M13 - The Great Globular Cluster in Hercules

Updated: Aug 31

Messier 13 is one of the best globular cluster to observe and photograph from the Northern hemisphere. It is bright, large, and stays high in the sky for a long period of time.

Photographing this cluster is easy and does not require a lot of exposure time. For the best results, keep your exposure times short to avoid blowing up the bright stars, and always check that your guiding is perfect.

M13 has been targeted on November 16, 1974 to send a message to potential extraterrestrial civilizations. It will take 25,000 years to get there, and the same amount of time for an eventual response.

Attempt #2 - M13 with an 8" reflector and OSC cooled camera

May 25, 2020

Four years after the first attempt, I decided to head back to the desert and revisit this object with our current gear. We used a full frame cooled one shot color camera, the same telescope we had the last time and the Software Bisque Paramount MyT mount.

I spent a total of 1 hour and 45 minutes on the target. I initially wanted to image it for 3 hours, but the laptop died quicker than I anticipated and I had to unplug the camera from the battery in order to charge the computer instead... Then I switched to a different target.

I am very pleased with the result, but had a terrible time trying to take care of the large background halo produced my the bright cluster core. I believe I would not have had this problem if I had an IR cut filter. I did my best during processing but, as you can see below, the background is not really even throughout the image.


Camera: QHYCCD 128C

Telescope: Orion 8" Astrograph f/3.9

Mount: Software Bisque Paramount MyT

Coma: Baader MPCC Coma Corrector MkIII

Guiding: Starshoot Autoguider - 50mm Guide Scope

Processing: Pixinsight


Total Exposure Time: 1 hour and 45 minutes

Exposure Time per frame: 30 seconds

70 lights - 15 Darks

Gain: 3200

Attempt #1 - M13 with an 8" reflector and stock DSLR camera

May 31, 2016

Here was our very first attempt at imaging this bright globular cluster. This was taken with with pretty poor guiding conditions and, to be honest, our processing skills were pretty terrible. Look at how dark the background is!


Camera: Canon 7D Mk II

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 hours

Exposure Time per frame: 3 minutes

40 lights - 15 Darks - 15 Bias

ISO: 400

Locating the Great Globular Cluster in Hercules

The Great Globular Cluster in Hercules can be seen with telescopes, binoculars, and the naked eye! The latter must be seen from a dark zone with no light pollution. Through a telescope, the cluster really looks impressive and many stars can be resolved.

You will find the cluster in the constellation of Hercules and have no issue spotting it! Once you find it, take a moment to think about how Charles Messier found the same cluster many years ago through his own telescope. With his instrument, M13 looked like a nebula!

This is his entry for his famous catalog after having discovered the cluster:

“In the night of June 1 to 2, 1764, I have discovered a nebula in the girdle of Hercules, of which I am sure it doesn’t contain any star; having examined it with a Newtonian telescope of four feet and a half, which magnified 60 times, it is round, beautiful & brilliant, the center brighter than the borders”.

  • Charles Messier thought it was a nebula

  • Cluster is half a million solar masses

  • About 11.65 billion years old

Processing of M13

Processing M13 is not very difficult, but as always with clusters, you will need to be careful to not ruin the stars.

A good thing to do once you are done is to revisit the crispness of the object in a different editing software (we use Lightroom). This usually has a great impact on the final image!

If you centered M13 properly, you might get a galaxy in your frame. This is NGC 6207!

Try to also bring it up during processing using masks, but do not sacrifice any quality in your star cluster for it!

Final Thoughts

Messier 13 is the most famous star cluster for amateur astrophotographers in the Northern hemisphere. It is huge, has more stars than pretty much all others, and is not too difficult to photograph! We plan to revisit this cluster when we get a bigger telescope.

Clear Skies,

Galactic Hunter

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!

#M13 #messier13 #QHY128C #MyT


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