How to See the Leo Triplet (M65, M66 & NGC 3628) Through a Telescope
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The Leo Triplet of galaxies M65, M66, and NGC 3628 as captured by Hubble — three interacting spiral galaxies

Observing Guide · Galaxy Group

How to See the Leo Triplet (M65, M66 & NGC 3628) Through a Telescope

The Leo Triplet is one of the finest galaxy groupings in the spring sky — three spiral galaxies (M65, M66, and NGC 3628) packed into a field just 1 degree across, all visible in the same low-power eyepiece. Each galaxy has a distinct personality: M65 is a smooth, elongated spiral with a bright core; M66 is larger and more open, with obvious spiral structure; and NGC 3628 is a spectacular edge-on galaxy bisected by a dark dust lane. This guide covers everything you need to observe all three.

Object typeGalaxy triplet
Apparent magnitude9.3 / 8.9 / 9.5
Best seasonMarch – June
Min. aperture100mm sees all three
By Elena ReyesPublished: Updated: Reviewed & approved by Juhi Sahni, Senior Editor Editorial Standards

Quick Answer: What Telescope Do I Need for the Leo Triplet?

All three galaxies are visible in any telescope with at least 100mm (4-inch) aperture under dark skies. Through a 100mm refractor at 40–50×, M65 and M66 appear as two elongated patches of light close together, with NGC 3628 fainter but detectable as a thin streak. A 150mm (6-inch) scope at 60–80× reveals all three clearly: M65 appears smooth and oval, M66 shows a brighter core with a slight asymmetry (evidence of its spiral arms), and NGC 3628 is visible as a long, thin cigar with a faint central bulge. An 8-inch (200mm) Dobsonian at 100× shows the dark dust lane in NGC 3628 and hints of spiral structure in M66. The triplet spans just 1 degree, fitting perfectly in a wide-field eyepiece.



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How to Find the Leo Triplet in Leo

The Leo Triplet lies in the constellation Leo, about 5 degrees south of the bright star Regulus (Alpha Leonis, magnitude 1.4) and 3 degrees east of Iota Leonis. The easiest approach: locate the Sickle of Leo (the backwards question mark asterism marking the Lion's head and mane), then star-hop from Regulus south to the triangle of stars formed by Iota, Tau, and 73 Leonis. The triplet sits just east of 73 Leonis. In a finder scope, M65 and M66 are visible as two faint fuzzy patches close together — once located, sweep south slightly to pick up NGC 3628.

The Leo Triplet is best observed from March through June, when Leo is high in the southern sky during evening hours. The constellation culminates around midnight in April and is well placed from late evening through the early morning hours during spring. The galaxies reach an altitude of 60–70 degrees from mid-northern latitudes, well above the worst of the atmospheric turbulence near the horizon.

What the Leo Triplet Looks Like Through Different Apertures

InstrumentBest MagnificationM65M66NGC 3628
100mm (4")40–50×Small oval glow with brighter core.Slightly larger oval. Core visible.Faint thin streak. Requires averted vision.
150mm (6")60–80×Smooth oval. Core sharply defined.Asymmetric halo hints at spiral arms.Clear cigar shape. Central bulge visible.
200mm (8") Dob80–100×Bright oval with extended outer halo.Spiral arms visible as arcs. Core bright.Dark dust lane visible as a notch. Long thin edge-on.
300mm (12")+120–200×Well-defined oval. Dust lanes in inner region.Clear spiral arms with star-forming knots.Dust lane splits the galaxy. Bright core on one side.

The Science Behind the Triplet

The Leo Triplet, also known as the M66 Group, is a small group of interacting spiral galaxies approximately 35 million light-years away. The three galaxies — Messier 65, Messier 66, and NGC 3628 — are gravitationally bound and have been interacting over the past billion years. This interaction has distorted all three galaxies: M66's asymmetric spiral arms, NGC 3628's spectacular dust lane and extended tidal tail, and M65's slightly warped disc all bear the signature of their gravitational dance.

NGC 3628, the faintest of the three, has a giant tidal tail extending over 300,000 light-years — longer than the entire Milky Way — visible in deep photographs but beyond the reach of amateur telescopes. This tail was formed by tidal forces stripping gas and stars from NGC 3628 during a close passage near M66. The trio is one of the most popular targets for amateur astrophotographers, who can capture all three galaxies and the faint tidal stream in a single wide-field image.

Best Telescopes for the Leo Triplet

A 6-inch or 8-inch Dobsonian at low power is the ideal instrument for the Leo Triplet. The 1-degree field fits all three galaxies with room to spare, and moderate aperture brings out the dark lane in NGC 3628 and the spiral asymmetry in M66. For telescope recommendations, see our best Dobsonian telescopes guide. For those who prefer GoTo convenience for galaxy-hopping, see our best computerized telescopes guide.



Frequently Asked Questions

What telescope do I need for the Leo Triplet?

A 100mm (4-inch) scope shows all three galaxies at 40–50×. A 6-inch scope reveals detail including NGC 3628's shape. An 8-inch shows the dark dust lane.

How do I find the Leo Triplet?

Start at Regulus (Leo's brightest star), go about 5 degrees south to Iota Leonis, then 3 degrees east. The triplet sits near 73 Leonis.

Can I see all three galaxies in one field?

Yes — the triplet spans just 1 degree. A wide-field eyepiece at 40–50× fits M65, M66, and NGC 3628 all in the same view.

Which is the brightest galaxy in the Leo Triplet?

M66 is brightest at magnitude 8.9, followed by M65 at 9.3 and NGC 3628 at 9.5. M66 also shows the most detail in moderate apertures.

When is the best time to observe the Leo Triplet?

From March through June, when Leo is high in the evening sky. Best around midnight in April.

What is special about NGC 3628?

NGC 3628 is an edge-on spiral with a prominent dark dust lane splitting its disc — visible in 8-inch scopes. It has a giant 300,000-light-year tidal tail from interaction with M66.