and the first half of the second night imaging various small clusters.
Below is the result! I do miss the diffraction spikes that I got when imaging this target with my Newtonian reflector, so I plan on revisiting this object with a reflector in the future.
GEAR USED:
Camera: QHY600C
Telescope: Stellarvue SVX130
Mount: Paramount MyT
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nightcrawler focuser
Processing: Pixinsight, with RC-Astro plugins
ACQUISITION DETAILS:
Total Exposure Time: 6.5 hours
Exposure Time per frame: 3 minutes
Filters: N/A
Gain: 26
How to Photograph the M31 Galaxy - Video
Want to see how I took a picture of the Andromeda Galaxy? Check out the video below! That night, I slept in the trunk of the car and imaged both M31 and M45 until sunrise. You might see that the final image looks different than the one above, mostly the colors, and that is because I have reprocessed the galaxy several times since this video came out. I will talk about processing the Andromeda Galaxy later in this post!
Our First Picture of the Andromeda Galaxy with a DSLR and Telescope
September 11, 2016
In September 2016, we took our first picture of the Andromeda Galaxy with a telescope! We drove to a Bortle 4 zone in the desert about 45 minutes away from Las Vegas where we live. We attached our unmodified Canon T3i DSLR camera to our 8" Newtonian reflector telescope and aimed it at Messier 31 for a total of 5.5 hours.
Overall, I really love how the blue colors turned out as well as the orange hues near the bright core of the galaxy! I am very pleased with this image considering this is our first attempt at the Andromeda Galaxy with a telescope.
GEAR USED:
Camera: Canon T3i (600D)
Telescope: 8" Astrograph f/3.9
Mount: Equatorial Motorized Mount
Guiding: Autoguider - 50mm Guide Scope
Processing: Pixinsight
ACQUISITION DETAILS:
Total Exposure Time: 5.5 hours
ISO: 400
How to find the Andromeda Galaxy in the Sky?
The Andromeda Galaxy lies 2.537 million light-years away in the constellation Andromeda. The best time to image M31 is in the Fall, but it stays available in the sky for most of the year.
Finding the Andromeda Galaxy is simple if you are observing from a location free of light pollution, as the object will look very obvious in the sky as a bright but fuzzy patch of light.
The easiest way to spot the galaxy is to star hop from either Cassiopeia or, our favorite method, using Pegasus' square and jumping to Mirach.
The Andromeda Galaxy is visible to the naked eye if observed from a dark location, and can easily be found with binoculars or a telescope.
The Andromeda Galaxy is found between two bright constellations, Pegasus and Cassiopeia.
First, find Pegasus' square, which should be simple as it is an almost perfect square made up of four bright stars. Then, within that square, start from the star that is closest to the Cassiopeia constellation. You then simply have to star hop to the first, then second bright star (Mirach) as if you were traveling towards Cassiopeia. Lastly, make a 90-degree turn to the right and do one more double jump to land on the Andromeda Galaxy. If you are having trouble seeing it, try averted vision! This works by looking slightly to the side of the object instead of directly at it.
Andromeda Galaxy Information
With a diameter of 200,000 light-years, M31 is the largest galaxy in our Local Group. It is also the largest visible galaxy with an apparent size in the sky of six full moons!
The Andromeda Galaxy is home to approximately one trillion stars, which is more than twice as many stars as our Milky Way is estimated to have. Scientists also found a huge amount of nebulous regions and star clusters within the spiral arms of the galaxy. The Andromeda Galaxy is believed to be 10 billion years old, which is younger than the Milky Way by 3 and a half billion years.
The picture above was taken by the Hubble Space Telescope in January 2015 and shows a section of the Andromeda Galaxy in very high resolution. Go ahead, click the image, and zoom in all you want! The galaxy is so large that the image is made up of hundreds of mosaic panels, and still, the entire object still doesn't fit!
The Andromeda Galaxy is getting closer and closer to us and is expected to collide with our Milky Way in 3.75 billion years. The two galaxies will merge into one, "Milkomeda" until merging with yet another galaxy, the Triangulum Galaxy.
If you'd like to learn more, read our M31 blog post where we go over as many facts about the Andromeda Galaxy as possible.
Wide-field Astrophotography of the Andromeda Galaxy
Being so bright and large, beginner astrophotographers can easily capture M31 widefield without a telescope. If you are beginning in the hobby and are unsure about how to approach this target, it is a good idea to simply attach your DSLR camera to a tripod and photograph it wide-field. By doing this, you won't need to worry too much about centering the galaxy, and you can also get M33, the Triangulum Galaxy in the same frame!
We imaged Andromeda with and without a star tracker, see both attempts below!
Capturing the Andromeda Galaxy with a DSLR camera and Star Tracker
The image below was taken with an affordable 50mm lens attached to an old stock Canon t3i, with exposures of 3 minutes for 4 hours. We used a star tracker in order to be able to do 3 minutes of exposure without star trails.
As you can see, the Andromeda Galaxy is visible to the right, and the smaller Triangulum galaxy can be seen near the center bottom area. The colors in M31 are beautiful and look natural, but the blue hue in M33 is definitely too strong. This is because I processed this image when I was learning PixInsight and wasn't very good at it just yet! Still, the overall image is beautiful in my opinion.
GEAR USED:
Camera: Canon T3i (600D)
Lens: Canon 50mm f/1.8
Mount: iOptron Skytracker
Processing: Pixinsight
ACQUISITION DETAILS:
Total Exposure Time: 4 hours
ISO: 800
Capturing the Andromeda Galaxy with a DSLR camera and Tripod
The image below is our attempt at photographing the Andromeda Galaxy without tracking and with just a DSLR camera, a tripod, and a lens. We used the Canon T3i which is now very old, so you'll likely get a much cleaner image if you decide to try it with a more recent camera. This was shot from a Bortle 4 zone so there wasn't too much light pollution.
We took this picture when we were complete beginners back in 2015, with gear that was used and cheap. All this to say that you can also take great images of the Andromeda Galaxy without much skill and with poor equipment! So go out and try!
GEAR USED:
Camera: Canon T3i (600D)
Lens: Canon 50mm f/1.8
Processing: Pixinsight
ACQUISITION DETAILS:
Total Exposure Time: 2 hours
ISO: 1600
What exposure time should you use to photograph the Andromeda Galaxy untracked?
The exposure time you will pick needs to be perfect because, without a tracker, the stars will start to show trails very fast, especially if you use a lens with a long focal length. The problem is that you want the longest possible exposure time possible in order to get as much signal as possible.
If you are a beginner, we recommend you use the "500 Rule" to calculate how long your exposures can be before you see trails. This rule works well most of the time but is not extremely accurate depending on the camera and lens you use. It still is good for beginners. A better way to calculate the longest possible exposure time is by using the NFT rule, which we go over in Season 2 of the Galactic Course.
A 135mm lens was used as an example for the calculations below.
Using the 500 Rule if you have a cropped-sensor camera:
500 / (1.6 * Focal length of the lens) = Maximum exposure time in seconds before seeing star trails
500 / (1.6 * 135mm) = Maximum exposure time in seconds
500 / 216mm = 2.31 seconds
Rounded down: 2 seconds
Using the 500 Rule if you have a full-frame camera:
500 / Focal length of the lens = Maximum exposure time in seconds before seeing star trails
500 / 24mm = 3.70 seconds
Rounded down: 3 seconds
Note: The crop factor between an APS-C and a full-frame camera depends on the brand.
The crop factor for Canon cameras is x1.6
The crop factor for Nikon and Sony cameras is x1.5
At 135mm focal length, your exposure time for the Andromeda Galaxy should be 2 or 3 seconds. Other camera settings we recommend are an ISO of 1600-6200 (go high if your camera does well with noise) and a wide-open aperture (f/2 for the suggested lens). Note that some lenses perform better around f/4 due to vignetting and coma issues.
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Recommended Equipment for Widefield Astrophotography of the Andromeda Galaxy
If you are a beginner astrophotographer trying to figure out what you need to take your first picture of the Andromeda Galaxy, here are some affordable suggestions for your first rig.
Tripod: Orion Paragon or CF Tripod
Both of these tripods are great. We started with the Orion Paragon which is perfect for astrophotography. It is affordable but slightly bulky and heavy. The Carbon Fiber Tripod is more expensive but much more compact and lighter.
Camera: Canon t8i
The Canon TXi series is what we would pick as our first DSLR camera if we were to start astrophotography today! We started with the T3i, but go ahead and get either the latest version available or one that fits your budget.
[Optional] Do not forget to also add an intervalometer, which will allow you to take long exposure shots and add intervals. Some cameras now have built-in intervalometers.
Lens: Canon EF 50mm f/1.8 or Samyang 135mm f/2
What are the best camera lenses for photographing galaxies? The smallest focal length we would suggest is 50mm because it is great for the Andromeda Galaxy but a bit too wide for most other galaxies in the sky. If we had to pick one lens to image Messier 31, we would go with the popular Samyang 135mm f/2 which is fast and free of distortions. Besides M31, there are plenty of 135mm astrophotography targets you can capture, so it is a good investment if you plan to often image widefield
Tracker: Sky-Watcher Star Adventurer Pro
[Optional] If you want to track the sky and be able to take much longer exposures and have a cleaner image, get yourself a star tracker! These are easy to use and are like "mini-mounts" for astrophotography.
Do I need a modified DSLR camera or a filter to image the Andromeda Galaxy?
The Andromeda Galaxy does have several regions of star-forming activity rich in Hydrogen Alpha visible in the spiral arms. There is also a lot of very faint Ha gas present in the background around the galaxy.
If you are a beginner, we do not recommend bothering with a narrowband filter or modifying your camera if your main purpose is to photograph the Andromeda Galaxy. On the other hand, if you also plan to do astrophotography of emission nebulae like the Orion Nebula, the Barnard's Loop complex, or anything in Cygnus, then modifying your camera or using a filter will be worth it then.
The comparison image above shows the Orion constellation with a stock unmodified DSLR camera (left) versus a mirrorless camera modified for astrophotography (right). Click the image to learn more about modifying a camera for the purpose of imaging deep-sky objects.
But for M31 in particular, you do not require a modded camera or a narrowband filter, or rather, it is not worth the trouble. You will get a beautiful image without targeting the narrowband gases.
If you are an advanced astrophotographer, we suggest using a long focal length lens (like the excellent Samyang 135mm f/2) attached to an Astro-modified DSLR or mirrorless camera. This will let you capture the red regions in M31 and, if doing very long exposures, the hydrogen alpha gases behind the galaxy.
The image on the left was taken by Giuseppe Donatiello, and you can see the clouds of hydrogen alpha all around the Andromeda Galaxy!
Note that this might be easier to achieve using a small telescope with a cooled monochrome camera using LRGBHa filters instead of an OSC camera.
If you have a DSLR or OSC camera and are looking for a challenge, then the best filter for the Andromeda Galaxy is a Hydrogen Alpha filter. Do not bother with an SII or OIII filter. This is of course meant to capture the emission regions in the galaxy and the data will need to be stacked to your regular RGB data.
If you are looking for a light pollution filter to photograph the Andromeda galaxy from your backyard, then you will need a broadband filter. We suggest the Optolong L-Pro filter which is popular for galaxy astrophotography from the city.
Single Shot and Processing of M31
For such a huge target, the editing process can be pretty vicious, due to the lack of actual space and black around the gases of the galaxy, so do not underestimate the difficulty of processing the Andromeda Galaxy. Back then, I also did not have much experience and was still struggling to learn PixInsight.
It was a lot of trial and error, I knew I had enough data for a very good image, and all the single shots (see below) looked very promising! Still, I had to start over several times as I was not pleased with the result.
As for the wide field version, the only challenge was to get both M31 and M33 without blowing out the core of one or the other (if you decided to center your camera so that you can capture both in the same frame). Except that, it does not really present any other difficulty.
I did not have an issue with a recent attempt at the Galaxy with an OSC camera, as I am better at PixInsight than I was back then.
If you are interested in learning how I process all our images nowadays, you can access a full "follow along" guide, our custom pre-sets for your dashboard, and even raw data HERE.
The lessons are updated whenever I tweak my workflow or add more to it, so you always get the updates for free!
As I said earlier, I reprocessed the 2020 data a few times before being fully happy with the result. Below you can see how different the exact same data can look when using different processing steps. The image on the left is the result of my first processing attempt the day after capturing the galaxy. The image on the right is the same image reprocessed two years later!
This time, I did everything I could to bring out much more of the blue colors within the spiral arms of the Andromeda Galaxy. I also went with a much darker background and reduced the size of the stars further. The processing software used was PixInsight, and the final enhancements were done using Lightroom and the Topaz Suite which can be good for astrophotography if used carefully.
Which version do you prefer?
- 2020 Andromeda!
- 2022 Andromeda!
I recorded a video showing you how I processed the Andromeda Galaxy using PixInsight. For the purposes of the videos, I tried to go through each step without wasting too much time, so know that if you take your time, you will likely get an even better result!
Comparing our shot of the Andromeda Galaxy with the first image ever taken of M31, 128 years prior
I decided to put together a comparison image of two photos taken of the Andromeda Galaxy, 128 years apart.
The one on the left was taken four days after Christmas on December 29, 1888, by Isaac Roberts. This was the very first image ever taken of Messier 31, which was thought to be a nebula within our Milky Way galaxy. This was also the first time we realized M31 had a spiral structure.
The telescope he used was a 20” reflector made by Howard Grubb. To be honest, this is a great-looking image that would have definitely deserved to be APOD back in 1888!
I remembered that we took an image that had a similar framing and angle back in 2016. You can see it on the right. The telescope used was a $500 entry-level 8” reflector. The camera used was an old Canon T3i, unmodified. You can see the other acquisition details on our main image at the beginning of this post.
This comparison is fascinating. In both images, you can see two of M31’s satellite galaxies, M32 (top left) and M110 (bottom right).
Get our Raw Data on the Andromeda Galaxy!
If you are looking for high-quality astrophotography data to practice processing, you will find the dataset for this target and many more on our Raw Data page! The master files were carefully calibrated and prepared for you to open in your favorite processing software.
The Andromeda Galaxy with the Smart Telescope Vespera
In September of 2022, we decided to review the new all-in-one smart telescope from Vaonis, named Vespera.
I drove about 2 hours away from the city to reach a dark site in the desert and pointed Vespera at Messier 31.
Thanks to the clean dark sky, I didn't bother using any filter and simply told the telescope to shoot the galaxy for a couple of hours.
The result here is a total of 1.5 hours of integration time doing 10-second exposures on the Andromeda Galaxy. I processed the data on PixInsight and Lightroom.
Pictures of M31
Below are (almost) all of our attempts at capturing M31, which all lead to gains of experience and upgrading our equipment in order to end up with our first happy result of the Andromeda Galaxy, visible in the bottom right.
Andromeda Galaxy FAQ
In which constellation is the Andromeda Galaxy located?
You can find the Andromeda Galaxy in the constellation Andromeda.
How big is the Andromeda Galaxy?
M31 is the largest and brightest and largest galaxy visible in the sky. Its true size is 200,000 light-years in diameter. Its apparent size in the sky is 6 full moons.
How far is the Andromeda Galaxy?
M31 is located 2.537 million light-years away from Earth.
When was the first picture of the Andromeda Galaxy taken?
The very first picture taken of M31 was in 1888 by Isaac Roberts.
How long should my exposure time be when photographing the Andromeda Galaxy?
180 seconds (3 minutes) is a good starting point for telescopes with a focal ratio of f/5 and most cameras. If you take longer exposures, you risk blowing out the bright core of the galaxy.
Should I use a filter to image the Andromeda Galaxy?
M31 is a broadband target, so you do not need any filter. If you want to get the most out of it, you can add some data using an HA filter, as the galaxy does have several regions of star-forming activity rich in hydrogen alpha.
What equipment do I need to photograph the Andromeda Galaxy?
You can capture M31 with any DSLR or astronomy-dedicated camera, and the galaxy is easily imaged with or without a telescope. A tracking mount will help get the cleanest result. Try shooting it with whatever gear you already have first!
Is the Andromeda Galaxy a nebula?
No, it was believed to be a nebula for a very long time and was called "The Great Nebula in Andromeda" until the year 1923.
What is the Andromeda-Milky Way collision?
The Milky Way and the Andromeda Galaxy will collide in 3.75 billion years and merge into one galaxy, the Milkomeda Galaxy.
Final Thoughts
The Andromeda Galaxy is the most impressive, and best galaxy to capture for any amateur astrophotographer. M31 makes for a great image when photographed with and without a telescope as it is also a fantastic wide-field target. You will also be able to get two extra Messier objects: M32 and M110!
Have you captured Messier 31? Attach your image in the comments and let us know your acquisition details!
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