APOD: 2022 August 4 - M13: The Great Globular Cluster in Hercules

Good afternoon, Rallypoint, and welcome to the August 4th edition of Astronomy Picture of the Day (APOD): "M13: The Great Globular Cluster in Hercules." This rendition of M13 is one of the better ones that have appeared as an APOD. Over 7 hours of exposure time (June 22-23, from Spain) was used to produce this composite image. In 1716, Edmond Halley first described today's APOD as "...but a little Patch, but it shows itself to the naked Eye, when the Sky is serene and the Moon absent." Using Halley's initial observations, Charles Messier placed the Great Globular Cluster in Hercules (M13) in his catalog in 1764.

Halley's "little Patch" of sky has an estimated 300,000 stars packed into an area 150 light years across. M13 lies about 25,000 light years from Earth.