Messier 72

This is one of the most remote clusters in Messier’s catalog.

Distance

50,000 light-years

Apparent Magnitude

9.4

constellation

Aquarius

object type

Globular Cluster

As the first in the new weekly series of spectacular images from the NASA/ESA Hubble Space Telescope, the Hubble Picture of the Week, ESA/Hubble presents a stunning image of an unfamiliar star cluster. This rich collection of scattered stars, known as Messier 72, looks like a city seen from an airplane window at night, as small glints of light from suburban homes dot the outskirts of the bright city centre. Messier 72 is actually a globular cluster, an ancient spherical collection of old stars packed much closer together at its centre, like buildings in the heart of a city compared to less urban areas. As well as huge numbers of stars in the cluster itself the picture also captures the images of many much more distant galaxies seen between and around the cluster stars. French astronomer Pierre Méchain discovered this rich cluster in August of 1780, but we take Messier 72’s most common name from Méchain’s colleague Charles Messier, who recorded it as the 72nd entry in his famous catalogue of comet-like objects just two months later. This globular cluster lies in the constellation of Aquarius (the Water Bearer) about 50 000 light-years from Earth. This striking image was taken with the Wide Field Channel of the Advanced Camera for Surveys on the NASA/ESA Hubble Space Telescope. The image was created from pictures taken through yellow and near-infrared filters (F606W and F814W). The exposure times were about ten minutes per filter and the field of view is about 3.4 arcminutes across.

ESA/Hubble & NASA

Pierre Méchain, a French astronomer and colleague of Charles Messier, discovered the globular cluster M72 in 1780. It was the first of five star clusters that Méchain would discover while assisting Messier and, at a distance of 50,000 light-years from Earth, it is one of the most remote clusters in Messier’s catalog. M72 is located in the constellation Aquarius and has an apparent magnitude of 9.4. The cluster appears as a faint patch of light in small telescopes, and the best time to observe it is during September.

A globular cluster is an ancient, spherical collection of old stars that are packed very closely together toward the cluster’s center. The stars in the cluster orbit around a mutual center of gravity at this dense core. Roughly 150 globular clusters have been discovered in the Milky Way galaxy.

This image of M72 from Hubble combines observations at visible and infrared wavelengths. Capturing huge numbers of stars in the cluster itself, the picture also reveals many galaxies that are much more distant than M72, seen between and around the cluster stars.

For more information about Hubble’s observations of M72, see:

Messier 72: A Celestial City From Above

This star chart for M72 represents the view from mid-northern latitudes for the given month and time.

Image courtesy of Stellarium

Explore Hubble's Messier Catalog

The following pages contain some of Hubble’s best images of Messier objects.

Bright green, orange, and yellow tendrils intertwined within this egg shaped nebula.

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