Updated: Jun 23
M101 is a large spiral galaxy that is seen face-on. While difficult to see visually, it is an easy target for beginner astrophotographers. In this post, you will find information, images, and tips to photograph the Pinwheel Galaxy.
Object Designation: M101, NGC 5457
Also known as: The Pinwheel Galaxy
Constellation: Ursa Major
Object Type: Spiral Galaxy
Distance: 20.9 million light-years away
Discovery: Pierre Méchain in1781
We have photographed the Pinwheel galaxy several times over the years with different telescopes and cameras, we'll show you each attempt below!
The Pinwheel Galaxy appears symmetrical at first, but long exposures reveal that it is obviously not. The reason for that is its dwarf companion NGC 5474, which interacts with M101 with its gravitational force.
Several other small galaxies in the surroundings of the Pinwheel are also to blame for the non-symmetrical shape of this beautiful Messier object.
M101 Astrophotography from a Dark Site in RGB-HA
June 20, 2023
Three years after our latest attempt, we decided to shoot the Pinwheel Galaxy again, but this time using our larger refractor telescope and upgraded monochrome camera.
This equipment is set up under Bortle 2 skies in Southern Utah, at a remote observatory called Utah Desert Remote Observatories.
Because we now have this remote setup, we were able to spend many nights on this target and take our time to gather data until being satisfied
We spent a total of 35 hours on this image, using four filters: R, G, B, and HA. We are overall very satisfied with the results. I at first thought that my processing was a bit too purple, but this color on this specific galaxy grew on me and I decided that I liked it as is.
Telescope: Stellarvue SVX130
Mount: 10Micron GM1000 HPS
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nitecrawler focuser / Pegasus Astro Ultimate Powerbox
Processing: Pixinsight, with R-C Astro plugins
Total Exposure Time: 35 hours
Exposure Time per frame: 10 minutes
Filters: Chroma 3nm R/G/B/H
How to Find the Pinwheel Galaxy
The Pinwheel Galaxy is located in the famous Ursa Major constellation and is very easy to spot in the night sky. You can find it just above the double stars Alcor and Mizar, which form the handle of the big dipper. Due to its low surface brightness, you will not be able to spot M101 with the naked eye. It is also a challenge to see through binoculars or a telescope, so a very dark site is a must!
William Herschel took a peek at the galaxy two years after it was discovered by Pierre Méchain and wrote:
“In the northern part is a large star pretty distinctly seen, and in the southern I saw 5 or 6 small ones glitter through the greatest nebulosity which appears to consist of stars. Evening bad. This and the 51st (M51) are both so far removed from the appearance of stars that it is the next step to not being able to resolve them. My new 20 feet will probably render it easy”.
M101 with a Small Refractor and Monochrome Camera
April 23, 2020
Although galaxies are better captured with larger telescopes, we wanted to try imaging it with our small refractor and see if we could still get a beautiful image full of details.
We decided to image M101 while waiting for our main target for the night, Messier 16 to rise. We spent a total of 3.5 hours on it and decided to switch around midnight when the Eagle Nebula was about to be high enough on the horizon.
Camera: ZWO ASI 1600MM
Telescope: Meade 70mm APO
Mount: Equatorial Motorized Mount
Guiding: Autoguider - 50mm Guide Scope
Total Exposure Time: 3.5 hours
Exposure Time per frame: 3 minutes
70 lights - 15 Darks
We are happy with the results and are very glad to have added Hydrogen Alpha to the image as M101 is really full of star formation activity in the spiral arms.
The red blobs you see in the galaxy are all nebulae, star nurseries, and intense gases that can be compared to the nebulae found in our own Milky Way galaxy.
M101 with an 8" Reflector and Stock DSLR Camera
May 11, 2016
Below is our photo taken with an 8” telescope, and a total exposure time of 2.4 hours. We were planning to spend 4 hours on it, but Dalia fell asleep in the trunk of the car after about 2 hours so we had to cut it short... Especially because we had to finish recording our very first Episode of Galactic Hunter!
Camera: Canon t3i
Telescope: 8" Astrograph f/3.9
Mount: Equatorial Motorized Mount
Guiding: Autoguider - 50mm Guide Scope
Total Exposure Time: 2.4 hours
Exposure Time per frame: 6 minutes
24 lights - 20 Darks - 20 Bias
The First Picture Ever Taken of M101
The first astrophotography image of the Pinwheel Galaxy ever taken was done by Isaac Roberts, and was named "Nebula Messier 101 Ursae Majoris".
This picture was shot on the night of May 30th, 1892 using a 20-inch reflector telescope. The total exposure time is three hours and twenty minutes.
This is a beautiful image, which shows great details, is well in focus, and is overall very impressive considering it was taken more than 130 years ago! Good job Isaac, you deserved an APOD.
COOL FACTS About the Pinwheel Galaxy
Contains about 1 trillion stars
70% larger than the Milky Way
Hubble’s M101 was the most detailed image of a galaxy when taken
Single Shot & Processing of M101
Below you can see what a single shot of M101 looked like from a Bortle 2 site at 600 sec. You can easily see the galaxy itself, and even the dwarf NGC 5474 to the left! This is a very promising single frame and when stacked, becomes an amazing image before even starting to process it.
One concern we had with this particular shot is the tilt. Our camera suffered from tilt issues during that time and this gave us a lot of unwanted artifacts, as you see here with the large reflections.
We had to crop the data quite a bit, and work some magic with the background in Photoshop to do our best to hide the reflections.
The Pinwheel Galaxy is really easy to process, the only challenge is to bring out the arms as much as possible and try to show some details in the faint and unimpressive NGC 5474. On the right you can see what the stacked images look like after a quick stretch.
We made a full guide on how to process galaxies on PixInsight using this data of Messier 101 as an example! To learn our exact workflow for processing galaxies, including how to combine HA with RGB, be sure to get the guide which has several lessons, walkthrough videos, downloadable raw data and our custom process icons.
Galactic Hunter Episode #1 - The Pinwheel Galaxy
The Pinwheel Galaxy was the very first target we chose to start our Galactic Hunter channel, so it really means a lot to us!
Messier 101 FAQ
In which constellation is the M101 Galaxy located?
You can find the M101 Galaxy in the constellation Ursa Major.
How big is the Pinwheel Galaxy?
M101 is a large spiral galaxy. It has a diameter of approximately 170,000 light-years.
How far is the Pinwheel Galaxy?
M101 is located approximately 21 million light-years away from Earth.
When was the first picture of the Pinwheel Galaxy taken?
The first picture of M101 was taken on May 30th, 1892, by astronomer Isaac Roberts.
How long should my exposure time be when photographing the M101 Galaxy?
We took 600-second exposures from our Bortle 2 site. We recommend doing between 300 and 600 seconds depending on your equipment. If your telescope is very fast (like an f/2 RASA for example), you can go much shorter, like 180 seconds.
Should I use a filter to image the Pinwheel Galaxy?
M101 is a good broadband target, so you don't need any specific filter to image it. If you'd like to reveal all the star formation regions throughout the spiral arms, then we suggest using an HA filter on top of your RGB/color data.
The Pinwheel Galaxy is a very good target for beginners, and its processing doesn't have any tricky parts! M101 will always hold an important place in our hearts, due to the fact that it was this galaxy that we picked for our first episode of Galactic Hunter.
Antoine checking the mount during the capture of M101 and the filming of the Episode (2016).
Antoine & Dalia Grelin