The Leo Triplet, also called the M66 group, is a small group of spiral galaxies in the constellation Leo.
The Leo Triplet is composed of two Messier objects, M65 and M66, as well as NGC 3628, which is also called the Hamburger galaxy due to its shape. Discover more about each of these deep-sky objects and how to photograph them together.
Object Designation: M66 Group, Arp 317
Also known as: The Leo Triplet
Object Type: Spiral Galaxies
Distance: 35 million light-years away
Magnitude: 9.3, 8.9, 9.5
Discovery: M65/M66: Charles Messier in 1780. NGC 3628: William Herschel in 1784.
The Leo Triplet is best photographed in the Spring season, also known as "Galaxy Season". When photographing this target, make sure you aim your camera properly so you can get all three of the galaxies showing nicely in your frame. We imaged the Leo Triplet several times with different setups, and you will see our results below!
The Leo Triplet Astrophotography with LRGB Filters
The picture you see here was taken from a Bortle 2 site at Utah Desert Remote Observatories using our 5" refractor telescope and full-frame monochrome camera. It totals 12 and a half hours of integration time using four filters (L, R, G, B). You can see the long dust tail coming off from the Hamburger Galaxy which is cool and was the reason why we used the L filter! Click the image to see the full-resolution version.
This was a very challenging image to process, and you'll understand why later in this post!
Telescope: Stellarvue SVX130
Mount: 10Micron GM1000 HPS
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nitecrawler focuser / Pegasus Astro Ultimate Powerbox
Processing: Pixinsight, with RC-Astro plugins
Total Exposure Time: 12.5 hours
Exposure Time per frame: 10 minutes
Filters: Chroma 3nm L/R/G/B
How to Find the Leo Triplet
The Leo Triplet can be found in the constellation of Leo, not far from Ursa Major and Virgo. To locate it, first, find the star Chertan which makes up part of the back legs of the lion, then move down towards Virgo. You are likely to land on at least one of the three galaxies, so missing the remaining two is nearly impossible.
In dark skies, far from any light pollution, all three galaxies can be observed through binoculars. A telescope with a focal length between 500 mm and 800 mm is ideal for viewing the group in one field of view.
The most popular spiral galaxy for amateur astrophotographers is the Andromeda Galaxy (M31).
Leo Triplet Galaxies Information
The Leo Triplet is made up of three galaxies, M65, M66, and NGC 3628. The first two are Messier objects and were discovered by Charles Messier in 1780. The third one, NGC 3628, was found four years later by William Herschel.
About Messier 65
Messier 65 is a spiral galaxy located about 35 million light-years away from Earth, and it is situated in the northern portion of this trio. The galaxy has a spiral structure with prominent arms that sweep outward from its core. In its spiral arms are young, hot stars, of vibrant blue color, contrasting with the older, redder stars found in the central regions.
A supermassive black hole is at its center, exerting a powerful gravitational influence on its surroundings. It also has intricate dust lanes that run along its arms which partially obscure some regions.
About Messier 66
Messier 66 is a spiral galaxy located approximately 36 million light-years away from Earth and is the southernmost member of this trio. This galaxy has an intricate and beautiful spiral structure, with tightly wound arms that extend from a bright center. Similar to M65, it has blue and red stars in its spiral bands.
Messier 66 has intense star-forming activity, with numerous star clusters and nebulae scattered throughout its spiral arms. The galaxy also holds a bright, elongated core, which is home to a supermassive black hole.
About NGC 3628
NGC 3628, also known as the Hamburger Galaxy or the Needle Galaxy, is a great target for beginner astrophotographers. Located approximately 35 million light-years away in the constellation Leo, NGC 3628 is one of the members of the famous Leo Triplet, a group of three interacting galaxies.
The object is seen edge-on. The galaxy looks like a long, narrow streak of light, and appears like a cosmic needle or a cosmic hamburger, depending on what you choose to see! NGC 3628 has dark dust lanes that run across its equatorial plane, creating visual interest for astrophotographers.
DSLR Crop on Messier 65 (left), Messier 66 (middle), and NGC 3628 (right).
The Leo Triplet Astrophotography with a DSLR Camera
Our first attempt at capturing the Leo Triplet was in March 2018 using our stock Canon 7D Mark II camera and 8" Newtonian telescope. The result turned out beautiful as you can see below, with just under 4 hours of exposure time and imaging from a Bortle 4 zone.
Camera: Canon 7D Mark II
Telescope: 8" Newtonian
Mount: Equatorial Motorized Mount
Guiding: Autoguider - 50mm Guide Scope
Total Exposure Time: 3.45 hours
Exposure Time per frame: 3 minutes
69 lights - 15 Darks - 15 Bias
Single Shot and Processing of the Leo Triplet
The Leo Triplet can be a little scary to process for beginners who have never photographed more than one galaxy at a time before. Thankfully, all three of those galaxies are similar in size, color, and brightness, which makes the editing part much simpler than expected!
Below you can see what each master looked like, from left to right L, R, G and B.
Now why did we say earlier that this was a very challenging image to process? This is because our telescope currently suffers from tilt, and our data gets ruined by unwanted artifacts whenever we shoot too close to bright stars. In this case, several bright stars were located just outside of the frame, and their glow gave us a lot of reflections left and right as you can see below... This was a huge pain to remove and very time-consuming.
Luckily, the reflections stopped before reaching the galaxies.
To remove these reflections, I of course cropped as much as I could but ensured that the dust tail from the Hamburger Galaxy was still full. I then proceeded to remove the rest using clone stamp on both PixInsight and Photoshop after removing the stars. Because there are a lot of background galaxies, I had to be very careful to only clone complete darkness to keep the image fully scientifically accurate.
Cool Facts About the Leo Triplet
May be part of a bigger group
Messier 66 is the brightest of the three
All deformed by each other's gravity
Discover more about the galaxies we've photographed on our galaxies gallery page.