M9 - Globular Cluster in Ophiuchus Astrophotography
Messier 9 is a globular cluster in the constellation of Ophiuchus. It doesn't have a nickname and isn't a popula target to photograph.
Object Designation: M9, NGC 6333
Constellation: Ophiuchus
Object Type: Globular Cluster
Distance: 25,800 light-years away
Magnitude: 7.9
Discovered on: June 3 1764 by Charles Messier
I imaged M9 in RGB+HA as I was hoping to see some hydrogen alpha gas in the background, like I did for a few clusters recently. I spent a total of 7 hours on this, which probably should have been more as it was a difficult one to process due to the noise!
In the northern hemisphere, Messier 9 is best observed and photographed in the Summer months.
Messier 9 Astrophotography with a Monochrome Camera in RGB-HA
May 2024
I shot and processed this image of Messier 9 in May 2024, but I waited until January of 2025 to post it here as I did not love the results. Indeed, the final image was very tough to get without it looking very noisy and looking patchy because of how faint the HA gas and what seems to be IFN was. It would be very easy to re-process this image with a cleaner result, but that would mean not caring about bringing out that dim gas.
I decided to just be done with it and upload it as is until I decide to reshoot it in the future. I only wish I spent at least 25 hours on it!
Click the picture to see it in full resolution!
Learn how to process your data like this with our PixInsight processing guides.
GEAR USED:
Camera: QHY600M
Telescope: Stellarvue SVX130
Mount: 10Micron GM1000 HPS
Accessories: Moonlite Nitecrawler focuser / Pegasus Astro Ultimate Powerbox
Processing: Pixinsight with RC-Astro plugins, final touches in Skylum Luminar Neo
ACQUISITION DETAILS:
Total Exposure Time: 7 hours
Exposure Time per frame: 10 minutes
Filters: Chroma 3nm RGB+HA
Gain: 56
How to Find Messier 9
Messier 9 is best observed during the late spring and summer months in the Northern Hemisphere.
To find it, first locate the bright star Antares in the neighboring constellation Scorpius, then look slightly northward to identify Ophiuchus. From the star Sabik (Eta Ophiuchi) in the southeast part of Ophiuchus, M9 is about 3° to the east-southeast.
M9 lies about 25,800 light-years from Earth and appears as a small, fuzzy spot through binoculars. With a medium to large telescope (6-inch aperture or larger), you can start to resolve some individual stars.
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Processing 9
Like I said earlier, this was a very tough one to process! What's funny is that if one doesn't care about the faint gas (HA and IFN) in the vicinity, then this cluster is extremely simple to process. All you'd have to do is a quick and basic workflow for brightness, contrast, and saturation. But because my main goal was to show these dim gasses, I had to do my best to use masks and other means to reveal them against the dark background.
Making very faint gas brighter, even with masks, tends to bring out a lot of noise. This was especially difficult as 7 hours of total integration was not enough to get a good signal to noise ratio in this case. Several iterations of NoiseXTerminator had to be used to get something somewhat OK for export.
As for the processing, you can learn how to process your images the same way I do by getting our guides HERE.
Final Thoughts
The Messier 9 cluster is a small and dense globular cluster that can be a good secondary target to end a Summer night. Make sure to decide right away if you plan to just have a picture of the cluster on a dark featureless background sky, or if you'll aim to reveal the IFN and Hydrogen Alpha gas. If you choose the latter, be sure to spend as many hours on it as possible when shooting it with your telescope so that you can get less noise when processing it!
Have you captured M9? Attach your image in the comments and let us know what equipment you used!
Clear Skies,
Galactic Hunter
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