Messier 14 — Globular Cluster in Ophiuchus

M14 is a globular cluster in the constellation Ophiuchus, located about 30,300 light-years from Earth. It contains several hundred thousand stars packed into a sphere roughly 100 light-years in diameter. At magnitude 7.6 with an apparent diameter of about 11 arcminutes, it is one of the fainter Messier globulars. M14 has a moderately concentrated core with a Shapley-Sawyer concentration class VIII. The cluster is notable for containing a large number of variable stars and for an unusual population of carbon stars.

Located about 10 degrees south of M10 and M12 in Ophiuchus. At magnitude 7.6, it requires binoculars to see as a small, round fuzzy patch. A 4-inch telescope at 100x shows a round glow with a brighter center, but star resolution is difficult. Apertures of 10 inches or more at 200x begin to resolve the granular outer regions. M14 is less visually impressive than many other Ophiuchus globulars but rewards patient observation with larger scopes. Best observed from June through August.

Discovered by Charles Messier on June 1, 1764. He described it as a round nebula without stars. It remained unresolved for many years until larger telescopes were available. In 1938, a nova was discovered on photographic plates taken of M14 — only the second nova ever found in a globular cluster. It had reached magnitude 9.2 but was only noticed years after the event.