M31 - The Andromeda Galaxy

Updated: Nov 22, 2020

The Andromeda Galaxy, along with M32 and M110, two dwarf galaxies orbiting M31, is by far the easiest galaxy to image for beginners! It is huge, bright, and is one of the most impressive deep sky objects in the Northern hemisphere.

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).

Scroll down for all the details as well as the Wide-Field version!

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 camera to image M31. 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 a year or two.


Camera: QHY600C

Telescope: Stellarvue SVX130

Mount: Paramount MyT

Guiding: ZWO ASI 290MM Mini

Accessories: Moonlite Nightcrawler focuser

Processing: Pixinsight


Total Exposure Time: 6.5 hours

Exposure Time per frame: 3 minutes

Filters: N/A

Gain: 26

Want to see how I imaged this object? Check out the video below! That night, I slept in the trunk of the car and imaged both M31 and M45 until sunrise.

The Andromeda Galaxy with a DSLR camera

September 11, 2016

Below is our DSLR photograph of the Andromeda Galaxy, taken with a Canon t3i and a total exposure time of 5.5 hours.

This was taken from a Bortle 4 zone and was done in two different nights. I really love how the blue colors turned out!


Camera: Canon T3i (600D)

Telescope: Orion 8" Astrograph f/3.9

Mount: Atlas EQ-G motorized Mount

Coma: Baader MPCC Coma Corrector MkIII

Guiding: Starshoot Autoguider - 50mm Guide Scope

Processing: Pixinsight


Total Exposure Time: 5.5 hours

ISO: 400

Locating the Andromeda Galaxy

Called The Great Andromeda Nebula until his galactic nature was recognized in the 1920s, the spiral Andromeda Galaxy is the closest galaxy from the Milky Way, and the largest one in our Local Group. It is believed to contain about a thousand billion stars.

The Andromeda galaxy will collide with ours in about 3.75 billion years.

The Andromeda Galaxy is one of the few galaxies visible to the naked eye from Earth in the Northern hemisphere. It is also one of the biggest objects in the night sky. 

M31 lies between the Great Pegasus Square and Cassiopeia, and the easiest way to find it is to first locate Pegasus’ square. Once you do, look for the corner closest to Cassiopeia’s “W” shape and jump to the first, then second star out of that corner. That second star should be the bright Mirach. Finally, do the same double jump, but at a 90 degree angle up this time, and you will find yourself staring at the brightest galaxy in the Messier catalog.

Note that viewing this target with binoculars or a telescope will also reveal its satellite galaxy: M110! You may also observe M32, but it will most likely not be visible as it is washed in M31’s gases.

Wide-Field capture of M31

If unsure how to approach this target, it is a good idea to simply attach your DSLR camera to a sky tracker and photograph it wide-field. The good thing about that is that you don't need to worry too much about centering the galaxy, and you can also get M33, the Triangulum Galaxy in the same frame!

The image below was taken with a simple 50mm lens attached on a Canon t3i, with exposures of 3 minutes for 4 hours. We use an iOptron Skytracker in order to be able to do 3 minutes of exposure without star trails.


Camera: Canon T3i (600D)

Lens: Canon 50mm f/1.8

Mount: iOptron Skytracker

Processing: Pixinsight


Total Exposure Time: 4 hours

ISO: 800

Single Shot & 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 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. It is not until I found an amazing processing tutorial by Light Vortex Astronomy (which you can read HERE) that I ended up with an image I loved. 

As for the wide field version, the only challenge is 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 any issue for the newer attempt at the galaxy with an OSC camera, as I am now much better at PixInsight than I was back then. If you are interested in learning how I process all our images nowadays, you can download a full PDF "follow along" file that contains 77 pages, a full 1 hour and 45 minutes walkthrough tutorial video, our custom pre-sets for your dashboard and even raw data HERE.

Comparing our shot of the Andromeda Galaxy with the first image every taken, 128 years prior

It’s been cloudy for some time now so 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 very nice looking image which 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 an 8” (reflector as well), the Orion 8” Astrograph which is a level entry, under $500 telescope. 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).

All our versions 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.

Galactic Hunter Episode #4 - The Andromeda Galaxy

The Andromeda Galaxy was the star of one of our episodes of Galactic Hunter! Here is the full episode below.

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!

Make sure to follow us on Facebook, Instagram, and YouTube to stay up to date with our work!

Clear Skies,

Antoine & Dalia Grelin

Galactic Hunter


The Astrophotographer's Guidebook

Description: Discover 60 Deep Sky Objects that will considerably improve your Imaging and Processing skills! Whether you are a beginner, intermediate, or advanced astrophotographer, this detailed book of the best deep sky objects will serve as a personal guide for years to come! Discover which star clusters, nebulae, and galaxies are the easiest and most impressive to photograph for each season. Learn how to find each object in the night sky, and read our recommendations on imaging them in a quick and comprehensive way. Each target in this guide contains our advice on imaging, photos of expected results, and a useful information table. We've also included a few cool facts about each target, a map to find it in the night sky, and more!

The Astrophotographer's Journal

Description: The Astrophotographer’s Journal is a portable notebook created for the purpose of recording observations, cataloguing photographs, and writing down the wonderful memories created by this hobby. This book contains more than 200 pages to memorialize your stargazing and imaging sessions, as well as a useful chart on the last pages to index exciting or important notes. Read back on the logs to see how much progress you have made through the months, the problems you overcame, and the notes taken to improve in the future. Just as the pioneers of astronomy did in their time, look up and take notes of your observations as you are the author of this star-filled journey.

The Constellations Handbook

Description: The Constellations Handbook is a logical guide to learning the 88 constellations. Learning the constellations is difficult. Remembering them is even harder. Have you ever wanted to look up to the night sky, name any pattern of stars and be able to tell their stories?

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