M101 - The Pinwheel Galaxy - DSLR vs Cooled Mono

  • Featured on Orion Telescopes & Binoculars 2016 Holiday Catalog, page 41.

  • Featured on Orion Telescopes & Binoculars "featured member" webpage.

  • Featured on The Astrophotographer's Guidebook.

M101 is a rather large spiral galaxy that is seen face-on. While difficult to see, it is an easy target for astrophotographers. We have photographed the Pinwheel galaxy twice, once with our Orion 8" Astrograph and stock Canon T3i DSLR camera, and 4 years later with our small Meade refractor telescope and ASI 1600MM camera.

The Pinwheel Galaxy appears symmetrical at first, but long exposures reveal that it is obviously not. The reason for that is its dwarf companion (seen on top right of left image) 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.

Attempt #2 - 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 was about to be high enough in the horizon.


Camera: ZWO ASI 1600MM

Telescope: Meade 70mm APO

Mount: Atlas EQ-G motorized Mount

Coma: Baader MPCC Coma Corrector MkIII

Guiding: Starshoot Autoguider - 50mm Guide Scope

Processing: Pixinsight


Total Exposure Time: 3.5 hours

Exposure Time per frame: 3 minutes

70 lights - 15 Darks

Gain: 139

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.

Attempt #1 - 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: 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: 2.4 hours

Exposure Time per frame: 6 minutes

24 lights - 20 Darks - 20 Bias

ISO: 800

Locating 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”.

  • 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 our DSLR single shots of M101 looked like. You can easily see the galaxy itself, and even the dwarf NGC 5474! This is a very promising single frame and when stacked, becomes an amazing image before even starting to process it.

The Pinwheel Galaxy is really easy to process, the only challenge is to bring out the arms as much as possible, and trying 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.

Make sure that you correctly do the Background Extraction step, or you will have a grainy image to work on for the rest of the processing.

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!

Final Thoughts

The Pinwheel Galaxy is a very good target for beginners, and its processing doesn't have any tricky part!

M101 will alway 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).

Clear Skies,

Antoine & Dalia Grelin

Galactic Hunter

Galactic Hunter Books

Part of: 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!

#DSLR #Meade70mm #M101 #Pinwheel #Pinwheelgalaxy

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