History

This globular cluster was discovered by Charles Messier on 1 June 1764. He listed it as 14th entry and described it with the following words: «Starless nebula, discovered in the drapery that passes through the right arm of Ophiuchus, and placed on the parallel of ζ Serpentis: this nebula is not large, its light is faint, yet it can be seen with an ordinary telescope of three and a half feet; it is round, and near it is a small star of the ninth magnitude; its position was determined by comparing it to γ Ophiuchi, and Mr. Messier reported its position on the Map of the Comet of 1769. Memoirs of the Academy, year 1775, plate IX. Reviewed on March 22, 1781.» ^[281]

About two decades later Sir William Herschel observed the objects found Messier and recognized the true nature of many of these «nebulae». He wrote: «The excellent collection of nebulae and clusters of stars which has lately been given in the Connoissance des Temps for 1783 and 1784, leads me next to a subject which, indeed, must open a view of the heavens. As soon as the first of these volumes came to my hands, I applied my former 20-feet reflector of 12 inches aperture to them; and saw, with the greatest pleasure, that most of the nebulae, which I had an opportunity of examining in proper situations, yielded to the force of light and power, and were resolved into stars. For instance the 2d, 5, 6, 10, 12, 13, 14, 15, 16, 19, 22, 24, 28, 30, 31, 37, 51, 52, 53, 55, 56, 62, 65, 66, 67, 71, 72, 74, 92, all which are said to be nebulae without stars, have either plainly appeared to be noting but stars, or at least to contain stars, and to shew every other indication of consisting of them entirely.» ^[27]