Imaging The Butterfly Cluster (M6)

Sitting in the constellation Scorpius, just above the stinger of the scorpion, is Messier 6 (M6), better known as the Butterfly Cluster. And yes — it really does look like a butterfly in flight, with two sweeping wings of stars spread across the sky.

This is an open star cluster about 1,600 light-years away, containing around 100 young stars. Most of them are hot, blue, B-type stars shining brilliantly against the backdrop of the Milky Way. But what makes M6 truly pop is its brightest star, an orange K-type giant named BM Scorpii, which adds a warm amber glow to an otherwise blue-white sea of light.

At only 100 million years old, M6 is practically a cosmic teenager compared to ancient globular clusters. Through binoculars, it’s a dazzling sprinkle of diamonds. Through a telescope, the “butterfly” shape really flutters to life.

First noted by Giovanni Battista Hodierna in 1654 and later catalogued by Charles Messier in 1764, it’s one of the southern sky’s most breathtaking clusters — best seen on warm winter nights here in Australia when Scorpius dominates the north.

When to See It

M6 is best observed during the winter months in the Southern Hemisphere (June–August), when Scorpius is high overhead in the evening sky. From Australia, it’s ideally positioned, rising high above the horizon for optimal viewing. If you’re in the Northern Hemisphere, you’ll need to look for it lower in the southern sky during summer.

Observing the Butterfly Cluster

Visually, M6 is a treat for binoculars and small telescopes. Under dark skies, even a pair of 10x50 binoculars will reveal the cluster’s wings, while a small telescope will start to resolve individual stars. Wide-field eyepieces are ideal because you’ll want to take in the whole cluster at once rather than zoom in too tightly.

Top tip: try scanning the area just above the stinger stars of Scorpius, Shaula and Lesath, and you’ll find M6 floating nearby.

Astrophotography Tips

For astrophotographers, the Butterfly Cluster is a classic wide-field target, sitting in the Milky Way’s dense star fields. A fast refractor or Newtonian with a wide field of view makes capturing it easier, as it’s a sprawling object with lots of background stars to contend with.

For my image, I used my Sky-Watcher Quattro 150P telescope paired with a ZWO ASI533MM Pro camera and Antlia, RGB filters. This combo gives crisp, high-contrast images while keeping the stars beautifully sharp. Since this is an open cluster, colour balance is everything – pulling out the cooler blues and the warmer oranges really makes the “butterfly” pattern come alive.

Best Equipment to Use

• Binoculars (10x50 or larger) – for casual stargazing and spotting the wings of the butterfly.

• Small refractor telescope (60–80mm) – for wide-field observing and astrophotography.

• Newtonian reflectors (like the Sky-Watcher Quattro 150P) – ideal for deep-sky imaging.

• Cameras – DSLR or dedicated astronomy cameras work well, especially with short to medium exposures.

Imaging Tips

• Use short exposures to keep the stars sharp and avoid blowing out the bright cluster members.

• A wide field of view will frame the cluster nicely against the Milky Way.

• Stack multiple frames to reduce noise and reveal faint stars on the edges.

Why You’ll Love It

The Butterfly Cluster isn’t just pretty – it’s also a stellar nursery snapshot, giving us a peek into the evolution of young stars. While some members are still hot and blue, others like BM Scorpii are already ageing, showing how quickly massive stars burn through their fuel.

So whether you’re out with binoculars, a telescope, or your camera, M6 is one of those “must-see” southern sky gems. And honestly, who doesn’t want to say they’ve caught a butterfly in the stars?