The Messier Ten Minute Challenge

M13 - Globular Cluster in Hercules

Discovered by Halley in 1714, M13 (NGC 6205) is one of the most
prominent and best known globulars in the northern hemisphere. At a
distance of 25,100 light years it is 145 light years across.

http://www.martin-nicholson.info/ten...llenge/m13.htm

Martin Nicholson, Daventry, England.

My website is at http://www.martin-nicholson.info/1/1a.htm
My informal Astronomical Blog is at http://ukastronomy.livejournal.com/