Messier 21 [SEP] constellation
Messier 21
Messier 21 or M21, also designated NGC 6531, is an open cluster of stars in the constellation of Sagittarius. It was discovered and catalogued by Charles Messier on June 5, 1764. This cluster is relatively young and tightly packed. A few blue giant stars have been identified in the cluster, but Messier 21 is composed mainly of small dim stars. With a magnitude of 6.5, M21 is not visible to the naked eye; however, with the smallest binoculars it can be easily spotted on a dark
Pinwheel Galaxy
The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy distanced 21 million light-years (six megaparsecs) away from Earth in the constellation Ursa Major. Discovered by Pierre Méchain on March 27, 1781, it was communicated to Charles Messier who verified its position for inclusion in the "Messier Catalogue" as one of its final entries.
On February 28, 2006, NASA and the European Space Agency released a very detailed image of the Pinwheel