Messier 4

Messier 4 can be found west of bright red-giant star Antares, alpha star of the constellation Scorpius. Messier 4 itself is only just visible from dark sky locations, even though the globular cluster of 100,000 stars or so is a mere 5,500 light-years away.

Still, its proximity to prying telescopic eyes makes it a prime target for astronomical wonders and explorations. Recent studies have included Hubble Image observations of Messier 4’s pulsating Cepheid Variable stars, cooling White Dwarf stars, and ancient, Pulsar orbiting Exoplanet PSR B1620-26 b.

This sharp astrophotography image was captured with a small telescope on Planet Earth. At Messier 4’s estimated distance it spans about 50 light-years across the core of the star cluster.