In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shows itself to the naked Eye, when the Sky is serene and the Moon absent." Of course, M13 is now less modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky. Sharp telescopic views like this one reveal the spectacular cluster's hundreds of thousands of stars. At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter. Approaching the cluster core, upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison, the closest star to the Sun is over 4 light-years away. The remarkable range of brightness recorded in this image follows stars into the dense cluster core.
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture Of the Day
Publications with keywords: M 13 - globular cluster
Publications with words: M 13 - globular cluster
- M15: Dense Globular Star Cluster
- NGC 2419: Intergalactic Wanderer
- NGC 4372 and the Dark Doodad
- Millions of Stars in Omega Centauri
- APOD: 2023 February 20 ┴ NGC 1850: Not Found in the Milky Way
- APOD: 2023 January 30 ┴ Globular Star Cluster NGC 6355 from Hubble
- M13: The Great Globular Cluster in Hercules