Messier 56 is a very old globular cluster in the Milky Way, some 31,000 light years away from Earth. It is located in the constellation of Lyra, next to Cygnus and marks the beak of the celestial swan. Lying in the plane of the Milky Way, as seen from Earth, results in the abundance of foreground stars visible in this image. It is not possible to make out M56 with the naked eye, but under a dark and clear sky, it appears as a fuzzy grey patch through large binoculars. The globular cluster was formed very early in the course of the Universe, approximately 13.7 billion years ago. This is evident due to the cluster's metallicity content. It has just 1% of the Sun’s metallicity as it is made almost entirely of hydrogen and helium. The further through time, the higher the proportion of metals can be found and astronomers can use the abundance of metals in an object to determine its age.

M56 was discovered on 23rd January 1779 by Charles Messier. It was first resolved into stars by William Herschel in 1784 using a 7-foot telescope. Containing about 230,000 solar masses, it has an average density of 2.8 solar masses per cubic light year. This makes for a very interesting image with thousands of stars visible. Because of its age, it is widely believed that M56 formed separately from the Milky Way. It is believed to have become part of our galaxy when the Milky Way devoured a smaller dwarf galaxy which contained it. The nucleus of this galaxy is thought to survive as Omega Centauri.

Messier 56 follows a retrograde orbit at around 145 km/s along a plane in the halo of the Milky Way. Astronomers have found that most clusters with this chemical makeup lie along this plane. M56’s brightest stars are of 13th magnitude and its 25 brightest stars have an average magnitude of +15. The cluster contains around a dozen variable stars including the irregular variable V2, the semi-regular variable V3 and the RV Tauri variable V6. Perhaps most spectacularly, it contains the Cepheid variable V1 which is bright enough to be followed by amateur instruments. M56 is elongated with ellipitcity 8, a concentration class X and spectral type F5. Messier 56 is a very beautiful cluster with interesting stars and a fascinating history.