
The Leo Triplet
NGC 3628, M65, M66 • Galaxy group • Leo • 35 million light-years from Earth
🔭
Askar 130PHQ
📷
ZWO 2600MC Pro
🌃
Bortle 8
⏱️
21 hours
🗓️
April 2026

Overview
This imaging project showcases the Leo Triplet, a trio of spiral galaxies in the constellation Leo: Messier 65, Messier 66, and the edge-on NGC 3628. Featuring dramatic dust lanes and gravitational interactions, the Leo Triplet is a prime astrophotography target that’s achievable even from light-polluted skies.
Background
Galaxy season is a tough time for me, because my telescopes don’t have the very long focal length required to do justice to individual star cities. Instead, when possible I try to find collections of galaxies that I can image together, filling the frame. The Leo Triplet fits this bill nicely, and to be honest I’m surprised I’ve never imaged it before!
The final image has an integration time of 21 hours, which was enough to bring out some good details in the galaxies themselves. I wasn’t able to get the tidal tail that’s coming out of NGC 3628, alas; light pollution is a killer for faint details like that.
I used my Optolong L-Quad Enhance filter, which is very useful for combatting light pollution. It also lets a decent amount of Hydrogen-alpha through, which is a boon for galaxies that have star-forming regions.

Close-ups
Science
The Leo Triplet is a small group of spiral galaxies located roughly 35 million light-years away in the constellation Leo. It consists of NGC 3628, Messier 65, and Messier 66. Together they form a gravitationally interacting system within the larger Leo I Group.
Although each galaxy is its own individual structure, their mutual gravitational influence has shaped them, creating warped disks, extended tidal features, and spiral arms that have, in effect, been pulled out of shape.
NGC 3628 is sometimes nicknamed the Hamburger Galaxy. It has a thick central dust lane, which is made from cold material blocking starlight. It’s quite well known for having a large tidal tail, but I need a longer integration time to capture that.

M65 is the least gravitationally disturbed of the Trio, meaning it looks more like a “regular” galaxy. It features modest levels of star formation, with lots of older stars around its core and central regions.

M66 may be my favourite of the three. The gravitational influence of NGC 3628 is readily seen, and I think it’s quite easy to imagine invisible forces pulling at the spiral arms, bending them out of shape. This “mixing up” of material has led to intense areas of star formation within M66. Although my data is broadband, my Optolong L-Quad Enhance filter is pretty good at pulling out Hα, so these star-forming regions show up in my image as reddy-orange patches.

5 vs 21 hours
I actually tried imaging the Leo Triplet last month, but only collected five hours of data before dodgy Flats and a run of bad weather caused me to abort the mission. It’s interesting to see how much more detail is visible with longer integrtation times though. See below for slider image examples; 5 hours is on the left, 21 on the right.






Kit list
This is the equipment I used to capture the image.
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Telescope: Askar 130PHQ
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Camera: ZWO ASI 2600MC Pro
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Mount: StellarDrive X 6R PRO
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Rebuilt into a StellarDrive X 6R PRO by DarkFrame Optics.

Askar M54 Off-Axis Guider
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ZWO ASI 220MM Mini
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Control: ASIAIR Plus
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Filter: Optolong L-Quad Enhance
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Processing walkthough
Example source data
Here are example single subframes and freshly integrated stacks, just with simple stretches applied.


Seestar S50 image
Here’s are the Leo Triplet imaged using my Seestar S50 telescope from my Bortle 8 city centre.

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