Messier 19 with amateur telescope. Image source: [1]
After talking about the spectacular Omega Nebula (Messier 17), we have to focus on Messier 19.
In the 18th century, while searching for the night sky of comets, the French astronomer Charles Messier began to notice a series of "nebulous objects" in the night sky. In the hope of making sure other astronomers do not make the same mistake, he began to compile a list of these objects. Known to posterity as the Messier Catalog, this list has become one of the most important milestones in the investigation of deep sky objects. One of these objects is Messier 19, a globular star cluster located in the constellation of Ophiuchus. Of all known globular clusters, Messier 19 appears to be one of the most flattened (ie, flatter) in the night sky. Discovered by William Herschel, this group is relatively difficult to detect with the naked eye, and appears as a diffuse point of light with the help of magnification.
Messier 19 has an age of 11.9 billion years, has a diameter of about 140 light years and moves away at a rate of 146 k/s. It is about 27,800 light-years away from our planet, and is one of Messier's closest objects to the center of the Milky Way, only 6,500 light years away. That proximity to the nucleus of the galaxy is responsible for being one of the globular clusters with the most pronounced ellipsoid form. It has more stars in its major axis (the longest axis of the ellipse) than in the minor axis. It is not easy to determine the number of stars inside it, but we do know that it has a mass about 1,100,000 times that of the Sun. Four RR Lyrae stars have been detected inside.
More details here: Messier 19
Messier 19 by Hubble Space Telescope; 2.5′ view. Image credit: NASA/STScI/WikiSky