History

The globular cluster Messier 19 was added to his list of «diffuse stars» by Charles Messier in June 1764, four days after the discovery of M 14. In 1784 Sir William Herschell was probably the first, who was able to resolve Messier's diffuse star with his large reflecting telescope into single stars and who recognized the true nature of M 19.

Physical Properties

The vicinity of M 19 as seen by us is very rich in stars and appears peppered with countless small stars in our Milky Way. The globular cluster is located near the central bulge of our galaxy. The distance from the galactic center is estimated to be around 3000 light years. The cluster appears to be a little further away than M 10 or M 12. The light is also weakened by interstellar dark dust, which makes exact distance measurements difficult. Published distances vary from 20'000 to 30'000 light years. M 19 moves away from the solar system at a radial speed of about 100 km/s.

M 19 belongs to the flattened globular clusters. It shows an elliptical outline. H. Shapley estimated that there are about twice as many stars along the long axis as there are along the short axis. The integrated spectral type is indicated with F5. ^[4]

Finder Chart

The globular cluster Messier 19 is located in the constellation Serpent Bearer (Ophiuchus) and is best observed in the months May to July.