How to find the Keystone
When to look
June, July, August evenings
Face high overhead
Four stars in a lopsided box, a little wider at the top, about a third of the way from Vega towards Arcturus. Summer evenings, June to August, very high overhead; it sinks into the west through autumn. The drawing below is made from the real positions of its 5 stars, as the sky looks when you face it, with bigger dots for brighter stars. No telescope needed.
The Keystone is four stars in a box shape, high up on summer nights. It is the middle of a big constellation called Hercules.
The Keystone is the middle of the big, faint constellation Hercules. Look about a third of the way from Vega towards Arcturus for its four stars. A keystone is the wedge-shaped stone at the top of an arch, and the four stars make that shape.
On the Keystone's western side, between its two stars there, binoculars show a small fuzzy dot: the Great Globular Cluster, M13, a ball of several hundred thousand old stars about 25,000 light-years away. In 1974, a radio message was beamed from Earth towards it.
The stars in it
Zeta, Eta, Pi, Epsilon, Kornephoros. The brightest is Zeta.
How to find it
- Go out after dark with a grown-up, and give your eyes ten minutes away from screens.
- Face high overhead and look for: four stars in a lopsided box, a little wider at the top, about a third of the way from Vega towards Arcturus.
- Hold up this page's drawing or the printed card and match the shape to the sky. If the sky is clear.
More star patterns
“Star patterns turn through the night, so the shape may be tipped on its side. Turn your head, not the sky.”