The Leo Triplet (M65, M66 & NGC 3628)

Three spiral galaxies bound by gravity in the constellation Leo, each presenting a different orientation to our line of sight — together offering three distinct perspectives on the spiral galaxy form in a single field of view.

The Leo Triplet sits around 35 million light-years away in Leo. M65 and M66 are a classic interacting pair whose mutual gravity has subtly distorted both structures over billions of years. NGC 3628, the third member, presents almost perfectly edge-on — its disk bisected by a prominent dust lane and its outer arms slightly warped by the same gravitational interaction.

Having all three in one field makes this one of the most compositionally satisfying galaxy targets in the sky. The variety of orientations — M65 slightly inclined, M66 more face-on, NGC 3628 edge-on — means each tells a different part of the story of what a spiral galaxy is.

NGC 3628 has a faint tidal stream — a trail of stars pulled out by the gravitational interaction with its neighbours. It requires significant integration time and careful processing to reveal, but is a worthwhile challenge for a revisit.