Charles Messier (May 30, 1764):
'Cluster of a great number of small stars which can be seen in a good telescope. In a 3-foot focal length instrument it looks like a comet. The cluster is mingled with a faint light. 8th magnitude star is in cluster. Seen by Kirch in 1681. Reported on the English Great Atlas.'
Gottfried Kirch (Discovered M-11 in 1681):
'A small obscure spot with a star shining through and rendering it more luminous.'
Walter S. Houston:
'"....a carpet of sparkling suns to the very center with outliners swarming on all sides. A good 10-inch shows hundreds of glittering star points all over the field of view..'
Quote from Dreyer's New General Catalog(NGC) for NGC 6705:
'Remarkable!, cluster, very bright, large, irregularly round, rich in stars, 9th magnitude star, stars of magnitude 11 and fainter; = M11.'
Quote from Burnham's Celestial Handbook:
"Exceptionally fine galactic star cluster, lying on the north edge of the prominent Scutum Star Cloud, and one of the outstanding objects of its type for telescopes of moderate aperture."
Gottfried Kirch, an astronomer at Berlin Observatory, discovered M-11 in 1681. In 1715 Halley included it in his list of six 'nebulous stars', and finally in 1732, English amateur astronomer William Derham was the first to recognize that M-11 was a star cluster not a nebula.
According to Burnham's there are at least 870 stars visible, plus another 800 invisible companions, with a total mass 2,900 times that of the sun. The distance is about 5,500 light years, considerably closer than the Scutum Star Cloud. An observer at the center of M-11 would see several hundred 1st magnitude stars in his sky, and possibly 40 or so much brighter than Sirius. These are truly bright stars: if the sun was at the same distance it would be magnitude 15.9. The estimated age of the cluster is 500 million years.
George Normandin, KAS
June 3rd, 2006