M70

M70 is a compact globular cluster in Sagittarius, about 29,300 light-years from Earth. It is very similar to its neighbor M69 in distance, size, and brightness. The cluster has undergone core collapse, giving it an extremely dense central region. M70 is historically notable as the location where Comet Hale-Bopp was discovered in 1995.

Located about 2 degrees east of M69, near Epsilon Sagittarii. Like M69, it sits low for northern observers. In binoculars it appears as a tiny, round fuzzy spot. A 6-inch telescope shows a bright, concentrated core. Resolving individual stars is very difficult due to the core collapse and distance. The pair of M69 and M70 can be observed in the same session. Best observed from July through September.

Discovered by Charles Messier on August 31, 1780, the same night he observed M69. On July 23, 1995, Alan Hale and Thomas Bopp independently discovered the great Comet Hale-Bopp while observing M70 — one of the most spectacular comets of the 20th century.