ObserveTheSky › Everything in the sky › The Hercules Cluster (M13)

Where is the Hercules Cluster in the sky?

You will want binoculars for this one. North of the equator it is best placed in the summer.

How to find the Hercules Cluster

Look in the constellation Hercules.

Best placed from the Northern Hemisphere.

What it takes: A classic bright target for binoculars or any telescope.

Finding it: On the western side of the Keystone of Hercules, a third of the way from Eta to Zeta Herculis.

On the sky it is about 20 arcminutes across, where the full Moon is 30.

Its nearest bright landmark is Alphecca, in Corona Borealis — 17.2° away, or about 1.5 fists at arm’s length.

Your own sky, right now.

Open in the Planetarium

When can I see the Hercules Cluster?

From the Southern Hemisphere, look in the winter.

It rises above the horizon everywhere north of latitude 53.5° south.

What the shading meansClose

This is the Earth. Where the globe is clear, this object climbs high in the sky; the darker the shading, the lower it stays; where the globe is black, it never rises at all. If the globe has no shading, it does not matter where on Earth you are.

What the Hercules Cluster looks like in different instruments

With your own eyes

A faint fuzzy “star” that never quite comes into focus — and only from a really dark place. It stays a smudge because it is not one star; pulling the smudge apart is what a telescope is for.

With 10×50 binoculars

Binoculars show it as a small, soft, grey patch. Not the photograph — but unlike the photograph, its light is reaching your eyes right now.

The Hercules Cluster (M13) through 10×50 binoculars10×

Through a small telescope (a 150 mm Dobsonian)

A round glow with a bright core; at higher power its edges break up into countless faint stars.

The Hercules Cluster (M13) at 25× through a 150 mm telescope25×
🔭 See it drawn as it looks through a telescope
Show the Hercules Cluster in the model📖 More details about the Hercules Cluster🕒 When can I see the Hercules Cluster?🌙 Plan an evening outside