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/